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Pharmacogenomic research in Portugal

Irene GC Camacho

Irene Camacho, Madeira University, Faculty of Life Sciences, Campus Universitário da Penteada, 9020-105 Funchal, Portugal

E-mail : bhuvaneswari.bibleraaj@uhsm.nhs.uk

Rita PA Gonçalves

Rita Gonçalves: Human Genetics Laboratory, Madeira University, Campus Universitário da Penteada, 9020-105 Funchal, Portugal

Roberto AP Camacho

Roberto Camacho: Escola Superior de Tecnologias e Gestão, Madeira University, Campus Universitário da Penteada, 9020-105 Funchal, Portugal

DOI: 10.15761/TiM.1000259

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Abstract

Aim: To present the efforts made towards pharmacogenomic research carried out in the last two decades in Portugal.

Materials and methods: A search for Portuguese-language and English-language works reporting pharmacogenomic studies in Portugal published between 2000 and 2019 was conducted. It was performed a systematic review using the databases PubMed, Semantic Scholar and “Repositório Comum”. A list of exclusions and inclusion criteria was considered, and the selection of articles involved a two-step screening process.

Results: The search strategy included 34 studies for data extraction. Most of the published data were original articles (19) about 44% of the studies were Cohorts. Half of the studies performed only genotyping testing to characterize the population and 26,5% examined drug responses to a panel of genes and/or polymorphisms. The national surveys focused on non-communicable diseases such as Rheumatoid arthritis and Breast cancer. The genes and/or polymorphisms screened in the Portuguese population were mainly associated with drug metabolism and rheumatoid arthritis phenotypes. Of 16 diseases subjected to pharmacogenomic studies, only 5 conditions belong to the top leading causes of premature death in Portugal. On the other hand, the leading causes of disability are only partially subjected to pharmacogenomic studies.

Conclusions: The published outcomes are significant and can contribute for the improvement of personalized medicine in the country. Research should focus on the most prevailing diseases that affect the Portuguese population. The already established research consortia and networks should also make the organization and translation of pharmacogenomics studies more streamlined.

Key words

pharmacogenomics, pharmacogenes, drug therapy, personalized medicine, Portugal

Introduction

Pharmacogenomics aims to study how genetic profile influences drugs responses with the goal to improve clinical outcomes and personalizing drug therapy. As different patients don’t have the same response to the same treatment, for instance, a given drug can be beneficial for some individuals but ineffective for others or provoke adverse drug effects [1].

In the past many non-genetic factors were considered responsible for the differences in the risk-benefit ratio between patients taking the same drug. Currently, an important role in individual response to therapies is attributed to the differences in patient genetic framework. In fact, response to drug therapy is the result of the variability and synergy of all these factors. It has become clear that therapeutic and adverse effects depend on various molecular mechanisms and inter-individual genetic differences [1,2]. Such interindividual variability in therapeutic drug response can result in adverse drug reactions or lack of efficacy and represents a key challenge for health care systems. There are also evidences that genetic polymorphisms in drug metabolizing enzymes, transporters or drug targets contributing to 20–30% of these interindividual differences [3].

The treatment of common diseases often involves a series of therapeutic trials with different drugs or classes of drugs and the health-care burden imposed by inefficacy during those periods of trial and error can be considerable. The inability of a selected drug therapy to target the underlying disease mechanism, drug interactions, disease-related changes in drug concentrations or responsiveness, poor compliance, system errors, failure to deliver the correct drug or dose to the patient are common reasons for the above mentioned variability in drug response [4].

Advances in genomic science have led to the identification by regulatory agencies of a growing list of clinically important biomarkers for drug response and toxicity and created mechanisms for considering such biomarkers for targeted therapy and drug safety warnings. Clinically validated pharmacogenomic biomarkers can help physicians optimize drug selection, dose and treatment duration while averting adverse drug reactions. However, the drive to position pharmacogenomics as a core element in personalized medicine is still hindered by limited data. For example, it’s estimated that over 90% of drugs currently used in clinical practice lack valid and predictive biomarkers for therapeutic effects and/or avoiding severe side effects [5].

With the emergence of new drugs designed towards specific targets, the use of biomarkers shall increasingly allow patients to receive the drug most likely to be effective for their disease. In addition, using biomarkers to target therapies is regarded as a way towards a more efficient and cost-effective healthcare system [6].

As technology advances it is becoming clear that the broad screening of multiple pharmacogenes needs to done pre-emptively and that data should be stored in the electronic health records and drug prescription systems as well as recommendations for dosing. The pre-emptive translation of pharmacogenomic discoveries remains a challenge but implementation efforts have brought and will continue to bring more informed knowledge to constantly improve solutions [7].

In Portugal, pharmacogenomics and other “omic” information to individualize drug selection and use has some degree of weakness given it’s not routine clinical practice yet nor well known among professionals and genetic tests are rarely used for therapeutic purposes. Nevertheless, pharmacogenomics has shown a potential use in the fields of oncology and infectious diseases [8].

Considering the importance and the relevance of the subject, the present review aims to demonstrate the efforts made in pharmacogenomic until the present moment in Portugal.

Aim of the review

The present review aims at presenting the efforts made towards pharmacogenomics research carried out in the last two decades in Portugal.

Ethics approval

No approval was necessary as no patients or professionals have been the direct subject of this study.

Method

A literature search for pharmacogenetic and pharmacogenomic studies in Portugal published between 2000 and 2019 was conducted. The review followed the “Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P)”. The included databases were PubMed, Semantic Scholar and “Repositório Comum” [9] in which the following keywords where searched: pharmacogenetics, pharmacogenomics, polymorphisms, personalized medicine, Portuguese population.

A list of exclusions comprised: (1) full text unavailability, (2) conference proceedings, (3) non human studies. Duplicated studies were excluded from the final selection (Figure 1).

The selection of articles and monographies involved two screening steps: In the first step, it was screened the title, keywords with relevancy to the area of pharmacogenomics, abstract and evidence that the research was conducted in Portugal. In the second step, the full texts were checked in order to assess the last exclusion criteria.

Data extraction focused on two main topics: strategies and study characteristics. The study strategies observed were the following: (1) study type, (2) time horizon, (3) patient age range (4) pharmacogenomics approach. The study characteristics comprised the following items: (1) year of the study, (2) Portuguese region, (3) disease indication or condition, (4) drug type and category, (5) genes / polymorphisms screened and associated metabolism. Drug categorization was done according to the Anatomical Therapeutic Chemical (ATC) classification system [10].

Results

The search strategy retrieved 55 studies during the screening process (Figure 1). We excluded 3 duplicated studies, 15 non full text studies or conference proceedings and 3 non human studies. 34 studies were selected for data extraction.

Figure 1. Flow diagram of the study selection procedure

For a quick overview, data was compiled in Table 1 which shows the relevant studies in the pharmacogenomics field performed in Portugal between 2000 and 2019.

Table 1. Pharmacogenetic studies performed in Portugal (2000-2019) (references are presented by chronological order)

Population

/Region

(Type of work/approach)

 

Aims

Drug tested/ Class

Genes / SNPs / allelic variants studied or identified

Associated metabolism /disease

 

Main findings/conclusions

Ref.

80 patients

75 (control group)

 

Original article

 

Genotyping

To screen for the presence of alterations in the phenobarbital-responsive enhancer sequence of the UGT1A1 gene.

To investigate a possible association of these alterations with Gilbert syndrome (GS).

not applied

UGT1A1

c.-3279T_G

Gilbert syndrome

The c.-3279T_G polymorphism was a common finding in both GS and control individuals.

The c.-3279T_G polymorphism of the UGT1A1 gene could be an additional, if only cumulative, risk factor for the development of GS, thus justifying the inclusion of this polymorphism in routine molecular screening protocols.

[47]

 

135 healthy individuals

 

 

Original article

 

 

Only genotyping

To characterize 15 genetic polymorphisms in a population sample from Portugal.

not specified

CYP2C9 *2

CYP2C9 *3

CYP2C19

CYP3A4*1B

CYP3A5*3C

GSTP1 313A>G

GSTM1*0

ITPA 94 A>C

UGT1A1*28

UGT1A1 - 3156 G>A

ABCB1 1236 C>T

ABCB1 2677 G>A

ABCB1 2677 G>T

ABCG2 421C>A

ERCC2 2251>C

TYMS1 1494del

 

 

 

 

 

 

 

Drug metabolism

Higher frequency of CYP2D6*10, and lower frequency of CYP2D6*6, and duplication of *1 and *2 compared to European population.

The allele frequencies in the Portuguese were very similar to other Europeans. There is evidence of some African influence.

 

[8]

 

469 patients /Azores region

 

Original article

 

Only Genotyping

To assess 4 polymorphisms in 3 thrombotic risk genes in 469 healthy blood donors from Azores

To analyze the CYP2C9 (C430T, A1075C) and VKORC1 (G1639A) variants in individuals with predisposition to thrombosis to evaluate their warfarin drug response genetic profiles.

Antithrombotic Agents

F5

G1691A

Cardiovascular diseases

Azores population shows significant differences on allele frequencies of thrombotic risk factors when compared to mainland Portugal.

Thrombotic risk allele frequencies: 1691A (4.9%), 20210A (1.8%), 677T (41.7%) and 1298C (24.8%) were similar to other Caucasians, but significantly different from mainland Portuguese.

 

 

 

 

 

[30]

Warfarin

F2

G20210

 

MTHFR

C677T

A1298C

Master’s Thesis

Two distinct sub-studies were carried out: a descriptive cross-sectional study, whose information was collected from previously defined hospital services; and sub-study 2, which was based on a consensus technique - Delphi Panel.

 

 

 

 

 

Oncology

In sub-study 1 information was obtained from 4 oncologic research services, and in these services the use of genetics in therapeutic decisions, when it happens, it is not in a pharmacogenomics perspective, but from a perspective of characterizing the disease or its stage.

In sub-study 2, the institutions identified the indication of the experts, the few responses received were mostly via telephone. Data with potential in cancer prevention and chemotherapy.

 

[48]

45 patients /Centre region

 

Original article

 

Only Genotyping

To analyze the effects of multiple candidate genes on clinical improvement and occurrence of adverse drug reactions, in 45 autistic patients who received monotherapy with risperidone up to 1 year.

Candidate genes involved in the pharmacokinetics and pharmacodynamics of the drug, and the brain-derived neurotrophic factor (BDNF) gene, were analysed.

