Genetic structure of pharmacogenetic biomarkers in Brazil inferred from a systematic review and population-based cohorts: a RIBEF/EPIGEN-Brazil initiative

Pharmacogenetic Testing in Treatment-resistant Panic Disorder: a Preliminary Analysis

Background

Many pharmacological treatments are considered effective in the treatment of panic disorder (PD), however, about 20 to 40% of the patients have treatment-resistant PD. Pharmacogenetics could explain why some patients are treatment-resistant.

Objective

Our objective was to gather preliminary data on the clinical usefulness of pharmacogenetic testing in this disorder.

Methods

Twenty patients with treatment-resistant PD were included in this observational study and submitted to commercial pharmacogenetic testing. Testing panel included gene polymorphisms related to CYP, genes EPHX1, UGT1A4, UGT2B15, ABCB1, ADRA2A, ANKK1, COMT, DRD2, FKBP5, GRIK4, GSK3B, HTR1A, HTR2A, HTR2C, MC4R, OPRM1, SCN1A, SLC6A4 and MTHFR. Participants received treatment-as-usual for PD before being enrolled in this study, including first-line and second-line medications for PD.

Results

In 30% of the patients, the tests indicated reduced chance of response to the prescribed drug, while they indicated very low serum levels of the prescribed drug in 20% of the subjects. The pharmacogenetic tests predicted reduction of MTHFR enzyme activity in 74% of the patients. ABCB1 gene alleles associated to drug resistance were found in 90% of the samples.

Conclusion

Commercial pharmacogenetic testing failed to predict negative treatment outcome in most patients with PD. The association between treatment-resistance in PD and the genes CYP2C19, MTHFR and ABCB1 deserves further study.

The Impact of TBXA2R Gene Variants on the Risk of Aspirin-Induced Upper Gastrointestinal Bleeding: A Case-Control Study

Objective: Upper gastrointestinal bleeding (UGIB) has been identified as a potential adverse drug reaction associated with the use of low-dose aspirin (LDA). This study aimed to investigate the relationship between variants in the TBXA2R gene, which is involved in platelet aggregation, and the risk of UGIB in patients with cardiovascular diseases treated with LDA. Methods: A case-control study was conducted at a Brazilian hospital complex. Three groups were defined: (1) case group (n = 50): patients with cardiovascular disease who used LDA and were diagnosed with UGIB of non-variceal etiology, (2) LDA control group (n = 50): patients with cardiovascular disease who used LDA without developing UGIB, and (3) healthy control group (n = 189). Data were collected through face-to-face interviews, and blood samples were collected for the analysis of Helicobacter pylori infection and genotyping of 3 genetic variants [rs2238631 (C > T), rs4807491 (A > G), and rs1131882 (A > G)]. Results: The case group had a significantly higher frequency of carriers of the rs4807491.G allele compared to the control group of LDA users (P-value = .004). No significant difference was observed in the proportion of carriers of the rs2238631.T and 1131882.G variants between the studied groups. Carriers of rs2238631.T (OR: 4.515, 95% CI: 1.37-14.89) and rs4807491.G allele (OR: 3.232, 95% CI: 1.12-9.37) exhibited a higher risk of UGIB. Conclusion: These findings suggest that the presence of the rs2238631 and rs4807491 variant alleles is associates with a 3- to 4-fold increased risk of UGIB in patients with cardiovascular diseases treated with LDA. Future studies with larger sample sizes should confirm these results and to better identify individuals who may benefit from chronic LDA use.

Unraveling the protective genetic architecture of COVID-19 in the Brazilian Amazon

Despite all the efforts acquired in four years of the COVID-19 pandemic, the path to a full understanding of the biological mechanisms involved in this disease remains complex. This is partly due to a combination of factors, including the inherent characteristics of the infection, socio-environmental elements, and the variations observed within both the viral and the human genomes. Thus, this study aimed to investigate the correlation between genetic host factors and the severity of COVID-19. We conducted whole exome sequencing (WES) of 124 patients, categorized into severe and non-severe groups. From the whole exome sequencing (WES) association analysis, four variants (rs1770731 in CRYBG1, rs7221209 in DNAH17, rs3826295 in DGKE, and rs7913626 in CFAP46) were identified as potentially linked to a protective effect against the clinical severity of COVID-19, which may explain the less severe impact of COVID-19 on the Northern Region. Our findings underscore the importance of carrying out more genomic studies in populations living in the Amazon, one of the most diverse from the point of view of the presence of rare and specific alleles. To our knowledge, this is the first WES study of admixed individuals from the Brazilian Amazon to investigate genomic variants associated with the clinical severity of COVID-19.

