Influence of Genomic Ancestry on the Distribution of SLCO1B1, SLCO1B3 and ABCB1 Gene Polymorphisms among Brazilians

ABCB1 and OPRM1 single-nucleotide polymorphisms collectively modulate chronic shoulder pain and dysfunction in South African breast cancer survivors

Background: Chronic shoulder pain/disability is a well-recognized side effect of treatment for breast cancer, with ∼40% of patients experiencing this, despite receiving pain management. To manage acute and chronic pain, several opioids are commonly prescribed. Pharmacogenomics have implicated genes within the opioid signaling pathway, including ABCB1 and OPRM1, to contribute to an individual's variable response to opioids. Aim: To evaluate ABCB1 (rs1045642 G>A, rs1128503 G>A) and OPRM1 (rs1799971 A>G, rs540825 T>A) single-nucleotide polymorphisms (SNPs) in chronic shoulder pain/disability in BCS. Materials & methods: TaqMan^TM assays were used to genotype ABCB1 and OPRM1 SNPs within the BCS (N = 252) cohort. The Shoulder Pain and Disability Index was used to evaluate pain and disability features associated with shoulder pathologies. Participants end scores for each feature (pain, disability and combined [pain and disability]) were categorized into no-low (>30%) and moderate-high (≥30%) scores. Statistical analysis was applied, and significance was accepted at p < 0.05. Results: Of participants, 27.0, 19.0 and 22.0% reported moderate-high pain, disability and combined (pain and disability) scores, respectively. ABCB1:rs1045642-(A/A) genotype was significantly associated with disability (p = 0.028: no-low [14.9%] vs mod-high [4.3%]) and combined (pain and disability) (p = 0.011: no-low [15.9%] vs mod-high [5.7%]). The ABCB1:rs1045642-(A) allele was significantly associated with disability (p = 0.015: no-low [37.9%] vs mod-high [23.9%]) and combined (pain and disability) (p = 0.003: no-low [38.5%] vs mod-high [23.6%]). The inferred ABCB1 (rs1045642 G>A - rs1128503 G>A): A-G (p = 0.029; odds ratio [OR]: 0.0; 95% CI: 0.0-0.0) and the OPRM1 (rs1799971 A>G - rs540825 T>A): G-T (p = 0.019; OR: 0.33; 95% CI: 0.14-0.75) haplotypes were associated with disability and pain, respectively. Gene-gene interactions showed the ABCB1 (rs1045642 G>A) - OPRM1 (rs540825 T>A) combinations, (A-T) (p = 0.019; OR: 0.62; 95% CI: 0.33-1.16) and (G-A) (p = 0.021; OR: 1.57; 95% CI: 0.30-3.10) were associated with disability. Conclusion: The study implicated ABCB1 with shoulder pain and disability; and haplotype analyses identified specific genetic intervals within ABCB1 and OPRM1 to associate with chronic shoulder pain and disability. Evidence suggests that potentially gene-gene interactions between ABCB1 and OPRM1 contribute to chronic shoulder pain and disability experienced in this SA cohort.

Prevalence of protective haplotypes of the SLCO1B1 gene for statin transport in Mexican populations

Aim: To evaluate the genetic distribution of the rs4149056 and rs2306283 variants in the SLCO1B1 gene in Mexican Mestizo (admixed) and Native American groups. Materials & methods: We recruited 360 volunteers who were qPCR-genotyped with TaqMan probes. Results: Allele and genotype frequencies are reported. Among the expected rs4149056-rs2306283 haplotypes, T-A (42.35-58.47%) was the most prevalent which relates to the normal activity of the OATP1B1 transporter. This was followed by the T-G haplotype associated with further statin transport and cholesterol reduction (32.49-43.76%). Conclusion: Based on these SLCO1B1 gene variants, we confirmed that a minimum fraction of the Mexican study populations would be at risk from decreasing simvastatin transport and the development of statin-induced myopathy.