Risperidone

CYP2D6

ABCB1

HTR2A

HTR2C

DRD2

DRD3

HTR6

BDNF

 

 

 

 

 

 

Autism

Risperidone therapy is effective in reducing some autism symptoms and caused few serious adverse effects.

The HTR2A c.-1438G4A, DRD3 Ser9Gly, HTR2C c.995G4A and ABCB1 1236C4T polymorphisms were predictors for clinical improvement with risperidone therapy.

The HTR2A c.-1438G4A, HTR2C c.68G4C (p.C33S), HTR6 c.7154–2542C4T and BDNF c.196G4A (p.V66M) polymorphisms influenced prolactin elevation.

HTR2C c.68G4C and CYP2D6 polymorphisms were associated with risperidone-induced increase in BMI or waist circumference.

It was identified several genes implicated in risperidone efficacy and safety in autism patients.

 

[31]

 

92 Portuguese

151 Mozambican

91 Colombian subjects

 

Original article

 

Only Genotyping

 

To study selected genetic polymorphisms in drug metabolizing enzymes in 3 different ethnic groups - Portugal, Mozambique and Colombia.

PCR-RFLP genotyping methods were developed for drug metabolizing enzymes, namely, cholesterol 7α-hydroxylase, sterol 27-hydroxylase and oxysterol 7α-hydroxylase to characterize the allelic distribution of these polymorphisms among 3 different ethnic/geographic origins.

not specified

CYP7A1

rs3808607

rs3808608

rs3824260

rs8192874

rs58192875

rs61733615

 

 

 

 

 

 

 

Cardiovascular diseases

A total of 12 CYP7A1, CYP27A1 and CYP7B1 genetic variants were genotyped.

The variants N233S in CYP7A1 and 1774C>T in CYP7B1 were not detected in any population studied. The promoter polymorphisms in CYP7A1 (−203A>C, −346C>T, −496C>T) had high frequency in the 3 ethnic groups.

G347S (CYP7A1), R164W, A169V and V400A (CYP27A1) were present in a low frequency but with a similar distribution in the 3 groups.

Significant differences were observed for D273N (CYP27A1), −346C>T (CYP7A1), −116C>G and R324H (CYP7B1).

There is a high variability of drug metabolizing enzymes between the populations, indicating that at least some of these polymorphisms are ethnic specific.

 

[32]

 

CYP27A1

rs59443548

rs11559242

rs6994547

CYP7B1

rs5935258

rs8192907

170 asthmatic individuals and 174 healthy individuals/ Center region

 

Master’s Thesis

Only Genotyping

Determine the genotypic and allele frequencies of the repeat polymorphism in intron 4 of eNOS and of nucleotide substitution polymorphisms in amino acid 16 and 27 of ADRẞ2 in individuals suffering from asthma.

Predict a possible association between the studied genotypes and the development of the disease.

not specified

ADRẞ2

Arg16Gly

Gln27Glu

 

 

 

Asthma

It was found an association between the 27bp repeat polymorphism of the eNOS gene and susceptibility to asthma.

The prevalence of the Arg and Gly alleles of the ADRẞ2 Arg16Gly polymorphism in asthmatics is 68.3% and 31.7%, respectively.

In the ADRẞ2 Gln27Glu polymorphism, the prevalence in mutated allele (Glu) in asthma patients is higher than in the wild allele (Gln).

No association was found between eNOS or ADRβ2 polymorphisms and response to therapeutics.

[49]

eNOS

Master’s Thesis

 

Revision work about the importance of pharmacogenetics in rheumatoid arthritis.

Identified the main polymorphisms that may influence the efficacy, safety and applicability of this knowledge in clinical practice.

Immunosuppressants

 

Rheumatoid arthritis

Clinical pharmacogenetic testing is used only with AZA. The SSZ genotyping has the potential to identify patients with greater susceptibility to toxicity.

More studies are needed for the methotrexate and biological agents in order to clarify the mixed and contradictory results of the current studies.

[50]

antirheumatic agents

anti-TNF

azathioprine

methotrexate

sulfasalazine

300 healthy individuals /Center region

 

Original article

To characterize CYP2D6 polymorphisms and predict metabolic profiles in the Portuguese population.

not specified

CYP2D6*1

CYP2D6*2

CYP2D6*4

CYP2D6*10

 

 

Drug metabolism

Higher frequency of CYP2D6*10, and lower frequency of CYP2D6*6, and duplication of *1 and *2 compared to European population.


Important data in terms of effectiveness and safety in the exposure to xenobiotics, and in personalized pharmacotherapy.

[33]

Master’s Thesis

 

Revision work about the studies that demonstrate the influence of polymorphisms in the treatment of tuberculosis, aimed at the Caucasian / Portuguese population.

not applied

CYP2E1

GSTM1

GSTT1

Tuberculosis

The genotyping of certain enzymes may bring benefits not only in reducing complications and side effects, but in reducing appointments and hospitalizations.

[51]

 

101 patients

 

Madeira region

 

Doctoral Thesis

 

 

Analysis of multiple environmental factors assessed by questionnaire and the genotyping of SNPs IL131c.144 G/A, IL41590 C/T, IL41RP2 253183, ADRB21c.16 A/G, ADAM33-V4 C/G, ADAM33-S1 c.710 G/A, GSDML1236 C/T and STAT6121 C/T in a sample of Madeiran asthmatic patients and their families, and their association to asthma susceptibility and severity was assessed.

not applied

IL131-c.144 G/A

IL4-590 C/T

IL4RP2 253183

ADRB2-c.16 A/G

ADAM33-V4 C/G

ADAM33-S1 c.710 G/A

GSDML-236 C/T

STAT6-21 C/T

Asthma

IL41590*T, IL41RP2*183 as well as the combined genotypes IL41590*CT/IL41590*TT and IL41RP2*253183/IL41RP2*253183 were associated to both asthma susceptibility and severity.

GSDML1236*TT was found associated only to asthma severity.

ADAM331-V4*C was significantly over transmitted to asthmatic offspring being linked with the disease.

The findings suggest that in addition to environmental influences, IL41590 C/T, IL41RP2 253183, ADAM331V4 C/G and GSDML1236 C/T SNPs may constitute important genetic factor contributing to asthma susceptibility and/or severity in Madeira population.

 

[52]

25 patients / not specified

 

Original article

Only Genotyping

To study the association of HLA-B*58:01 with allopurinol-induced sCADR in a Portuguese population.

Antigout preparations

HLA-B*58:01

 

 

 

DRESS

SJS / TEN

 

 

HLA-B*58:01 was present in 16 patients with sCADR (64%) [12 DRESS (63%), four SJS/TEN (67%)], one allopurinol-tolerant individual (4%) and 63 normal controls.

When compared with the normal population, HLA-B*58:01 was associated with a higher risk of sCADR, both DRESS and SJS/TEN.

There was no statistically different risk between the 2 types of CADR.

Portuguese patients with sCADR from allopurinol, both DRESS and SJS/TEN, have a high frequency of HLA-B*58:01, with an OR similar to European patients with SJS/TEN.

[34]

Allopurinol

 

 

 

 

Master’s Thesis

A bibliographic review focus on pharmacogenetics and HIV therapy, looking closely at several types of antiretroviral drugs: the nucleotide reverse transcriptase inhibitors, the non-nucleotide reverse transcriptase inhibitors and the protease inhibitors and the way that several genes change the therapeutical response.

Antiretrovirals

 

HIV therapy

There is still a large amount of information that needs to be investigated and understood in relation to the possible interactions between genotypes, pharmacokinetics and pharmacodynamics of antiretrovirals.

Genetic variants are responsible for inter-individual variability, regarding the effectiveness of antiretroviral treatment and in the emergence of adverse reactions.

[62]

CCR5 antagonists

Fusion inhibitors

Integrase inhibitors

 

 

116 patients

70 Portuguese non-Gypsy (control group)

 

 / not specified

 

Master’s Thesis

 

Only Genotyping

To characterise a sample of Portuguese Gypsies for a selected panel of SNPs in genes with pharmacogenetic relevance, and to compare the derived pharmacogenetic profile with that of the Portuguese host population.

not specified

CYP2C9

rs1799853

rs1057910

 

 

 

 

Drug metabolism

For the screened variations no departures from Hardy-Weinberg equilibrium were detected in the Portuguese Gypsy and Portuguese non-Gyspy populations.

No major differences were detected in the results of the 2 populations.

[55]

CYP2C19

rs4244285

NAT2

rs1041983

rs1801280

TPMT

rs1800462

rs1800460

rs1142345

rs56161402

VKORC1

rs9923231

51 patients / Centre

 

 

Master’s Thesis

 

Only Genotyping

To characterize a sample of Portuguese diabetic individuals, through survey of a single nucleotide polymorphisms set identified in the literature and databases (related to pharmacogenetics of DM2 in coding region and for the European population (EUR)), followed by a correlation of the results with the drugs administered to individuals in the sample.

To propose a set of SNPs candidates for pharmacogenetics of DM2.

 

Sulphonylureas Glibenclamida

Gliclazida

Glimepirida

Sulphonylureas

Tolbutamida

 Tolbutamida

ABCC8

rs1799859

rs1801261

 

 

 

 

 

Diabetes Mellitus type 2 (DM2)

There were identified SNPs associated with pharmacogenetics of DM2 in scientific articles and databases, where a total of 98 SNPs were identified.

The SNPs were filtered for those in the coding region and associated with the EUR population.

Sixteen SNPs were observed in 10 genes in the 51 patients.

Correlation of drugs administered in the sample in study with the results from the survey of these SNPs, indicated that individuals carrying the SNPs rs12208357, rs34130495 and rs3405950 (SLC22A1) needed a higher dose of metformin, the carriers of SNP rs1801282 (PPAR) needed tighter control treatment metformin (given the increased risk of failure for this treatment) and carriers of SNP rs5219 (KCNJ11) needed a higher dose of gliclazide.

It was proposed a set of potential SNPs candidates for future studies concerning the pharmacogenetics of DM2 in the Portuguese population 32 SNPs located in the coding region and not yet referenced in the EUR population were selected from the set of 98 SNPs.

Additional 15 SNPs not yet related to the DM2 were also identified in the 51 patients.