Influence of IL-β, IL-1RN, and TNF-α variants on the risk of acetylsalicylic acid-induced upper gastrointestinal bleeding: a case-control study

OBJECTIVE

Forgerini et al. investigated the role of seven genetic variants in the risk of upper gastrointestinal bleeding as an adverse drug reaction. In 289 participants (50 cases and 189 controls), the presence of seven variants in the IL-1β, IL-1RN, and TNF-α genes was not associated with susceptibility to acetylsalicylic acid-induced upper gastrointestinal bleeding. The use of acetylsalicylic acid, even in low doses, may be associated with the onset of upper gastrointestinal bleeding as an idiosyncratic response. Considering the role of the genetic background in inter-individual responses to pharmacotherapy, we aimed to investigate the role of seven variants in the TNF-α, IL-β, and IL-1RN genes in association with the risk of upper gastrointestinal bleeding in users of low-dose acetylsalicylic acid for the prevention of cardiovascular events.

METHODS

A case-control study was conducted in a Brazilian hospital complex. The Case Group comprised patients diagnosed with upper gastrointestinal bleeding who were administered a low dose of acetylsalicylic acid (n=50). Two Control Groups were recruited: 1) low-dose acetylsalicylic acid users without gastrointestinal complaints and under the supervision of a cardiologist (n=50) and 2) healthy controls (n=189). Sociodemographic, clinical, pharmacotherapeutic, and lifestyle data were recorded through face-to-face interviews. Genomic DNA from all participants was genotyped for rs16944 and rs1143634 (IL-β gene), rs4251961 (IL-1RN gene), and rs1799964, rs1799724, rs361525, and rs1800629 (TNF-α gene).

RESULTS

No significant difference was noted in the genotypic frequencies of TNF-α, IL-β, and IL-1RN variants between the Case and Control Groups of low-dose acetylsalicylic acid users (p>0.05). The frequency of rs1800629 genotypes (TNF-α gene) differed significantly between the Case Group and healthy controls (p=0.003). None of the evaluated variants were associated with a risk of upper gastrointestinal bleeding.

CONCLUSION

This study aimed to explore pharmacogenomics biomarkers in low-dose acetylsalicylic acid users. Our data suggest that the presence of IL-1β, IL-1RN, and TNF-α variants was not associated with an increased risk of upper gastrointestinal bleeding.

Psychiatric Level 1A evidence pharmacogenomics in a Brazilian admixed cohort and global populations

Purpose: To compare minor allele frequencies (MAFs) of psychiatric drug response variants in a Brazilian admixed cohort with global populations and other Brazilian groups. Methods: PharmGKB MAFs were gathered from publicly available genetic datasets for Brazil and worldwide. Results: Among 146 variants in CYP2D6 and CYP2C19, 41 were present in Brazil, mostly rare (MAF <1%). 11 variants showed significant MAF differences with large effect sizes compared with global populations. CYP2C19*3 (rs4986893), CYP2C19*17 (rs12248560), CYP2D6*17 (rs28371706-A) and CYP2D6*29 (rs61736512) exhibited higher frequencies in Brazil, with the latter three also differing from other Brazilian groups. Conclusion: This study highlights significant pharmacogenomic diversity in Brazil and globally, underscoring the need for more research in personalized psychiatric drug therapy.

Distribution of pharmacogene allele and phenotype frequencies in Brazilian psychiatric patients

Purpose: This work was designed to identify the pharmacogenetic profile of Brazilian psychiatric patients receiving psychoactive drug treatment according to ethnicity. Methods: Based on the GnTech® database, this cross-sectional study analyzed data from self-reported sociodemographic and genetic results from the next-generation sequencing panel composed of 26 pharmacogenes from 359 psychotropic drug users. Results: Variant frequencies of multiple pharmacogenes presented differences between ethnicities (CYP3A5, CYP2D6, CYP1A2, CYP2B6, CYP3A4, UGT1A4, UGT2B15, ABCB1 rs1045642, ADRA2A rs1800544, COMT rs4680, GRIK4 rs1954787, GSK3B rs334558, GSK3B rs6438552, HTR1A rs6295, HTR2A rs7997012, HTR2C rs1414334, MTHFR rs1801131, OPRM1 rs1799971 and 5-HTTLPR), endorsing the necessity of individual-level analyses in drug treatment. Conclusion: A discussion of pharmacogenomic test implementation in psychiatric clinical practice is needed to improve treatment choices, especially in Brazil, a multiethnic country.