Impact of environmental changes on Dermatology

Urbanization, pollution and the modification of natural landscapes are characteristics of modern society, where the change in human relations with the environment and the impact on biodiversity are environmental determinants that affect the health-disease relationship. The skin is an organ that has a strong interface with the environment and, therefore, the prevalence patterns of dermatoses may reflect these environmental changes. In this article, aspects related to deforestation, fires, urbanization, large-scale agriculture, extensive livestock farming, pollution and climatic changes are discussed regarding their influence on the epidemiology of skin diseases. It is important that dermatologists be aware of their social responsibility in order to promote sustainable practices in their community, in addition to identifying the impacts of environmental imbalances on different dermatoses, which is essential for the prevention and treatment of these diseases.

Associations ofVEGFAandKDRsingle-nucleotide polymorphisms and increased risk and aggressiveness of high-grade gliomas

Angiogenesis, induced by the vascular endothelial growth factor A through its ligation to the vascular endothelial growth receptor 2, has been described as a crucial point in high-grade glioma development. The aim of this study was to evaluate the influence of VEGFA–2578C/A, −2489C/T, −1154G/A, −634G/C, and −460C/T, and KDR–604T/C, −271G/A, +1192G/A, and +1719A/T single-nucleotide polymorphisms on risk and clinicopathological aspects of high-grade glioma. This case–control study enrolled 205 high-grade glioma patients and 205 controls. Individuals with VEGFA–2578 CC or CA, VEGFA–1154 GG, VEGFA–634 GC or CC, and VEGFA–460 CT or TT genotypes were under 2.56, 1.53, 1.54, and 1.84 increased risks of high-grade glioma, compared to others, respectively. And 1.61, 2.66, 2.52, 2.53, and 2.02 increased risks of high-grade glioma were seen in individuals with VEGFA–2578 CC plus VEGFA–1154 GG, VEGFA–2578 CC or CA plus VEGFA–634 GC or CC, VEGFA–2578 CC or CA plus VEGFA–460 CT or TT, VEGFA–1154 GG or GA plus VEGFA–634 GC or CC, and VEGFA 634 GC or CC plus VEGFA–460 CT or TT combined genotypes, respectively, when compared to others. The “CAGT” haplotype of KDR single-nucleotide polymorphisms was more common in patients with grade IV than in those with grade III tumors, and individuals carrying this haplotype were at 1.76 increased risk of developing grade IV tumors than others. We present, for the first time, preliminary evidence that VEGFA–2578C/A and VEGFA–1154G/A single-nucleotide polymorphisms increases high-grade glioma risk, and “CAGT” haplotype of the KDR gene alters high-grade glioma aggressiveness and risk of grade IV tumors in Brazil.

Pharmacogenomics research and clinical implementation in Brazil

We searched PubMed entries and the Lattes database of Brazilian Pharmacogenetics Network investigators, for pharmacogenetic/genomic (PGx) studies in the Brazilian population, focusing on the drugs and genes included in the Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines. Warfarin was the most extensively studied drug in a PGx context: a genomewide association study targeting warfarin stable dose identified significant signals in VKORC1 and CYP2C9, several PGx dosing algorithms were developed based on these and other genes, and the implications of population admixture on extrapolation of dosing recommendations in the CPIC guidelines were examined. A study in renal transplanted patients disclosed association of CYP3A5*6 and CYP3A5*7 with tacrolimus dosing, which led to addition of these variants to CYP3A5*3 in the CPIC tacrolimus guideline. Studies verified predisposition of HIV-positive carriers of UGT1A1*28 to severe atazanavir-induced hyperbilirubinaemia, intolerance to 5-fluorouracyl in gastrointestinal cancer patients with deleterious DPYD variants, failure of HCV-infected carriers of IFNL3 rs12979860 to obtain a sustained viral response to PEG-IFN-α, and hypersensitivity reactions to abacavir in HIV-positive carriers of HLA-B*57:01. No prospective analyses of drug therapy outcomes or cost-effectiveness assessments of PGx-guided therapy were found. In conclusion, the limited adoption of PGx-informed drug prescription in Brazil reflects combination of recognized barriers to PGx implementation worldwide plus factors specific to the Brazilian population. The latter include rarity/absence of genetic variants on which international PGx guidelines are based (eg HLA-B*15.02 for phenytoin and carbamazepine) and the caveat of extrapolating to the admixed Brazilian population, guidelines based on categorical variables, such as continental ancestry (eg warfarin guidelines), "race" or ethnicity.