[53]

CYP2C9

 

rs1799853

rs1057910

IRS1

rs1801278

KCNJ11

rs5219

Meglitinides

 

Repaglinida

Nateglinida

 

CYP2C8

rs10509681

rs11572080

CYP2C9

rs1057910

SLCO1B1

rs4149056

rs2306283

Thiazolidinediones

 

Rosiglitazona

Pioglitazona

CYP2C8

rs10509681

rs11572080

Biguanides

 

Metformina

 

SLC22A1

rs72552763

rs35167514

rs12208357

rs34130495

rs34059508

rs1867351

PPARγ

rs1801282

Inibitors of α glicosidase

 

Acarbose

PGC-1α (PPARGC1A)

rs8192678

 

GLP-1 and analogues

 

GLP-1

THADA

rs7578597

Master’s Thesis

 

A review work that aimed at present an overview on the state of the art of pharmacogenomics, with the introduction of its basic concepts, how genetic polymorphisms may modulate individual’s susceptibility to certain diseases or influences the therapeutic efficacy and safety of drugs.

not applied

 

 

It was concluded that Pharmacogenomics has reached a state in which it makes possible, if not an individual tuning of the pharmaceutical regímen, at leats the definition of groupings of individuals with similar genetic profiles and a corresponding more homogeneous response to drugs.

[54]

242 patients

 

/Center

 

Original article

Only Genotyping

To identify clinical and/or genetic predictors of response to several therapies in Crohn’s disease (CD) patients.

Immunosuppressants

ABCB1 C3435T, G2677T/A IL23R G1142A

C2370A

G9T

CASP9 C93T

Fas G670A

LgC844T

ATG16L1 A898G

 

 

 

 

 

 

Crohn’s disease

Older patients responded better to 5-aminosalicylic acid (5-ASA) and to azathioprine while younger ones responded better to biologicals.

Previous surgery negatively influenced response to 5-ASA compounds but favoured response to azathioprine.

Heterozygotes for ATGL16L1 SNP had a significantly higher chance of responding to corticosteroids, while homozygotes for Casp9 C93T SNP had a lower chance of responding both to corticosteroids and to azathioprine.

TT carriers of ABCB1 C3435T SNP had a higher chance of responding to azathioprine, while carriers of ABCB1 G2677T/A SNP, as well as responding better to azathioprine, had a lower chance of responding to biologicals, which became significant after adjusting for gender.

[35]

 

Azathioprine

Biologicals

 

Corticosteroids

 

 

 

 

 

 

 

Cohort

 

Original article

To elucidate the role of methylenetetrahydrofolate reductase (MTHFR) C677T and aminoimidazole carboxamide adenosine ribonucleotide transformylase (ATIC) T675C polymorphisms and clinicopathological variables in clinical response to MTX in Portuguese rheumatoid arthritis (RA) patients.

Methotrexate

MTHFR C677T

ATIC T675C

Rheumatoid Arthritis

MTHFR 677TT and ATIC 675T carriers were associated with over 4-fold increased risk for nonresponse.

For clinicopathological variables, noncurrent smokers, patients positive to anti-cyclic citrullinated peptide and antinuclear antibodies, with higher health assessment questionnaire score, and nonsteroidal anti-inflammatory drug users were also associated with nonresponse.

Subcutaneous administration route was associated with response.

MTHFR C677T and ATIC T675C genotyping combined with clinicopathological data may help to identify patients who will not benefit from MTX treatment and, therefore, assist clinicians in personalizing RA treatment.

[36]

233 Caucasian /

North region

Original article

To elucidate the influence of TYMS polymorphisms in MTX therapeutic outcome (regarding clinical response and toxicity) in Portuguese RA patients.

Methotrexate

TYMS

rs34743033

rs2853542

rs34489327

Rheumatoid Arthritis

TYMS polymorphisms could be important to help predicting clinical response to MTX in RA patients.

Translation into clinical practice needs larger studies to confirm the evidences.

[37]

233 patients

North region

Original article

 

To evaluate the influence of single nucleotide polymorphisms (SNPs) in genes encoding for MTX transporters with the occurrence of MTX-related toxicity (overall and gastrointestinal).

Methotrexate

SLC16A7

rs3763980

rs10877333

Rheumatoid Arthritis

SLC19A1, SLC46A1 and SLCO1B1 genotypes may help to identify patients with increased risk of MTX-related overall toxicity and that SLC19A1 and SLCO1B1 genotypes, and SLC19A1 haplotypes may help to identify patients with increased risk of MTX-related gastrointestinal toxicity.

[38]

SLC19A1

rs7499

rs1051266

rs2838956

rs3788200

SLC22A6

rs11568626

SLC22A11

rs11231809

SLC46A1

rs2239907

SLCO1B1

rs4149056

ABCB1

rs1045642

rs1128503

rs2032582

ABCC1

rs35592

rs246240

rs2074087

rs2230671

rs3784864

ABCC2

rs717620

rs4148396

ABCG2

rs2231142

rs13120400

rs17731538

Master’s Thesis

 

 

 

A review work about Pharmacogenomics of addiction

not applied

SNP

VNTR

Drug addiction

Drug addiction remains an unsolved health issue and has limited treatment options currently available.

The existing medications were not developed having a thorough knowledge of genetic and neurobiological causes of the disease.

More replication data is needed concerning some genetic variants to allow the identification of functional variants, but also the need for larger population samples has become clear for detecting small effect variants from the many genes accountable for addiction.

[56]

Master’s Thesis

A bibliographic review on pharmacogenetics in the treatment of breast cancer.

To study of the influence that genetic polymorphisms of metabolic enzymes, efflux transporters and estrogen receptors, have on response to tamoxifen therapy for breast cancer

not applied

CYP2C19*2

CYP2C19*17

CYP3A4

CYP3A4*22

CYP3A4*1B

CYP3A5

SULT1A1

SULT1A1*2

Breast cancer

Studies that analysed the role of CYP2D6 genotype in response to tamoxifen are controversial, most of these argue that poor metabolizers and intermediate have worse results than extensive metabolizers, although in only one of the studies with higher impact the same association was observed.

In the CYP3A4, the T allele for the CYP3A4*22 polymorphism was associated with higher concentration of tamoxifen and its metabolites and CYP3A4*1B polymorphism was associated with increased risk of developing endometrial cancer.

The polymorphisms at the estrogen receptors have demonstrated an important role in modulating the response to tamoxifen treatment on regards secondary and adverse effects. Larger population and greater control over variables are needed to reach a personalized medicine.

[57]

Lisbon

Porto

Coimbra

Master’s Thesis

Evaluation of pharmacogenomics in Portuguese clinical practice, identification of the skills and techniques for the application of pharmacogenomics and the potential areas of pharmacogenomics in clinical practice.

Azathioprine

not specified

Oncology and

infectious diseases

 

Pharmacogenomics/genetics in Portugal has some degree of weakness; is not a routine in clinical practice, not well known among professionals, genetics is not mainly use for therapeutic purposes.

The service of IPO Lisbon uses de detection of Human Epidermal growth factor Receptor-type 1 (HER1) for specific therapeutics of breast cancer.

[58]

Original article

 

To revise the major definitions in the pharmacogenetics as well as some classic examples of its application (related to cytochrome P450 genes, NAT2 gene and the Cholinesterase gene; the multitude of existing drug targets, like in case of G6PD gene, and the VKORC1 gene).

not applied

P450 genes

NAT2

G6PD VKORC1

not applied

Pharmacogenetics contribute to the development of new drugs, since it gives an important data, namely the knowledge of the potential variability associated with metabolization and/or action of the drug.

In addition, pharmacogenetics also plays an important role in reducing the number of patients who must participate in clinical trials, and potentially reduce the risk of failure in the lead-up stages in the market.

[39]

52 individuals with a suggestive phenotype of

trimethylaminuria and 100 healthy individuals/ not specified

 

Original article

Only Genotyping

Portuguese patients with phenotype suggestive of TMAu were evaluated for molecular screening of the FMO3 gene.

not specified

 

FMO3

 

 

 

TMAu

Identification of 32 variants in the FMO3 coding region.

P.Glu158Lys and p.Glu308Gly polymorphisms, in combination with other variants, originate different phenotypic patterns, which may lead to an abnormal drug metabolism in the liver and other organs and tissues.

[40]

 

 

208 patients / South region

 

Original article

 

Genotyping and drug testing

 

 

 

 

 

To assess the pharmacogenetic profile of a South Portuguese population according

to established dosing guidelines for commonly prescribed drugs and to compare it with that of previously genotyped populations.

Thiopurines

Clopidogrel

Warfarin

Fluoropyrimidines

Irinotecan

Codeine

Tricyclics

ABCB1

rs1045642

rs1128503

rs2032582

Drug metabolism

 

It was found a significant small differentiation between the Portuguese regional populations regarding CYP2C9 rs1057910, CYP2D6 rs3892097, MTHFR rs1801133 and F5 rs6025.

When considering 4 HapMap populations, ADH1B rs2066702, ADH1B rs1229984, NAT2 rs1799931 and VKORC1 rs9923231 displayed a significant population differentiation.

18.9% of the participants are intermediate or poor metabolizers for at least 3 drugs simultaneously and that 84.6% of the participants have at least one therapeutic failure or ADR risk allele for the considered drugs.

There is a high prevalence of risk alleles associated with an altered drug metabolism regarding drugs largely used by the South Portuguese population.

[41]

 

ADH1B

rs1229984

ADH1C

rs698

ADRB2

rs1042714

COMT

rs4680

CYP2C19

rs4244285

rs4986893

CYP2C8

rs11572080

CYP3A5

rs776746

CYP2D6

rs3892097

DPYD

rs67376798

rs1801265

rs55886062

F5

rs6025

GSTP1

rs1695

KCNJ11

rs5219

TPMT

rs1800462

rs1800460

rs1800584

rs1142345

233 patients /North

 

Original article

 

Genotyping and drug testing

 

 

Clinicopathological data from rheumatoid arthritis patients treated with methotrexate were collected, clinical response defined, and patients genotyped for 23 single nucleotide polymorphisms.

Genotype and haplotype analyses were performed using multivariate methods and a genetic risk index for non-response was created

Immunosuppressants

Antimetabolites

SLC16A7

rs3763980

rs10877333

 

 

 

Rheumatoid Arthritis

Genetic polymorphisms in SLC22A11 and ABCC1 could be predictors of clinical response to methotrexate in Portuguese rheumatoid arthritis patients.

Genotyping patients according to these genetic markers may be helpful to identify which patients will not benefit from methotrexate treatment, highlighting the relevance of developing the field of personalized medicine.