Association of CYP2C19, CYP2D6 and CYP3A4 Genetic Variants on Primaquine Hemolysis in G6PD-Deficient Patients

In the Amazon, the treatment for Plasmodium vivax is chloroquine plus primaquine. However, this regimen is limited due to the risk of acute hemolytic anemia in glucose-6-phosphate dehydrogenase deficiency. Primaquine is a prodrug that requires conversion by the CYP2D6 enzyme to be effective against malaria. A series of cases were performed at an infectious diseases reference hospital in the Western Brazilian Amazon. The STANDARD G6PD (SD Biosensor^®) assay was used to infer G6PD status and real-time PCR to genotype G6PD, CYP2C19, CYP2D6 and CYP3A4. Eighteen patients were included, of which 55.6% had African A- variant (G202A/A376G), 11.1% African A+ variant (A376G), 5.6% Mediterranean variant (C563T) and 27.8% were wild type. CYP2C19, CYP2D6 and CYP3A4 genotyping showed no statistically significant differences in the frequency of star alleles between the groups G6PD deficient and G6PD normal. Elevated levels of liver and kidney markers in the G6PDd patients were observed in gNM, gRM and gUM of CYP2C19 and CYP2D6 (p < 0.05). Furthermore, in this study there was no influence of CYPs on hemolysis. These findings reinforce the importance of studies on the mapping of G6PD deficiency and genetic variations of CYP2C19, CYP2D6 and CYP3A4. This mapping will allow us to validate the prevalence of CYPs and determine their influence on hemolysis in patients with malaria, helping to decide on the treatment regimen.

Characterization of pharmacogenomic variants in a Brazilian admixed cohort of elderly individuals based on whole-genome sequencing data

Introduction: Research in the field of pharmacogenomics (PGx) aims to identify genetic variants that modulate response to drugs, through alterations in their pharmacokinetics (PK) or pharmacodynamics (PD). The distribution of PGx variants differs considerably among populations, and whole-genome sequencing (WGS) plays a major role as a comprehensive approach to detect both common and rare variants. This study evaluated the frequency of PGx markers in the context of the Brazilian population, using data from a population-based admixed cohort from Sao Paulo, Brazil, which includes variants from WGS of 1,171 unrelated, elderly individuals. Methods: The Stargazer tool was used to call star alleles and structural variants (SVs) from 38 pharmacogenes. Clinically relevant variants were investigated, and the predicted drug response phenotype was analyzed in combination with the medication record to assess individuals potentially at high-risk of gene-drug interaction. Results: In total, 352 unique star alleles or haplotypes were observed, of which 255 and 199 had a frequency < 0.05 and < 0.01, respectively. For star alleles with frequency > 5% (n = 97), decreased, loss-of-function and unknown function accounted for 13.4%, 8.2% and 27.8% of alleles or haplotypes, respectively. Structural variants (SVs) were identified in 35 genes for at least one individual, and occurred with frequencies >5% for CYP2D6, CYP2A6, GSTM1, and UGT2B17. Overall 98.0% of the individuals carried at least one high risk genotype-predicted phenotype in pharmacogenes with PharmGKB level of evidence 1A for drug interaction. The Electronic Health Record (EHR) Priority Result Notation and the cohort medication registry were combined to assess high-risk gene-drug interactions. In general, 42.0% of the cohort used at least one PharmGKB evidence level 1A drug, and 18.9% of individuals who used PharmGKB evidence level 1A drugs had a genotype-predicted phenotype of high-risk gene-drug interaction. Conclusion: This study described the applicability of next-generation sequencing (NGS) techniques for translating PGx variants into clinically relevant phenotypes on a large scale in the Brazilian population and explores the feasibility of systematic adoption of PGx testing in Brazil.

Worldwide Systematic Review of GSTM1 and GSTT1 Null Genotypes by Continent, Ethnicity, and Therapeutic Area