The potential European genetic predisposition for non-contact anterior cruciate ligament injury

PURPOSE

Previous research has provided evidence of a hereditary predisposition for anterior cruciate ligament (ACL) injury. The purpose of this study was to evaluate the association between ancestral population genetics and risk of non-contact ACL injuries.

METHODS

Blood samples were collected from 177 individuals with a history of non-contact ACL injury and 556 non-injured control individuals for analysis of the genetic material through the use of a panel of 48 INDELs ancestry genetic markers from three ancestral origins.

RESULTS

Among patients with non-contact ACL injury, 82% were male and 18% were female. In the control group, 78% were male, and 22% were female. The mean age of the non-contact ACL injury group was 31.7 years (± 10.2), and the control group was 33.8 years (± 13.2). The individual genetic contribution from INDELs of each ancestral origin varied considerably: ranging between 1.5-94.8% contribution for INDELs of African origin (mean of 21.4% of INDELs); between 2 and 96.1% contribution for INDELs of European origin (mean of 66.7% of INDELs); and between 1.3-96.4% contribution for INDELs of Amerindian origin (mean of 11.7% of INDELs). When comparing paired subjects from the non-contact ACL and control groups, the genetic analysis showed that the European ancestry score was higher in the non-contact ACL group than control group (0.70 ± 0.21 vs 0.63 ± 0.22 respectively, p < 0.001), whereas African ancestry scores (ACL group 0.18 ± 0.18 vs control group 0.24 ± 0.21, p < 0.001) and Amerindian ancestry scores (ACL group 0.11 ± 0.09 vs control group 0.12 ± 0.10, n.s.) were lower among the non-contact ACL group than in controls.

CONCLUSION

European INDELs markers were found to represent a potential genetic predisposition for non-contact ACL injuries when compared to African and Amerindian INDELs. This study has the potential to correlate a measurable and distinct genetic marker with risk of a non-contact ACL injury. Thus, it increases knowledge base and volume of molecular and genetical factors associated with this pathology. Furthermore, this study provides guidance and evidence for the development of genetic risk-screening panels for non-contact ACL injury.

LEVEL OF EVIDENCE

Level III Diagnostic Study.

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

We present allele frequencies involving 39 pharmacogenetic biomarkers studied in Brazil, and their distribution on self-reported race/color categories that: (1) involve a mix of perceptions about ancestry, morphological traits, and cultural/identity issues, being social constructs pervasively used in Brazilian society and medical studies; (2) are associated with disparities in access to health services, as well as in their representation in genetic studies, and (3), as we report here, explain a larger portion of the variance of pharmaco-allele frequencies than geography. We integrated a systematic review of studies on healthy volunteers (years 1968-2017) and the analysis of allele frequencies on three population-based cohorts from northeast, southeast, and south, the most populated regions of Brazil. Cross-validation of results from these both approaches suggest that, despite methodological heterogeneity of the 120 studies conducted on 51,747 healthy volunteers, allele frequencies estimates from systematic review are reliable. We report differences in allele frequencies between color categories that persist despite the homogenizing effect of >500 years of admixture. Among clinically relevant variants: CYP2C9*2 (null), CYP3A5*3 (defective), SLCO1B1-rs4149056(C), and VKORC1-rs9923231(A) are more frequent in Whites than in Blacks. Brazilian Native Americans show lower frequencies of CYP2C9*2, CYP2C19*17 (increased activity), and higher of SLCO1B1-rs4149056(C) than other Brazilian populations. We present the most current and informative database of pharmaco-allele frequencies in Brazilian healthy volunteers.

SLCO1A2, SLCO1B1 and SLCO2B1 polymorphisms influences chloroquine and primaquine treatment in Plasmodium vivax malaria

AIM

The association of transporters gene polymorphisms with chloroquine/primaquine malaria treatment response was investigated in a Brazilian population.

PATIENTS & METHODS

Totally, 164 Plasmodium vivax malaria infected patients were included. Generalized estimating equations were performed to determine gene influences on parasitemia and/or gametocytemia clearance over treatment time.