[42]

Methotrexate; Methotrexate + drug panel

SLC19A1

 

rs7499

rs1051266

rs2838956

rs3788200

SLC22A11

rs11231809

SLC46A1

rs2239907

SLCO1B1

rs4149056

167 patients

Original article

 

Genotyping and drug testing

 

To evaluate the repercussion of personalization of INH dosing by NAT2 genotyping in the management of tuberculosis patients.

To assess the role of other candidate genes like CYP2E1, GSTM1 and GSTT1 encoding detoxifying enzymes, and ABCB11, encoding a protein involved in bile salt transport.

 

 

Antimycobacterials

NAT2 

CYP2E1

GSTM1

GSTT1

ABCB11

 

 

 

 

 

Tuberculosis

Clinical variables such as gender and age were not associated with the occurrence of INH-induced hepatitis.

Slow acetylators (52.3%), identified by NAT2 genotyping, were significantly more prone to develop, as well as homozygous for variant Ala of ABCB11 polymorphism (rs2287622).

The presence of both risk genotypes was also significantly associated with increased susceptibility to hepatotoxicity.

Risk genotypes were frequent among patients: 52% of SA (NAT2), 32% of Ala/Ala (ABCB11) and 21% with both risk genotypes.

[43]

 

Isoniazid

 

 

 

 

 

 

Master’s Thesis

To develop a Sanger sequencing methodology for CYP2D6 gene to identify genetic variants that cause absence of enzyme activity and its application to post-mortem cases with tramadol

Tramadol

CYP2D6

 

 

The methods were successfully applied to post mortem blood samples.

Alleles and genotype frequencies were in accordance with the expected for European population.

Tramadol metabolism, expressed as its metabolites concentration ratio (N-desmethyltramadol/O-desmethyltramadol), has been shown to be correlated with the predicted phenotypes based on genetic characterization.

This is presumably the first time that a CYP2D6 sequencing methodology is validated and applied to post-mortem samples, in Portugal.

[59]

56 Portuguese gypsies / not specified

 

Master’s Thesis

 

Only Genotyping

To characterize the Portuguese Roma for Single Nucleotide Polymorphisms (SNPs), relevant from the Pharmacogenetics point of view.

 

To evaluate if the Roma show any peculiarity regarding drug response, in comparison with the host population.

not specified

CYP2D6

rs1065852

rs28371706

rs61736512

rs3892097

s35742686

rs5030656

rs16947

rs28371725

rs59421388

rs1135840

 

 

 

 

Drug metabolism

 

 

For the variations studied, only one SNP revealed significant deviation from the Hardy – Weinberg expectation, even after the Bonferroni correction, which was the 4180 G>C.

Comparatively to the Portuguese host population, the Roma showed some differences, especially an increased frequency of the CYP2D6*4, an allele implying null enzymatic activity.

Regarding the theoretical metabolic profiles, differences were found, especially the IM and PM profiles.

[60]

1688 patients / North, Centre, South regions

 

Original article

 

Genotyping and drug testing

 

To determine the prevalence of genotypes associated with a lower efficacy or a higher risk of adverse side effects in the treatment with statins in the Portuguese population.

Several SNPs involved in the metabolism, absorption, transport and/or excretion of the various types of statins were genotyped.

Statins

 

SLCO1B1

rs4149056

 

 

 

 

Dyslipidaemia

The SLCO1B1*5 variant, associated with an increased risk of developing myopathy on simvastatin treatment, has a frequency 2 times higher in the sample than described in the population databases. This fact, coupled with the large increase in national consumption of statins, mainly simvastatin, is an important factor that should be considered in the decision-making of the prescription of antidislipidemics.

 

 

[44]

APOE

rs7412

ABCB1

rs2032582

KIF6

rs20455

HMGCR

rs17238540

POR

rs1057868

ABCB1

rs1045642

CYP3A5

rs776746

CYP2C9

rs1057910

Master’s Thesis

To relate the knowledge underlying the field of Pharmacogenetics with pharmaceutical activity in the hospital context, reviewing the most important topics in this area for hospital pharmaceutical practice.

not specified

 

Oncology

The pharmacist assumes a central role in the implementation of Pharmacogenetics in clinical practice, since is a health professional with basic knowledge important for understanding this area, having the duty to specialize and help to instruct the remaining members of the research team health about the correct interpretation of the results of pharmacogenetic tests and the best way to apply them.

[61]

Original article

To investigate the impact of CYP2D6 genotyping of the tamoxifen metabolizing enzymes in the clinical management of breast cancer patients.

Tamoxifen

CYP2D6

Breast cancer

Portugal presents an interesting case for comparison in international pharmacogenomics context. This is especially the case of CYP2D6 testing prior to tamoxifen therapeutics. This is because there are no implemented measures based on pharmacogenomics analysis prior to therapy. Changing clinical paradigms involves assessment of several factors and a country with a clinical context as that of Portugal might function as a sample control in such analysis.

[46]

Original article

 

Genotyping and drug testing

 

To report on the real-life experience of 2 Portuguese dermatology departments with ustekinumab in patients with moderate to severe psoriasis.

To identify the clinical characteristics associated with a weaker clinical response.

Immunosuppressants

HLACw*0602

 

 

 

 

Psoriasis

A PASI75 therapeutic response was observed in 67.2%, 85.3%, 89.6% and 88.7% of patients at weeks 4, 12, 24 and 52, respectively.

Neither cardiovascular events nor cases of reactivation of previous infections (tuberculosis, hepatitis B) were observed during follow-up.

The therapeutic response was higher in patients naïve to biologic therapies as compared to non-naïve patients.

A trend towards lower clinical response was observed in patients weighing between 90-100 kg, and dosage optimization in these patients may be of value prior to considering biologic switch.

[45]

Ustekinumab

 

 

 

 

Summary of the study strategies

Most of the published data were original articles (19) and the remainder were monographies (15). About 44% of the studies were Cohorts and a minority randomized controlled trials (15%) (Table 2). The majority did not specify a time horizon (79,4%) nor had indication of the patients age range (70,6%). Half of the studies performed only genotyping testing to characterize the population and 9 (26,5%) examined drug responses to a panel of genes and/or polymorphisms (Tables 1 and 3).

Table 2. Summary of study strategies (N=34)

Type of study

n

%

Cohort

15

44

Review

8

24

Genotype-based screening

6

18

Randomized controlled trial

5

15

Time horizon

 

 

Lifetime

0

0,0

≥20 years

0

0,0

3-10 years

4

11,8

≤3 years

3

8,8

No statement

27

79,4

Patient age range

 

 

≥ years

1

2,9

< 60 years

9

26,5

Not stated or not applicable

24

70,6

Pharmacogenomics approach

 

 

Study focused only on genetic/genomic testing

17

50,0

Genotyping and drug testing

9

26,5

None of the above

8

23,5

Table 3. Summary of study strategies (N=34)

Drug

Category

n

%

Methotrexate; Methotrexate + drug panel

Immunosuppressants; Antimetabolites

7

20,6

Clopidogrel, Warfarin

Antithrombotic agents

2

5,9

 Azathioprine, Biologicals, Corticosteroids

Corticosteroids, Immunosuppressants; biologics

1

2,9

Allopurinol

Antigout preparations

1

2,9

Azathioprine, Sulfasalazine, Methotrexate, Biological agents

Immunosuppressants; Intestinal anti-inflammatory agents; Antimetabolites; Biologics

1

2,9

Biguanides, Meglitinides, Sulphonylureas, Thiazolidinediones

Blood glucose lowering drugs

1

2,9

Codeine

Anti-infectives

1

2,9

Fusion inhibitors, CCR5 antagonists, Integrase inhibitors

Antiretrovirals

1

2,9

Isoniazid

Antimycobacterials

1

2,9

Risperidone

Psycholeptics, Antipsychotics

1

2,9

Statins

Lipid modifying agents

1

2,9

Tamoxifen, Irinotecan

 Antineoplastic and Immunomodulating agents

1

2,9

Tramadol

Analgesics

1

2,9

 Ustekinumab

Immunosuppressants

1

2,9

 not specified

13

38,2

Summary of the study characteristics

Studies published between 2011 and 2014 were 61,8% of the total whereas 26,5% were published prior to 2010. Most of the research omitted the place of origin of the patients (70,6%) whilst the populations from North and Centre of Portugal were the most represented in the studies (20,6%) (Table 4).

Table 4. Summary of study characteristics (N=34)

Year

n

%

2007-2010

4

11,8

2011-2014

21

61,8

2015-2018

9

26,5

Portuguese region

 

 

North

3

8,8

Centre

4

11,8

South

1

2,9

Azores

1

2,9

Madeira

1

2,9

Not specified or not applicable

24

70,6

Disease indication or condition

 

Rheumatoid Arthritis

5

14,7

Breast Cancer

3

8,8

Asthma

2

5,9

Tuberculosis

2

5,9

Cardiovascular diseases

2

5,9

Autism

1

2,9

Crohn’s disease

1

2,9

Diabetes mellitus type 2

1

2,9

Drug addiction

1

2,9

DRESS; Stevens–Johnson Syndrome (S-JS) / Toxic Epidermal Necrolysis (TEN)

1

2,9

HIV

1

2,9

Leukemia

1

2,9

Lung cancer and Metastatic colorectal cancer

1

2,9

Psoriasis

1

2,9

Severe dyslipidemia

1

2,9

Trimethylaminuria

1

2,9

not specified

9

26,5

The illness kind that deserved more attention from the local scientific community was heterogeneous (Table 4), namely the non-communicable diseases such as Rheumatoid arthritis and Breast cancer.

Similarly, the set of genes and/or polymorphisms screened or tested in the Portuguese population were mainly associated with drug metabolism and rheumatoid arthritis phenotypes (11.8%) (Table 1). About 35,3% of the studies presented a diverse set of analysed genes. The studied drug types were very diverse (Tables 1, 3, 4), being the immunosuppressants and antimetabolites the most tested categories (20,6%).

Research trends on pharmacogenomics in portugal

An overview of the research trends in pharmacogenomics and the leading causes of disability and premature death in the country is illustrated in Figure 2. From 16 diseases or conditions subjected to pharmacogenomic studies, only 5 (Breast cancer, Cardiovascular diseases, Diabetes, Lung cancer and Metastatic colorectal cancer) belong to the list of top leading causes of premature death in Portugal. In addition, the leading causes of disability (Cardiovascular diseases, Diabetes, Lung cancer and Metastatic colorectal cancer) are only partially subjected to pharmacogenomic studies. Most of the disabling diseases reported in the country are non-communicable diseases, namely those related with low back and neck pain and the cardiovascular system [11,12].