Glutathione S-transferase Mu 1 (GSTM1) and glutathione S-transferase theta 1 (GSTT1) enzymes are glutathione-S-transferases with broad significance for susceptibility or resistance to multifactorial human diseases, as well as detoxification of environmental chemicals and drugs. Moreover, some individuals may have a complete deletion of GSTM1 and GSTT1 genes, which can contribute to patient-to-patient variability in drug safety and efficacy. GSTM1 and GSTT1 gene deletion frequencies can vary according to ethnicity and continental origin of the studied population with implications for achieving the goal of precision/personalized medicine in clinical practice. We report here a worldwide systematic review of the null genotypes in these two clinically important genes by continents, ethnicities, and therapeutic areas (TAs). Searches were performed in the PubMed database covering the period from 1992 to 2020. Out of the 1925 articles included, most studies analyzed European individuals, corroborating the literature failure for not adequately considering the non-European ethnicities. The frequency of GSTM1 and GSTT1 null genotypes was higher in patients than in healthy volunteers. Conversely, in East Asians, higher frequencies of the null genotypes were observed in healthy volunteers than patients. Oncology was the most intensively studied TA (57% of the articles) in relation to GSTM1 and GSTT1. In all, these results demonstrate that there is an important gap in the literature in terms of failure to consider a broader range of populations, as well as diseases wherein GSTM1 and GSTT1 variations have clinical and biological implications. To achieve precision/personalized medicine on a global/worldwide scale, with equity and inclusiveness, this knowledge/research gap ought to be remedied in studies of GSTM1 and GSTT1 null genotypes. To the best of our knowledge, this is the largest systematic review conducted to date addressing the GSTM1 and GSTT1 null genotypes worldwide. The analyses from the 1925 articles highlighted the current knowledge gaps in different TAs, ethnicities, and populations. Filling these gaps is of importance, given the role these genes play in relation to the metabolism of substances to which we have frequent contact with, the associations observed between their deletion and diseases such as cancer, in addition to the interethnic differences observed for the deletion frequencies of these genes.

Reference values for left ventricular dimensions, systolic and diastolic function: a study from the Amazon Basin of Brazil

Country- and ethnicity-specific reference values for echocardiographic parameters are necessary for decision making. No prior studies have examined reference values in adults from the Amazon Basin of Brazil. We performed echocardiographic examinations in 290 healthy adults (mean age 37 ± 14 years, 40% male) from the Brazilian Amazon. Left ventricular (LV) dimensions and volumes were obtained and indexed to body surface area. We also assessed systolic (LV ejection fraction [LVEF] and global longitudinal strain [GLS]) and diastolic function. LV dimensions and volumes were larger in males compared to females, but after indexation only volumes remained larger (P < 0.001 for all). Parameters of systolic function, were significantly greater in females (LVEF 50 to 68%, GLS - 17 to - 24%) than in males (LVEF 50 to 67%, GLS - 15 to - 23%, P < 0.05). Upper limits of normality for cardiac dimensions (indexed and non-indexed) were markedly higher compared to contemporary guidelines (American Society of Echocardiography) and the Brazilian subgroup in the World Alliance Society of Echocardiography (WASE). Lower limit of normality for LVEF (both sex 50%) and upper limit of normality for the left atrial volume index (LAVI) (male: 31 mL/m2, female: 25 mL/m2) were within normal range but slightly lower compared to guidelines and the WASE study. Other diastolic parameters, including E/A-ratio, E/e' ratio and peak tricuspid regurgitation velocity were compatible with present recommendations. Normal reference ranges of echocardiographic parameters in healthy adults from the Brazilian Amazon Basin may be different compared to international guidelines and data from other regions of Brazil. This applies specifically for LVEF and LAVI.

Pharmacogenetics research in Brazil: a systematic review

Aim: Pharmacogenomics (PGx) is a rising scientific area in many countries, such as Brazil. Objectives: To identify biomarkers, therapeutic areas, probe drugs and regions/ethnicities most studied in the country in order to guide future studies. Materials & methods: Systematic review of 1060 studies (from 1968 to 2020) comprising 80 genes, six probe drugs and 3,819,233 individuals. Results: MTHFR and HLA-A/B were the most studied genes and metoprolol and dextromethorphan the most studied probe drugs. Oncology was the most studied therapeutic area considering PGx biomarkers. The country’s regions and ethnic groups were studied unevenly, with south/southeast and White people over-represented in respect to their demographic relevance, in detriment of the center-west/northeast/north and Black/mixed individuals. Conclusion: Many of the gaps and possible paths to be covered to reach even PGx data are pointed out by this review.