Figure 2. Correspondence between investigated diseases (present review) and the leading causes of disability and premature death in portugal (DGS, 2018)

Discussion

Pharmacogenomic research represents an important tool in drug development and pharmacovigilance, which helps the improvement of healthcare [13]. Several options are available for the design of pharmacogenomic studies, among them the case-control study, cohort and randomised controlled clinical trials (RCTs) [14]. The study types performed in the pharmacogenomic area in Portugal were mostly cohorts (44%). In such cases, participants are enrolled based on their phenotype or drug response and information regarding their exposures are collected retro- or prospectively. This covers any number of exposures (medical, environmental, comorbidities, etc.) as well as a DNA sample for genotyping [15,16].

As the research progresses we should expect an increase of cohort and of RCTs studies in order to assess potential drug-gene interactions [14]. RCTs are considered the gold standard of study designs in pharmacogenomic-guided treatment approach. The lack of such research impairs the clinical utility and validity of pharmacogenomic testing [17].

Our findings showed that 50% of the studies in Portugal performed only genotyping testing to characterize the population, whereas 26.5% did drug testing for a disease or condition besides genotyping. The reported sample sizes are small, in line with many pharmacogenomics trials or drug response studies which had very limited sample sizes [16].

Globally, laboratories which perform pharmacogenomic tests are still few, reflecting low clinical uptake, and our country is not an exception.Known reasons for the so far rather limited clinical implementation of pharmacogenomic testing include the following common barriers: scientific, educational, legal, ethical, social issue (ELSI), lack of information technology, reimbursement besides other barriers have been identified worldwide [17,18]. Regulations regarding Direct to Consumer (DTC) genetic testing including pharmacogenomic testing differ in scope and strictness from country to country. Laws in Portugal, France, Germany and Switzerland restrict the prescription of genetic tests by physicians after counselling and proper informed consenting process, which makes DTC genetic tests illegal in these countries [19].

Apart from the legal issues, each clinical practice setting has its own requirements for implementation and few physicians and health systems use pharmacogenomic in clinical practice [17]. As in other European countries, the majority of the pharmacogenomic surveys that took place in Portugal were developed in collaboration with medical institutions, Universities and research laboratories, a strategy that favors the integration of pharmacogenomics in the healthcare system.

We have found that over half (61.8%) of the studies were published between 2011 and 2014. In fact, pharmacogenomic testing worldwide has been performed since the last decade [20]. Also, the number of published economic evaluation analyses in the field of genomic and personalized medicine was particularly evident since 2011 [21]. As such, it is expected that more cost-effective analyses should cover as many populations and/or ethnic groups as possible in various countries [21], including Portugal.

It was shown that the diseases or conditions that gain most of the attention of the Portuguese scientific community, from a pharmacogenomic perspective, were Rheumatoid Arthritis, Breast cancer, Asthma, Cardiovascular diseases, and the communicable disease Tuberculosis. On the other hand, our survey revealed that the leading causes of disability in Portugal were only partially subjected to pharmacogenomic studies, namely those related with Cardiovascular diseases (stroke and ischemic heart disease), Lung cancer and Metastatic colorectal cancer. Most of the listed diseases (Figure 2) are complex disorders which, according to Warnich et al. [22], demand high standard genomics studies so that they can be integrated into a holistic approach adapted to the individual profile and preferences.

Regarding the Portuguese situation, there are strict laws on genetic testing. Firstly, a national law imposes that diagnostic or pharmacogenetic testing should follow the general principles of all other health care interventions. Secondly, when a hereditary disease is identified in a patient, the physician should inform the patient about the mechanism of transmission and refer him/her to a genetics team. Nevertheless, the advances in the implementation of personalized medicine at a national level, as in most of the countries currently involved in pharmacogenomic research, have been made essentially in the area of oncology and rare diseases [23,24]. On regards to rare diseases, genomic tests and pre-emptive genotyping have been directed to those specific populations which cannot be easily treated with conventional interventions or based on drugs with narrow therapeutic windows. Pre-emptive genotyping is often crucial for a specific population, in particular in carriers of the HLA-B*1502 allele which have a high risk of developing Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN). Studies in different populations, including in Portugal, reported a prevalence of the HLA-B*5701 gene of 3.7-6.1%, which justifies the importance to pursuit with the pharmacogenomic research in the Portuguese population.

It’s expected that the introduction of genomic testing in clinical practice will contribute to the rationalization of established drug-prescription regimens and lead to the design of new individualized interventions with maximized efficacy and minimized adverse drug reactions [21]. Currently, all countries are at different stages of clinical implementation or undergoing implementation projects to improve their strategy. In addition, the development of pharmacogenomics has not been as fast as expect and the Portuguese reality is similar that of other countries. According to Warnich et al. [22], to ensure sustainable research in pharmacogenomics in a country, particular attention should be given to key areas with regards to genomic study design: (i) national and international multi-disciplinary collaborations, consortia and research networks, (ii) the collection and storage of biological samples in biorepositories. On this respect, several ongoing initiatives of pharmacogenomic implementation have been launched in Europe, United States and Asia [7,25]. Two Portuguese entities (Ricardo Jorge Institute and Foundation for Science and Technology) along with more than 35 European and international institutions, are part of the ICPerMed Consortium that aims to identify and implement priority actions in personalised medicine research [26]. Ultimately, the set up of such consortia and research networks benefits the organization and extension of pharmacogenomic studies.

This review has shown that Portugal has capabilities to increase research in the field of genomic medicine, using its know-how on genotyping and genome sequencing for disease prediction, diagnosis, prevention and treatment. The CYP2D6 gene and others CYP genes and its polymorphisms have been the most screened in the Portuguese population. This evidence is not surprising, considering that CYP2D6 is one of the most extensively studied drug-metabolizing enzymes and pharmacogenes [27]. Further, the CYP genes are ubiquitous in nature, when expressed they function on many substrates and show an overlap of substrate specificities [28].

As in other similar countries, the national pharmacogenomic research has focused on a few common gene variants, although with large size effects. This spectrum of effects has complicated the design and lead to large clinical trials that often focus on individual drugs [4,22], a fact also reported in our work. It’s known that variation in drug response may be due to multiple genes, each with small effects. In these cases, large sample sizes will be needed to identify the effects [16].

Lastly, the most studied drug types nationwide from a pharmacogenomic perspective were the ones associated with the treatment of the respective illness or condition (Table 4). However, pharmacogenomic studies should focus on drugs used in the treatment of the diseases that contribute to the highest disease burden faced by the population [22].

Important steps to determine the prevalence of the pharmacogenomic biomarkers in our population were taken. On this respect, Mizziet al. [29], stressed that the frequency of a high-risk pharmacogenomic biomarker alone is not adequate for developing national medication guidelines, but rather in conjunction with other factors, such as the previously mentioned disease burden.

Conclusions

Most research on pharmacogenomics performed in Portugal occurred in the early 2010’s and half of the studies performed only genotyping testing to characterize the population. The core investigation focused on non-communicable diseases like Rheumatoid arthritis, Breast cancer and Asthma.

As in other countries, regular pharmacogenomic testing is still scarce in the country and the leading causes of disability are only partially subjected to pharmacogenomic studies. However, there is a growing interest in research in pharmacogenomic area. The published results are significant and can contribute for the improvement of personalized medicine. The already established research consortia and networks should also make the organization and translation of pharmacogenomics studies more streamlined.

Acknowledgements

The authors are grateful to Physician Dr. Cristiana Granito Camacho from the Hospital de São Francisco Xavier (Lisbon) for the proofreading and valuable comments.

Funding

None.

Conflicts of interest

None.

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Editorial Information

Editor-in-Chief

Ying-Fu Chen
Kaohsiung Medical University, Taiwan

Article Type

Research Article

Publication history

Received date: September 09, 2020
Accepted date: October 02, 2020
Published date: October 07, 2020

Copyright

©2020 Camacho IGC. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Citation

Camacho IGC, Gonçalves RPA, Camacho RAP (2020) Pharmacogenomic research in Portugal. Trends Med 20: DOI: 10.15761/TiM.1000259

Corresponding author

Irene Camacho

Madeira University, Faculty of Life Sciences, Campus Universitário da Penteada, 9020-105 Funchal, Portugal

E-mail : bhuvaneswari.bibleraaj@uhsm.nhs.uk

Figure 1. Flow diagram of the study selection procedure

Figure 2. Correspondence between investigated diseases (present review) and the leading causes of disability and premature death in portugal (DGS, 2018)

Table 1. Pharmacogenetic studies performed in Portugal (2000-2019) (references are presented by chronological order)

Population

/Region

(Type of work/approach)

 

Aims

Drug tested/ Class

Genes / SNPs / allelic variants studied or identified

Associated metabolism /disease

 

Main findings/conclusions

Ref.

80 patients

75 (control group)

 

Original article

 

Genotyping

To screen for the presence of alterations in the phenobarbital-responsive enhancer sequence of the UGT1A1 gene.

To investigate a possible association of these alterations with Gilbert syndrome (GS).

not applied

UGT1A1

c.-3279T_G

Gilbert syndrome

The c.-3279T_G polymorphism was a common finding in both GS and control individuals.

The c.-3279T_G polymorphism of the UGT1A1 gene could be an additional, if only cumulative, risk factor for the development of GS, thus justifying the inclusion of this polymorphism in routine molecular screening protocols.

[47]

 

135 healthy individuals

 

 

Original article

 

 

Only genotyping

To characterize 15 genetic polymorphisms in a population sample from Portugal.

not specified

CYP2C9 *2

CYP2C9 *3

CYP2C19

CYP3A4*1B

CYP3A5*3C

GSTP1 313A>G

GSTM1*0

ITPA 94 A>C

UGT1A1*28

UGT1A1 - 3156 G>A

ABCB1 1236 C>T

ABCB1 2677 G>A

ABCB1 2677 G>T

ABCG2 421C>A

ERCC2 2251>C

TYMS1 1494del

 

 

 

 

 

 

 

Drug metabolism

Higher frequency of CYP2D6*10, and lower frequency of CYP2D6*6, and duplication of *1 and *2 compared to European population.

The allele frequencies in the Portuguese were very similar to other Europeans. There is evidence of some African influence.