GSTM1 and GSTT1 polymorphisms in healthy volunteers - a worldwide systematic review

The GSTM1 and GSTT1 genes encode homonymous enzymes, which are responsible for the detoxification of several substances potentially harmful to the human body, such as air pollution, drugs, pesticides, and tobacco. However, some individuals may present a complete deletion of these genes and, consequently, an enzyme deficiency leading to an inadequate metabolism and, therefore, a higher susceptibility to some clinical conditions. Interethnic variations have also been described for both genes, making necessary the study of the deletion frequencies of GSTM1 and GSTT1 in different populations around the world. So, the aim of this study was to enable the synthesis and discussion of the main population differences of GSTM1 and GSTT1 polymorphisms in healthy volunteers. Searches were performed in the PubMed database, including 533 articles and 178,566 individuals in the analyses. We found an overrepresentation of European individuals and studies, and an underrepresentation of non-European ethnicities. Moreover, there are significant frequency differences among distinct ethnic groups: East Asians present the highest frequencies worldwide for GSTM1 and GSTT1 deletions, which could suggest higher disorders risk for this population; in contrast, Sub-Saharan Africans presented the lowest frequency of GSTM1 worldwide, corroborating evolution inferences performed previously for other genes codifying metabolism enzymes. Also, admixture is a relevant component when analyzing frequency values for both genes, but further studies focusing on this subject are warranted.

Perception and knowledge of pharmacogenetics among Brazilian psychiatrists

Pharmacogenetics (PGx) can optimize drug therapy in psychiatry and is particularly important in admixed populations. Here we developed and successfully validated a questionnaire for assessing the perception and knowledge of PGx among Brazilian psychiatrists. Overall, the participants showed some familiarity with PGx. Most psychiatrists reported to have knowledge of PGx and recognized its usefulness in psychiatry; however, they declared concerns regarding PGx education, the request of tests and their interpretation, cost-effectiveness, and ethical issues. PGx testing is relatively prevalent in their clinical practice, but education on the topic is lacking. Bivariate analysis revealed significant associations. Psychiatrists > 40 years of age more frequently had a positive perception of other clinicians' familiarity with PGx. Psychiatrists in private health services showed less self-reported competency in the use of PGx testing. Furthermore, women had better perception of PGx education. The present study adds knowledge about PGx in psychiatry and encourages the development of educational and training resources for PGx to improve its clinical implementation.

Pharmacogenomics of statins: lipid response and other outcomes in Brazilian cohorts

Statins are inhibitors of 3-hydroxy-3-methylglutaryl-CoA reductase, a key enzyme in cholesterol biosynthesis, that are highly effective in reducing plasma low-density lipoprotein (LDL) cholesterol and decreasing the risk of cardiovascular events. In recent years, a multitude of variants in genes involved in pharmacokinetics (PK) and pharmacodynamics (PD) have been suggested to influence the cholesterol-lowering response. However, the vast majority of studies have analyzed the pharmacogenetic associations in populations in Europe and the USA, whereas data in other populations, including Brazil, are mostly lacking. This narrative review provides an update of clinical studies on statin pharmacogenomics in Brazilian cohorts exploring lipid-lowering response, adverse events and pleiotropic effects. We find that variants in drug transporter genes (SLCO1B1 and ABCB1) positively impacted atorvastatin and simvastatin response, whereas variants in genes of drug metabolizing enzymes (CYP3A5) decreased response. Furthermore, multiple associations of variants in PD genes (HMGCR, LDLR and APOB) with statin response were identified. Few studies have explored statin-related adverse events, and only ABCB1 but not SLCO1B1 variants were robustly associated with increased risk in Brazil. Statin-related pleiotropic effects were shown to be influenced by variants in PD (LDLR, NR1H2) and antioxidant enzyme (NOS3, SOD2, MTHFR, SELENOP) genes. The findings of these studies indicate that statin pharmacogenomic associations are distinctly different in Brazil compared to other populations. This review also discusses the clinical implications of pharmacogenetic studies and the rising importance of investigating rare variants to explore their association with statin response.

EPIDEMIOLOGICAL PROFILE OF PATIENTS WITH NON-VARICEAL UPPER GASTROINTESTINAL BLEEDING SECONDARY TO PEPTIC DISEASE IN A TERTIARY REFERRAL BRAZILIAN HOSPITAL

BACKGROUND

Non-variceal upper gastrointestinal bleeding (NVUGIB) secondary to peptic ulcer disease is a medical digestive emergency and could be one of the most serious adverse drug reactions.

OBJECTIVE

To identify the frequency of diagnosis of NVUGIB secondary to peptic ulcer disease.

METHODS

Prospective and epidemiological study conducted in a tertiary referral Brazilian hospital, from July 2016 to December 2019. Upper gastrointestinal endoscopies (UGE) reports were evaluated daily. The diagnosis of NVUGIB secondary to peptic ulcer disease was defined through endoscopic findings of peptic ulcer and erosive gastric lesions, and clinical symptoms. The frequency of diagnosis of NVUGIB secondary to peptic ulcer disease was estimated through the ratio between the number of patients diagnosed and the number of patients underwent UGE in the same period.