 

[8]

 

469 patients /Azores region

 

Original article

 

Only Genotyping

To assess 4 polymorphisms in 3 thrombotic risk genes in 469 healthy blood donors from Azores

To analyze the CYP2C9 (C430T, A1075C) and VKORC1 (G1639A) variants in individuals with predisposition to thrombosis to evaluate their warfarin drug response genetic profiles.

Antithrombotic Agents

F5

G1691A

Cardiovascular diseases

Azores population shows significant differences on allele frequencies of thrombotic risk factors when compared to mainland Portugal.

Thrombotic risk allele frequencies: 1691A (4.9%), 20210A (1.8%), 677T (41.7%) and 1298C (24.8%) were similar to other Caucasians, but significantly different from mainland Portuguese.

 

 

 

 

 

[30]

Warfarin

F2

G20210

 

MTHFR

C677T

A1298C

Master’s Thesis

Two distinct sub-studies were carried out: a descriptive cross-sectional study, whose information was collected from previously defined hospital services; and sub-study 2, which was based on a consensus technique - Delphi Panel.

 

 

 

 

 

Oncology

In sub-study 1 information was obtained from 4 oncologic research services, and in these services the use of genetics in therapeutic decisions, when it happens, it is not in a pharmacogenomics perspective, but from a perspective of characterizing the disease or its stage.

In sub-study 2, the institutions identified the indication of the experts, the few responses received were mostly via telephone. Data with potential in cancer prevention and chemotherapy.

 

[48]

45 patients /Centre region

 

Original article

 

Only Genotyping

To analyze the effects of multiple candidate genes on clinical improvement and occurrence of adverse drug reactions, in 45 autistic patients who received monotherapy with risperidone up to 1 year.

Candidate genes involved in the pharmacokinetics and pharmacodynamics of the drug, and the brain-derived neurotrophic factor (BDNF) gene, were analysed.

Risperidone

CYP2D6

ABCB1

HTR2A

HTR2C

DRD2

DRD3

HTR6

BDNF

 

 

 

 

 

 

Autism

Risperidone therapy is effective in reducing some autism symptoms and caused few serious adverse effects.

The HTR2A c.-1438G4A, DRD3 Ser9Gly, HTR2C c.995G4A and ABCB1 1236C4T polymorphisms were predictors for clinical improvement with risperidone therapy.

The HTR2A c.-1438G4A, HTR2C c.68G4C (p.C33S), HTR6 c.7154–2542C4T and BDNF c.196G4A (p.V66M) polymorphisms influenced prolactin elevation.

HTR2C c.68G4C and CYP2D6 polymorphisms were associated with risperidone-induced increase in BMI or waist circumference.

It was identified several genes implicated in risperidone efficacy and safety in autism patients.

 

[31]

 

92 Portuguese

151 Mozambican

91 Colombian subjects

 

Original article

 

Only Genotyping

 

To study selected genetic polymorphisms in drug metabolizing enzymes in 3 different ethnic groups - Portugal, Mozambique and Colombia.

PCR-RFLP genotyping methods were developed for drug metabolizing enzymes, namely, cholesterol 7α-hydroxylase, sterol 27-hydroxylase and oxysterol 7α-hydroxylase to characterize the allelic distribution of these polymorphisms among 3 different ethnic/geographic origins.

not specified

CYP7A1

rs3808607

rs3808608

rs3824260

rs8192874

rs58192875

rs61733615

 

 

 

 

 

 

 

Cardiovascular diseases

A total of 12 CYP7A1, CYP27A1 and CYP7B1 genetic variants were genotyped.

The variants N233S in CYP7A1 and 1774C>T in CYP7B1 were not detected in any population studied. The promoter polymorphisms in CYP7A1 (−203A>C, −346C>T, −496C>T) had high frequency in the 3 ethnic groups.

G347S (CYP7A1), R164W, A169V and V400A (CYP27A1) were present in a low frequency but with a similar distribution in the 3 groups.

Significant differences were observed for D273N (CYP27A1), −346C>T (CYP7A1), −116C>G and R324H (CYP7B1).

There is a high variability of drug metabolizing enzymes between the populations, indicating that at least some of these polymorphisms are ethnic specific.

 

[32]

 

CYP27A1

rs59443548

rs11559242

rs6994547

CYP7B1

rs5935258

rs8192907

170 asthmatic individuals and 174 healthy individuals/ Center region

 

Master’s Thesis

Only Genotyping

Determine the genotypic and allele frequencies of the repeat polymorphism in intron 4 of eNOS and of nucleotide substitution polymorphisms in amino acid 16 and 27 of ADRẞ2 in individuals suffering from asthma.

Predict a possible association between the studied genotypes and the development of the disease.

not specified

ADRẞ2

Arg16Gly

Gln27Glu

 

 

 

Asthma

It was found an association between the 27bp repeat polymorphism of the eNOS gene and susceptibility to asthma.

The prevalence of the Arg and Gly alleles of the ADRẞ2 Arg16Gly polymorphism in asthmatics is 68.3% and 31.7%, respectively.

In the ADRẞ2 Gln27Glu polymorphism, the prevalence in mutated allele (Glu) in asthma patients is higher than in the wild allele (Gln).

No association was found between eNOS or ADRβ2 polymorphisms and response to therapeutics.

[49]

eNOS

Master’s Thesis

 

Revision work about the importance of pharmacogenetics in rheumatoid arthritis.

Identified the main polymorphisms that may influence the efficacy, safety and applicability of this knowledge in clinical practice.

Immunosuppressants

 

Rheumatoid arthritis

Clinical pharmacogenetic testing is used only with AZA. The SSZ genotyping has the potential to identify patients with greater susceptibility to toxicity.

More studies are needed for the methotrexate and biological agents in order to clarify the mixed and contradictory results of the current studies.

[50]

antirheumatic agents

anti-TNF

azathioprine

methotrexate

sulfasalazine

300 healthy individuals /Center region

 

Original article

To characterize CYP2D6 polymorphisms and predict metabolic profiles in the Portuguese population.

not specified

CYP2D6*1

CYP2D6*2

CYP2D6*4

CYP2D6*10

 

 

Drug metabolism

Higher frequency of CYP2D6*10, and lower frequency of CYP2D6*6, and duplication of *1 and *2 compared to European population.


Important data in terms of effectiveness and safety in the exposure to xenobiotics, and in personalized pharmacotherapy.

[33]

Master’s Thesis

 

Revision work about the studies that demonstrate the influence of polymorphisms in the treatment of tuberculosis, aimed at the Caucasian / Portuguese population.

not applied

CYP2E1

GSTM1

GSTT1

Tuberculosis

The genotyping of certain enzymes may bring benefits not only in reducing complications and side effects, but in reducing appointments and hospitalizations.

[51]

 

101 patients

 

Madeira region

 

Doctoral Thesis

 

 

Analysis of multiple environmental factors assessed by questionnaire and the genotyping of SNPs IL131c.144 G/A, IL41590 C/T, IL41RP2 253183, ADRB21c.16 A/G, ADAM33-V4 C/G, ADAM33-S1 c.710 G/A, GSDML1236 C/T and STAT6121 C/T in a sample of Madeiran asthmatic patients and their families, and their association to asthma susceptibility and severity was assessed.

not applied

IL131-c.144 G/A

IL4-590 C/T

IL4RP2 253183

ADRB2-c.16 A/G

ADAM33-V4 C/G

ADAM33-S1 c.710 G/A

GSDML-236 C/T

STAT6-21 C/T

Asthma

IL41590*T, IL41RP2*183 as well as the combined genotypes IL41590*CT/IL41590*TT and IL41RP2*253183/IL41RP2*253183 were associated to both asthma susceptibility and severity.

GSDML1236*TT was found associated only to asthma severity.

ADAM331-V4*C was significantly over transmitted to asthmatic offspring being linked with the disease.

The findings suggest that in addition to environmental influences, IL41590 C/T, IL41RP2 253183, ADAM331V4 C/G and GSDML1236 C/T SNPs may constitute important genetic factor contributing to asthma susceptibility and/or severity in Madeira population.

 

[52]

25 patients / not specified

 

Original article

Only Genotyping

To study the association of HLA-B*58:01 with allopurinol-induced sCADR in a Portuguese population.

Antigout preparations

HLA-B*58:01

 

 

 

DRESS

SJS / TEN

 

 

HLA-B*58:01 was present in 16 patients with sCADR (64%) [12 DRESS (63%), four SJS/TEN (67%)], one allopurinol-tolerant individual (4%) and 63 normal controls.

When compared with the normal population, HLA-B*58:01 was associated with a higher risk of sCADR, both DRESS and SJS/TEN.

There was no statistically different risk between the 2 types of CADR.

Portuguese patients with sCADR from allopurinol, both DRESS and SJS/TEN, have a high frequency of HLA-B*58:01, with an OR similar to European patients with SJS/TEN.

[34]

Allopurinol

 

 

 

 

Master’s Thesis

A bibliographic review focus on pharmacogenetics and HIV therapy, looking closely at several types of antiretroviral drugs: the nucleotide reverse transcriptase inhibitors, the non-nucleotide reverse transcriptase inhibitors and the protease inhibitors and the way that several genes change the therapeutical response.

Antiretrovirals

 

HIV therapy

There is still a large amount of information that needs to be investigated and understood in relation to the possible interactions between genotypes, pharmacokinetics and pharmacodynamics of antiretrovirals.

Genetic variants are responsible for inter-individual variability, regarding the effectiveness of antiretroviral treatment and in the emergence of adverse reactions.

[62]

CCR5 antagonists

Fusion inhibitors

Integrase inhibitors

 

 

116 patients

70 Portuguese non-Gypsy (control group)

 

 / not specified

 

Master’s Thesis

 

Only Genotyping

To characterise a sample of Portuguese Gypsies for a selected panel of SNPs in genes with pharmacogenetic relevance, and to compare the derived pharmacogenetic profile with that of the Portuguese host population.

not specified

CYP2C9

rs1799853

rs1057910

 

 

 

 

Drug metabolism

For the screened variations no departures from Hardy-Weinberg equilibrium were detected in the Portuguese Gypsy and Portuguese non-Gyspy populations.

No major differences were detected in the results of the 2 populations.

[55]

CYP2C19

rs4244285

NAT2

rs1041983

rs1801280

TPMT

rs1800462

rs1800460

rs1142345

rs56161402

VKORC1

rs9923231

51 patients / Centre

 

 

Master’s Thesis

 

Only Genotyping

To characterize a sample of Portuguese diabetic individuals, through survey of a single nucleotide polymorphisms set identified in the literature and databases (related to pharmacogenetics of DM2 in coding region and for the European population (EUR)), followed by a correlation of the results with the drugs administered to individuals in the sample.