RESULTS

A total of 2,779 endoscopic reports (2,503 patients) were evaluated, and 178 patients were eligible. The total frequency of diagnosis of NVUGIB secondary to peptic ulcer disease was 7.1%. The annual frequency of diagnosis between 2017 and 2019 ranged from 9.3% to 5.7%. Most patients were men (72.8%); self-declared white (71.8%); older people (56.7%); and, had no familiar or personal history of gastrointestinal diseases (60.1%). 90% of the patients had a peptic ulcer and melena (62.8%). Patients made chronic use of low-dose aspirin (29.3%), other antiplatelet agents (21.9%) and, oral anticoagulants (11.2%); and non-steroidal anti-inflammatories use in the week a prior to the onset of clinical symptoms (25.8%).

CONCLUSION

Seven in every 100 patients admitted and underwent UGE in a tertiary hospital were diagnosed with NVUGIB secondary to peptic ulcer disease.

Applying an equity lens to pharmacogenetic research and translation to under-represented populations

Since the publication of the Human Genome Project, genetic information has been used as an accepted, evidence-based biomarker to optimize patient care through the delivery of precision health. Pharmacogenetics (PGx) uses information about genes that encode proteins involved in pharmacokinetics, pharmacodynamics, and hypersensitivity reactions to guide clinical decision making to optimize medication therapy selection. Clinical PGx implementation is growing from the dramatic increase in PGx studies over the last decade. However, an overwhelming lack of genetic diversity in current PGx studies is evident. This lack of diverse representation in PGx studies will impede equitable clinical implementation through potentially inappropriate application of gene-based dosing algorithms, whereas representing a missed opportunity for identification of population specific single nucleotide variants and alleles. In this review, we discuss the challenges of studying PGx in under-represented populations, highlight two successful PGx studies conducted in non-European populations, and propose a path forward through community-based participatory research for equitable PGx research and clinical translation.

Genetic Variants in PTGS1 and NOS3 Genes Increase the Risk of Upper Gastrointestinal Bleeding: A Case-Control Study

Objective: To assess the association between PTGS1 and NOS3 variant alleles and the risk to develop upper gastrointestinal bleeding (UGIB) secondary to complicated peptic disease. Methods: A case-control study was conducted in a Brazilian complex hospital from July 2016 to March 2020. Case: Patients with UGIB diagnosis. Control: Patients admitted for surgery not related to gastrointestinal disorders. Variables: UGIB (outcome), genetic variants in PTGS1 and NOS3 genes (independent), and sex, age, schooling, ethnicity, previous history of gastrointestinal disorders, Helicobacter pylori serology, comorbidity, drug therapy, and lifestyle (confounding). The single-nucleotide polymorphisms (SNPs) of the PTSG1 gene (rs1330344, rs3842787, rs10306114, and rs5788) and NOS3 gene (rs2070744 and rs1799983) were determined using the real-time polymerase chain reaction. Helicobacter pylori serology was determined through the chemiluminescence technique. Logistic regression models were built and deviations of allelic frequencies from Hardy-Weinberg equilibrium were verified. Results: 200 cases and 706 controls were recruited. Carriers of the AG genotype of rs10306114 (OR: 2.55, CI 95%: 1.13-5.76) and CA + AA genotypes of rs5788 (OR: 2.53, CI 95%: 1.14-5.59) were associated with an increased risk for the UGIB development. In nonsteroidal anti-inflammatory drugs (NSAIDs) users, the six variants evaluated modified the magnitude of the risk of UGIB, whereas in low-dose aspirin (LDA) users, an increased risk of UGIB was observed for four of them (rs1330344, rs10306114, rs2070744, and rs1799983). Personal ulcer history (p-value: < 0.001); Helicobacter pylori infection (p-value: < 0.011); NSAIDs, LDA, and oral anticoagulant use (p-value: < 0.001); and alcohol intake (p-value: < 0.001) were also identified as independent risk factors for UGIB. Conclusion: This study presents two unprecedented analyses within the scope of the UGIB (rs10306114 and rs2070744), and our findings showing an increased risk of UGIB in the presence of the genetic variants rs10306114 and rs5788, regardless of the drug exposure. Besides, the presence of the evaluated variants might modify the magnitude of the risk of UGIB in LDA/NSAIDs users. Therefore, our data suggest the need for a personalized therapy and drug use monitoring in order to promote patient safety.