To propose a set of SNPs candidates for pharmacogenetics of DM2.

 

Sulphonylureas Glibenclamida

Gliclazida

Glimepirida

Sulphonylureas

Tolbutamida

 Tolbutamida

ABCC8

rs1799859

rs1801261

 

 

 

 

 

Diabetes Mellitus type 2 (DM2)

There were identified SNPs associated with pharmacogenetics of DM2 in scientific articles and databases, where a total of 98 SNPs were identified.

The SNPs were filtered for those in the coding region and associated with the EUR population.

Sixteen SNPs were observed in 10 genes in the 51 patients.

Correlation of drugs administered in the sample in study with the results from the survey of these SNPs, indicated that individuals carrying the SNPs rs12208357, rs34130495 and rs3405950 (SLC22A1) needed a higher dose of metformin, the carriers of SNP rs1801282 (PPAR) needed tighter control treatment metformin (given the increased risk of failure for this treatment) and carriers of SNP rs5219 (KCNJ11) needed a higher dose of gliclazide.

It was proposed a set of potential SNPs candidates for future studies concerning the pharmacogenetics of DM2 in the Portuguese population 32 SNPs located in the coding region and not yet referenced in the EUR population were selected from the set of 98 SNPs.

Additional 15 SNPs not yet related to the DM2 were also identified in the 51 patients.

[53]

CYP2C9

 

rs1799853

rs1057910

IRS1

rs1801278

KCNJ11

rs5219

Meglitinides

 

Repaglinida

Nateglinida

 

CYP2C8

rs10509681

rs11572080

CYP2C9

rs1057910

SLCO1B1

rs4149056

rs2306283

Thiazolidinediones

 

Rosiglitazona

Pioglitazona

CYP2C8

rs10509681

rs11572080

Biguanides

 

Metformina

 

SLC22A1

rs72552763

rs35167514

rs12208357

rs34130495

rs34059508

rs1867351

PPARγ

rs1801282

Inibitors of α glicosidase

 

Acarbose

PGC-1α (PPARGC1A)

rs8192678

 

GLP-1 and analogues

 

GLP-1

THADA

rs7578597

Master’s Thesis

 

A review work that aimed at present an overview on the state of the art of pharmacogenomics, with the introduction of its basic concepts, how genetic polymorphisms may modulate individual’s susceptibility to certain diseases or influences the therapeutic efficacy and safety of drugs.

not applied

 

 

It was concluded that Pharmacogenomics has reached a state in which it makes possible, if not an individual tuning of the pharmaceutical regímen, at leats the definition of groupings of individuals with similar genetic profiles and a corresponding more homogeneous response to drugs.

[54]

242 patients

 

/Center

 

Original article

Only Genotyping

To identify clinical and/or genetic predictors of response to several therapies in Crohn’s disease (CD) patients.

Immunosuppressants

ABCB1 C3435T, G2677T/A IL23R G1142A

C2370A

G9T

CASP9 C93T

Fas G670A

LgC844T

ATG16L1 A898G

 

 

 

 

 

 

Crohn’s disease

Older patients responded better to 5-aminosalicylic acid (5-ASA) and to azathioprine while younger ones responded better to biologicals.

Previous surgery negatively influenced response to 5-ASA compounds but favoured response to azathioprine.

Heterozygotes for ATGL16L1 SNP had a significantly higher chance of responding to corticosteroids, while homozygotes for Casp9 C93T SNP had a lower chance of responding both to corticosteroids and to azathioprine.

TT carriers of ABCB1 C3435T SNP had a higher chance of responding to azathioprine, while carriers of ABCB1 G2677T/A SNP, as well as responding better to azathioprine, had a lower chance of responding to biologicals, which became significant after adjusting for gender.

[35]

 

Azathioprine

Biologicals

 

Corticosteroids

 

 

 

 

 

 

 

Cohort

 

Original article

To elucidate the role of methylenetetrahydrofolate reductase (MTHFR) C677T and aminoimidazole carboxamide adenosine ribonucleotide transformylase (ATIC) T675C polymorphisms and clinicopathological variables in clinical response to MTX in Portuguese rheumatoid arthritis (RA) patients.

Methotrexate

MTHFR C677T

ATIC T675C

Rheumatoid Arthritis

MTHFR 677TT and ATIC 675T carriers were associated with over 4-fold increased risk for nonresponse.

For clinicopathological variables, noncurrent smokers, patients positive to anti-cyclic citrullinated peptide and antinuclear antibodies, with higher health assessment questionnaire score, and nonsteroidal anti-inflammatory drug users were also associated with nonresponse.

Subcutaneous administration route was associated with response.

MTHFR C677T and ATIC T675C genotyping combined with clinicopathological data may help to identify patients who will not benefit from MTX treatment and, therefore, assist clinicians in personalizing RA treatment.

[36]

233 Caucasian /

North region

Original article

To elucidate the influence of TYMS polymorphisms in MTX therapeutic outcome (regarding clinical response and toxicity) in Portuguese RA patients.

Methotrexate

TYMS

rs34743033

rs2853542

rs34489327

Rheumatoid Arthritis

TYMS polymorphisms could be important to help predicting clinical response to MTX in RA patients.

Translation into clinical practice needs larger studies to confirm the evidences.

[37]

233 patients

North region

Original article

 

To evaluate the influence of single nucleotide polymorphisms (SNPs) in genes encoding for MTX transporters with the occurrence of MTX-related toxicity (overall and gastrointestinal).

Methotrexate

SLC16A7

rs3763980

rs10877333

Rheumatoid Arthritis

SLC19A1, SLC46A1 and SLCO1B1 genotypes may help to identify patients with increased risk of MTX-related overall toxicity and that SLC19A1 and SLCO1B1 genotypes, and SLC19A1 haplotypes may help to identify patients with increased risk of MTX-related gastrointestinal toxicity.

[38]

SLC19A1

rs7499

rs1051266

rs2838956

rs3788200

SLC22A6

rs11568626

SLC22A11

rs11231809

SLC46A1

rs2239907

SLCO1B1

rs4149056

ABCB1

rs1045642

rs1128503

rs2032582

ABCC1

rs35592

rs246240

rs2074087

rs2230671

rs3784864

ABCC2

rs717620

rs4148396

ABCG2

rs2231142

rs13120400

rs17731538

Master’s Thesis

 

 

 

A review work about Pharmacogenomics of addiction

not applied

SNP

VNTR

Drug addiction

Drug addiction remains an unsolved health issue and has limited treatment options currently available.

The existing medications were not developed having a thorough knowledge of genetic and neurobiological causes of the disease.

More replication data is needed concerning some genetic variants to allow the identification of functional variants, but also the need for larger population samples has become clear for detecting small effect variants from the many genes accountable for addiction.

[56]

Master’s Thesis

A bibliographic review on pharmacogenetics in the treatment of breast cancer.

To study of the influence that genetic polymorphisms of metabolic enzymes, efflux transporters and estrogen receptors, have on response to tamoxifen therapy for breast cancer

not applied

CYP2C19*2

CYP2C19*17

CYP3A4

CYP3A4*22

CYP3A4*1B

CYP3A5

SULT1A1

SULT1A1*2

Breast cancer

Studies that analysed the role of CYP2D6 genotype in response to tamoxifen are controversial, most of these argue that poor metabolizers and intermediate have worse results than extensive metabolizers, although in only one of the studies with higher impact the same association was observed.

In the CYP3A4, the T allele for the CYP3A4*22 polymorphism was associated with higher concentration of tamoxifen and its metabolites and CYP3A4*1B polymorphism was associated with increased risk of developing endometrial cancer.

The polymorphisms at the estrogen receptors have demonstrated an important role in modulating the response to tamoxifen treatment on regards secondary and adverse effects. Larger population and greater control over variables are needed to reach a personalized medicine.

[57]

Lisbon

Porto

Coimbra

Master’s Thesis

Evaluation of pharmacogenomics in Portuguese clinical practice, identification of the skills and techniques for the application of pharmacogenomics and the potential areas of pharmacogenomics in clinical practice.

Azathioprine

not specified

Oncology and

infectious diseases

 

Pharmacogenomics/genetics in Portugal has some degree of weakness; is not a routine in clinical practice, not well known among professionals, genetics is not mainly use for therapeutic purposes.

The service of IPO Lisbon uses de detection of Human Epidermal growth factor Receptor-type 1 (HER1) for specific therapeutics of breast cancer.

[58]

Original article

 

To revise the major definitions in the pharmacogenetics as well as some classic examples of its application (related to cytochrome P450 genes, NAT2 gene and the Cholinesterase gene; the multitude of existing drug targets, like in case of G6PD gene, and the VKORC1 gene).

not applied

P450 genes

NAT2

G6PD VKORC1

not applied

Pharmacogenetics contribute to the development of new drugs, since it gives an important data, namely the knowledge of the potential variability associated with metabolization and/or action of the drug.

In addition, pharmacogenetics also plays an important role in reducing the number of patients who must participate in clinical trials, and potentially reduce the risk of failure in the lead-up stages in the market.

[39]

52 individuals with a suggestive phenotype of

trimethylaminuria and 100 healthy individuals/ not specified

 

Original article

Only Genotyping

Portuguese patients with phenotype suggestive of TMAu were evaluated for molecular screening of the FMO3 gene.

not specified

 

FMO3

 

 

 

TMAu

Identification of 32 variants in the FMO3 coding region.

P.Glu158Lys and p.Glu308Gly polymorphisms, in combination with other variants, originate different phenotypic patterns, which may lead to an abnormal drug metabolism in the liver and other organs and tissues.

[40]

 

 

208 patients / South region

 

Original article

 

Genotyping and drug testing

 

 

 

 

 

To assess the pharmacogenetic profile of a South Portuguese population according

to established dosing guidelines for commonly prescribed drugs and to compare it with that of previously genotyped populations.

Thiopurines

Clopidogrel

Warfarin

Fluoropyrimidines

Irinotecan

Codeine

Tricyclics

ABCB1

rs1045642

rs1128503

rs2032582

Drug metabolism

 

It was found a significant small differentiation between the Portuguese regional populations regarding CYP2C9 rs1057910, CYP2D6 rs3892097, MTHFR rs1801133 and F5 rs6025.