Metabolizer phenotype prediction in different Peruvian ethnic groups through CYP2C9 polymorphisms

OBJECTIVES

The CYP2C9 gene have three common alleles, CYP2C9*1, CYP2C9*2 and CYP2C9*3, associated with different homozygous (*1/*1, *2/*2 and *3/*3) and heterozygous (*1/*2 and *1/*3) genotypes, which in turn are related to extensive (gEM), intermediate (gIM) and poor (gPM) metabolizers. Likewise, the inter-ethnic variability was intimately associated with different drug metabolism. Therefore, the aim of the present study was predict the metabolizer phenotypes in different Peruvian ethnic groups from lowland (<2,500 m) and highland (>2,500 m).

METHODS

TaqMan genotyping assays were performed in a group of 174 healthy unrelated Peruvian individuals.

RESULTS

In this study, the allelic comparison between the three eco-regions showed that the CYP2C9*1 was the most common in Andean (96.32%); the *2 was the most frequent in Coast (7.45%, p<0.05). Regarding the *3 was the most common in Amazonian (6.25%, p<0.05). In a corroborative manner, the gEM was the most common in Andean (94.74%), the gIM in Coast (17.02%) and gPM in Amazonian (6.25%) populations.

CONCLUSIONS

Our study provides a valuable source of information about to metabolizer phenotype drugs in different Peruvian ethnic groups. In this way, it could be established suitable genetic-dosage medicaments for various common diseases in these heterogenetic populations.

Brazilian cohort and genes encoding for drug-metabolizing enzymes and drug transporters

Background & aim: Genetic variability in drug absorption, distribution, metabolism and excretion (ADME) genes contributes to the high heterogeneity of drug responses. The present study investigated polymorphisms of ADME genes frequencies and compared the findings with populations from other continents, available in the 1000 Genome Project (1 KGP) and the Exome Aggregation Consortium (ExAC) databases. Methodology & results: We conducted a study of 100 patients in Brazil and a total of 2003 SNPs were evaluated by targeted next-generation sequencing in 148 genes, including Phase I enzymes (n = 50), Phase II enzymes (n = 38) and drug transporters (n = 60). Overall, the distribution of minor allele frequency (MAF) suggests that the distribution of 2003 SNPs is similar between Brazilian cohort, 1 KGP and ExAC; however, we found moderate SNP allele-frequency divergence between Brazilian cohort and both 1000 KGP and ExAC. These differences were observed in several relevant genes including CYP3A4, NAT2 and SLCO1B1. Conclusion: We concluded that the Brazilian population needs clinical assessment of drug treatment based on individual genotype rather than ethnicity.

Tacrolimus therapeutic efficacy in post-liver transplant patients with Cytochrome P450 3A5 (CYP3A5) genetic polymorphisms

Genetic polymorphisms of CYP3A5 have been pointed out as factors that influenciates tacrolimus immunosuppressive efficacy in post liver transplant patients. This study aims to review the literature on the influence of cytochrome P450 3A5 (CYP3A5) genetic polymorphisms of tacrolimus in post-liver transplant patients. This study is a literature review. A combination of the descriptors "tacrolimus", "liver transplant", "cytochrome P-450 CYP3A inhibitors" and "genetic polymorphism" were used in the databases PubMed, Cochrane Library, Scopus and Scielo, being evaluated only studies between 2009 and 2019 in English, Portuguese or Spanish. A total of six studies, each from a different population were summarized. Initially, the pharmacological aspects of tacrolimus were discussed, including details on its pharmacodynamics, pharmacokinetics and toxicity After that, we analyzed the studies that correlates CYP3A5 genetic polymorphisms and tacrolimus efficacy, including the ethnical specifications and the general limittions of the studies. The CYP3A5 polymorphisms have pointed to alterations in the metabolism of tacrolimus according to the ethnic and populational genotype, specially the *1 and *3*3 alleles, reflecting in the need for dose adjustment and also in post liver transplant rejection.

Inconsistency in race and ethnic classification in pharmacogenetics studies and its potential clinical implications

Introduction

Racial and ethnic categories are frequently used in pharmacogenetics literature to stratify patients; however, these categories can be inconsistent across different studies. To address the ongoing debate on the applicability of traditional concepts of race and ethnicity in the context of precision medicine, we aimed to review the application of current racial and ethnic categories in pharmacogenetics and its potential impact on clinical care.

Methods

One hundred and three total pharmacogenetics papers involving the CYP2C9, CYP2C19, and CYP2D6 genes were analyzed for their country of origin, racial, and ethnic categories used, and allele frequency data. Correspondence between the major continental racial categories promulgated by National Institutes of Health (NIH) and those reported by the pharmacogenetics papers was evaluated.

Results

The racial and ethnic categories used in the papers we analyzed were highly heterogeneous. In total, we found 66 different racial and ethnic categories used which fall under the NIH race category “White”, 47 different racial and ethnic categories for “Asian”, and 62 different categories for “Black”. The number of categories used varied widely based on country of origin: Japan used the highest number of different categories for “White” with 17, Malaysia used the highest number for “Asian” with 24, and the US used the highest number for “Black” with 28. Significant variation in allele frequency between different ethnic subgroups was identified within 3 major continental racial categories.

Conclusion

Our analysis showed that racial and ethnic classification is highly inconsistent across different papers as well as between different countries. Evidence-based consensus is necessary for optimal use of self-identified race as well as geographical ancestry in pharmacogenetics. Common taxonomy of geographical ancestry which reflects specifics of particular countries and is accepted by the entire scientific community can facilitate reproducible pharmacogenetic research and clinical implementation of its results.

Polymorphisms of ADME-related genes and their implications for drug safety and efficacy in Amazonian Amerindians

The variation in the allelic frequencies of polymorphic pharmacogenes among different ethnic groups may be responsible for severe adverse reactions to or altered efficacy of a wide variety of drugs. Amazonian Amerindian populations have a unique genetic profile that may have a fundamental on the efficacy and safety of certain drugs. The genetic characteristics of these populations are poorly known, which can negatively impact the systematic application of treatments guided by pharmacogenomic guidelines. We investigated the diversity of 32 polymorphisms in genes responsible for drug Absorption, Distribution, Metabolism and Excretion (ADME) in Amazonian Amerindians, and compared the findings with populations from other continents available in the 1000 Genomes database. We found significantly different (P ≤ 1.56E-03) allelic frequencies and genotype distributions in many study markers in comparison with African, European, American and Asian populations. Based on FST values, the Amerindian population was also the most distinct (mean FST = 0.09917). These data highlight the unique genetic profile of the indigenous population from the Brazilian Amazon region, which is potentially important from a pharmacogenetic viewpoint. Understanding the diversity of ADME- related genetic markers is crucial to the implementation of individualized pharmacogenomic treatment protocols in Amerindian populations, as well as populations with a high degree of admixture with this ethnic group, such as the general Brazilian population.

Interethnic Variability in CYP2D6, CYP2C9, and CYP2C19 Genes and Predicted Drug Metabolism Phenotypes Among 6060 Ibero- and Native Americans: RIBEF-CEIBA Consortium Report on Population Pharmacogenomics

Pharmacogenetic variation in Latin Americans is understudied, which sets a barrier for the goal of global precision medicine. The RIBEF-CEIBA Network Consortium was established to characterize interindividual and between population variations in CYP2D6, CYP2C9, and CYP2C19 drug metabolizing enzyme genotypes, which were subsequently utilized to catalog their "predicted drug metabolism phenotypes" across Native American and Ibero American populations. Importantly, we report in this study, a total of 6060 healthy individuals from Ibero-America who were classified according to their self-reported ancestry: 1395 Native Americans, 2571 Admixed Latin Americans, 96 Afro-Latin Americans, 287 white Latin Americans (from Cuba), 1537 Iberians, and 174 Argentinean Ashkenazi Jews. Moreover, Native Americans were grouped into North-, Central-, and South Amerindians (from Mexico, Costa Rica, and Peru, respectively). All subjects were studied for the most common and functional CYP2D6, CYP2C9, and CYP2C19 allelic variants, and grouped as genotype-predicted poor or ultrarapid metabolizer phenotypes (gPMs and gUMs, respectively). Native Americans showed differences from each ethnic group in at least two alleles of CYP2D6, CYP2C9, and CYP2C19. Native Americans had higher frequencies of wild-type alleles for all genes, and lower frequency of CYP2D6*41, CYP2C9*2, and CYP2C19*17 (p < 0.05). Native Americans also showed less CYP2C19 gUMs than the rest of the population sample. In addition, differences within Native Americans (mostly North vs. South) were also found. The interethnic differences described supports the need for population-specific personalized and precision medicine programs for Native Americans. To the best of our knowledge, this is the largest study carried out in Native Americans and other Ibero-American populations analyzing CYP2D6, CYP2C9, and CYP2C19 genetic polymorphisms. Population pharmacogenomics is a nascent field of global health and warrants further research and education.