When considering 4 HapMap populations, ADH1B rs2066702, ADH1B rs1229984, NAT2 rs1799931 and VKORC1 rs9923231 displayed a significant population differentiation.

18.9% of the participants are intermediate or poor metabolizers for at least 3 drugs simultaneously and that 84.6% of the participants have at least one therapeutic failure or ADR risk allele for the considered drugs.

There is a high prevalence of risk alleles associated with an altered drug metabolism regarding drugs largely used by the South Portuguese population.

[41]

 

ADH1B

rs1229984

ADH1C

rs698

ADRB2

rs1042714

COMT

rs4680

CYP2C19

rs4244285

rs4986893

CYP2C8

rs11572080

CYP3A5

rs776746

CYP2D6

rs3892097

DPYD

rs67376798

rs1801265

rs55886062

F5

rs6025

GSTP1

rs1695

KCNJ11

rs5219

TPMT

rs1800462

rs1800460

rs1800584

rs1142345

233 patients /North

 

Original article

 

Genotyping and drug testing

 

 

Clinicopathological data from rheumatoid arthritis patients treated with methotrexate were collected, clinical response defined, and patients genotyped for 23 single nucleotide polymorphisms.

Genotype and haplotype analyses were performed using multivariate methods and a genetic risk index for non-response was created

Immunosuppressants

Antimetabolites

SLC16A7

rs3763980

rs10877333

 

 

 

Rheumatoid Arthritis

Genetic polymorphisms in SLC22A11 and ABCC1 could be predictors of clinical response to methotrexate in Portuguese rheumatoid arthritis patients.

Genotyping patients according to these genetic markers may be helpful to identify which patients will not benefit from methotrexate treatment, highlighting the relevance of developing the field of personalized medicine.

[42]

Methotrexate; Methotrexate + drug panel

SLC19A1

 

rs7499

rs1051266

rs2838956

rs3788200

SLC22A11

rs11231809

SLC46A1

rs2239907

SLCO1B1

rs4149056

167 patients

Original article

 

Genotyping and drug testing

 

To evaluate the repercussion of personalization of INH dosing by NAT2 genotyping in the management of tuberculosis patients.

To assess the role of other candidate genes like CYP2E1, GSTM1 and GSTT1 encoding detoxifying enzymes, and ABCB11, encoding a protein involved in bile salt transport.

 

 

Antimycobacterials

NAT2 

CYP2E1

GSTM1

GSTT1

ABCB11

 

 

 

 

 

Tuberculosis

Clinical variables such as gender and age were not associated with the occurrence of INH-induced hepatitis.

Slow acetylators (52.3%), identified by NAT2 genotyping, were significantly more prone to develop, as well as homozygous for variant Ala of ABCB11 polymorphism (rs2287622).

The presence of both risk genotypes was also significantly associated with increased susceptibility to hepatotoxicity.

Risk genotypes were frequent among patients: 52% of SA (NAT2), 32% of Ala/Ala (ABCB11) and 21% with both risk genotypes.

[43]

 

Isoniazid

 

 

 

 

 

 

Master’s Thesis

To develop a Sanger sequencing methodology for CYP2D6 gene to identify genetic variants that cause absence of enzyme activity and its application to post-mortem cases with tramadol

Tramadol

CYP2D6

 

 

The methods were successfully applied to post mortem blood samples.

Alleles and genotype frequencies were in accordance with the expected for European population.

Tramadol metabolism, expressed as its metabolites concentration ratio (N-desmethyltramadol/O-desmethyltramadol), has been shown to be correlated with the predicted phenotypes based on genetic characterization.

This is presumably the first time that a CYP2D6 sequencing methodology is validated and applied to post-mortem samples, in Portugal.

[59]

56 Portuguese gypsies / not specified

 

Master’s Thesis

 

Only Genotyping

To characterize the Portuguese Roma for Single Nucleotide Polymorphisms (SNPs), relevant from the Pharmacogenetics point of view.

 

To evaluate if the Roma show any peculiarity regarding drug response, in comparison with the host population.

not specified

CYP2D6

rs1065852

rs28371706

rs61736512

rs3892097

s35742686

rs5030656

rs16947

rs28371725

rs59421388

rs1135840

 

 

 

 

Drug metabolism

 

 

For the variations studied, only one SNP revealed significant deviation from the Hardy – Weinberg expectation, even after the Bonferroni correction, which was the 4180 G>C.

Comparatively to the Portuguese host population, the Roma showed some differences, especially an increased frequency of the CYP2D6*4, an allele implying null enzymatic activity.

Regarding the theoretical metabolic profiles, differences were found, especially the IM and PM profiles.

[60]

1688 patients / North, Centre, South regions

 

Original article

 

Genotyping and drug testing

 

To determine the prevalence of genotypes associated with a lower efficacy or a higher risk of adverse side effects in the treatment with statins in the Portuguese population.

Several SNPs involved in the metabolism, absorption, transport and/or excretion of the various types of statins were genotyped.

Statins

 

SLCO1B1

rs4149056

 

 

 

 

Dyslipidaemia

The SLCO1B1*5 variant, associated with an increased risk of developing myopathy on simvastatin treatment, has a frequency 2 times higher in the sample than described in the population databases. This fact, coupled with the large increase in national consumption of statins, mainly simvastatin, is an important factor that should be considered in the decision-making of the prescription of antidislipidemics.

 

 

[44]

APOE

rs7412

ABCB1

rs2032582

KIF6

rs20455

HMGCR

rs17238540

POR

rs1057868

ABCB1

rs1045642

CYP3A5

rs776746

CYP2C9

rs1057910

Master’s Thesis

To relate the knowledge underlying the field of Pharmacogenetics with pharmaceutical activity in the hospital context, reviewing the most important topics in this area for hospital pharmaceutical practice.

not specified

 

Oncology

The pharmacist assumes a central role in the implementation of Pharmacogenetics in clinical practice, since is a health professional with basic knowledge important for understanding this area, having the duty to specialize and help to instruct the remaining members of the research team health about the correct interpretation of the results of pharmacogenetic tests and the best way to apply them.

[61]

Original article

To investigate the impact of CYP2D6 genotyping of the tamoxifen metabolizing enzymes in the clinical management of breast cancer patients.

Tamoxifen

CYP2D6

Breast cancer

Portugal presents an interesting case for comparison in international pharmacogenomics context. This is especially the case of CYP2D6 testing prior to tamoxifen therapeutics. This is because there are no implemented measures based on pharmacogenomics analysis prior to therapy. Changing clinical paradigms involves assessment of several factors and a country with a clinical context as that of Portugal might function as a sample control in such analysis.

[46]

Original article

 

Genotyping and drug testing

 

To report on the real-life experience of 2 Portuguese dermatology departments with ustekinumab in patients with moderate to severe psoriasis.

To identify the clinical characteristics associated with a weaker clinical response.

Immunosuppressants

HLACw*0602

 

 

 

 

Psoriasis

A PASI75 therapeutic response was observed in 67.2%, 85.3%, 89.6% and 88.7% of patients at weeks 4, 12, 24 and 52, respectively.

Neither cardiovascular events nor cases of reactivation of previous infections (tuberculosis, hepatitis B) were observed during follow-up.

The therapeutic response was higher in patients naïve to biologic therapies as compared to non-naïve patients.

A trend towards lower clinical response was observed in patients weighing between 90-100 kg, and dosage optimization in these patients may be of value prior to considering biologic switch.

[45]

Ustekinumab

 

 

 

 

Table 2. Summary of study strategies (N=34)

Type of study

n

%

Cohort

15

44

Review

8

24

Genotype-based screening

6

18

Randomized controlled trial

5

15

Time horizon

 

 

Lifetime

0

0,0

≥20 years

0

0,0

3-10 years

4

11,8

≤3 years

3

8,8

No statement

27

79,4

Patient age range

 

 

≥ years

1

2,9

< 60 years

9

26,5

Not stated or not applicable

24

70,6

Pharmacogenomics approach

 

 

Study focused only on genetic/genomic testing

17

50,0

Genotyping and drug testing

9

26,5

None of the above

8

23,5

Table 3. Summary of study strategies (N=34)

Drug

Category

n

%

Methotrexate; Methotrexate + drug panel

Immunosuppressants; Antimetabolites

7

20,6

Clopidogrel, Warfarin

Antithrombotic agents

2

5,9

 Azathioprine, Biologicals, Corticosteroids

Corticosteroids, Immunosuppressants; biologics

1

2,9

Allopurinol

Antigout preparations

1

2,9

Azathioprine, Sulfasalazine, Methotrexate, Biological agents

Immunosuppressants; Intestinal anti-inflammatory agents; Antimetabolites; Biologics

1

2,9

Biguanides, Meglitinides, Sulphonylureas, Thiazolidinediones

Blood glucose lowering drugs

1

2,9

Codeine

Anti-infectives

1

2,9

Fusion inhibitors, CCR5 antagonists, Integrase inhibitors

Antiretrovirals

1

2,9

Isoniazid

Antimycobacterials

1

2,9

Risperidone

Psycholeptics, Antipsychotics

1

2,9

Statins

Lipid modifying agents

1

2,9

Tamoxifen, Irinotecan

 Antineoplastic and Immunomodulating agents

1

2,9

Tramadol

Analgesics

1

2,9

 Ustekinumab

Immunosuppressants

1

2,9

 not specified

13

38,2

Table 4. Summary of study characteristics (N=34)

Year

n

%

2007-2010

4

11,8

2011-2014

21

61,8

2015-2018

9

26,5

Portuguese region

 

 

North

3

8,8

Centre

4

11,8

South

1

2,9

Azores

1

2,9

Madeira

1

2,9

Not specified or not applicable

24

70,6

Disease indication or condition

 

Rheumatoid Arthritis

5

14,7

Breast Cancer

3

8,8

Asthma

2

5,9

Tuberculosis

2

5,9

Cardiovascular diseases

2

5,9

Autism

1

2,9

Crohn’s disease

1

2,9

Diabetes mellitus type 2

1

2,9

Drug addiction

1

2,9

DRESS; Stevens–Johnson Syndrome (S-JS) / Toxic Epidermal Necrolysis (TEN)

1

2,9

HIV

1

2,9

Leukemia

1

2,9

Lung cancer and Metastatic colorectal cancer

1

2,9

Psoriasis

1

2,9

Severe dyslipidemia

1

2,9

Trimethylaminuria

1

2,9

not specified

9

26,5