RESULTS

Significant interaction between SLCO2B1 genotypes and treatment over time for parasitemia clearance rate on day 2 were observed (p _FDR = 0.002). SLCO1A2 and SLCO1B1 gene treatment over time interactions were associated with gametocytemia clearance rate (p _FDR = 0.018 and p _FDR = 0.024). ABCB1, ABCC4 and SLCO1B3 were not associated with treatment response.

CONCLUSION

The present work presents the first pharmacogenetic report of an association between chloroquine/primaquine responses with OATP transporters.

Transporter genes ABCG2 rs2231142 and ABCB1 rs1128503 polymorphisms and atorvastatin response in Chilean subjects

WHAT IS KNOWN AND OBJECTIVE

Statins are first-line therapy for reducing high cholesterol levels. However, response to these drugs shows high interindividual variability. We aimed to investigate the influence of two single nucleotide polymorphisms (SNP) (ABCB1 rs1128503 and ABCG2 rs2231142) in the ABC transporter genes on response to short-term low-dose atorvastatin in Chilean hypercholesterolaemic patients.

METHODS

We studied 127 Chilean hypercholesterolaemic patients treated with 10 mg/d atorvastatin for 4 weeks. The lipid profile was determined before and after drug administration. Genotyping of the rs1128503 and rs2231142 variants was performed using TaqMan^® Drug Metabolism Genotyping Assays.

RESULTS AND DISCUSSION

Genotype distribution for all polymorphisms investigated was consistent with the Hardy-Weinberg equilibrium. Atorvastatin reduced TC, LDL-C and TG concentrations (P<.05), whereas HDL-C levels were found to be increased (P<.05). Minor allele frequencies for rs1128503 and rs2231142 variants were 0.453 and 0.075, respectively. In this study, patients prescribed with short-term low-dose atorvastatin and carrying ABCB1 (rs1128503) or ABCG2 (rs2231142) SNPs did not show differences in LDL-C response (P>.05).

WHAT IS NEW AND CONCLUSION

The ABCB1 SNP was not associated with response to atorvastatin in Chilean subjects. The few ABCG2 421A homozygotes did not allow meaningful inferences to be made for this polymorphism.

African ancestry is associated with facial melasma in women: a cross-sectional study

Background

Melasma is a chronic acquired focal hypermelanosis affecting photoexposed areas, especially for women during fertile age. Several factors contribute to its development: sun exposure, sex steroids, medicines, and family history. Melanic pigmentation pathway discloses several SNPs in different populations. Here, we evaluated the association between genetic ancestry and facial melasma.

Methods

A cross-sectional study involving women with melasma and an age-matched control group from outpatients at FMB-Unesp, Botucatu-SP, Brazil was performed. DNA was extracted from oral mucosa swabs and ancestry determined by studying 61 INDELs. The genetic ancestry components were adjusted by other known risk factors by multiple logistic regression.

Results

We evaluated 119 women with facial melasma and 119 controls. Mean age was 39 ± 9 years. Mean age at beginning of disease was 27 ± 8 years. Pregnancy (40%), sun exposure (37%), and hormonal oral contraception (22%) were the most frequently reported melasma triggers. All subjects presented admixed ancestry, African and European genetic contributions were significantly different between cases and controls (respectively 10% vs 6%; 77% vs 82%; p < 0.05). African ancestry (OR = 1.04; 95% CI 1.01 to 1.07), first generation family history (OR = 3.04; 95% CI 1.56 to 5.94), low education level (OR = 4.04; 95% CI 1.56 to 5.94), and use of antidepressants by individuals with affected family members (OR = 6.15; 95% CI 1.13 to 33.37) were associated with melasma, independently of other known risk factors.

Conclusions

Facial melasma was independently associated with African ancestry in a highly admixed population.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-017-0378-7) contains supplementary material, which is available to authorized users.

Neither self-reported ethnicity nor declared family origin are reliable indicators of genomic ancestry

Ancestry information can be useful in investigations of diseases with a genetic or infectious background. As the Brazilian population is highly admixed physical traits tend to be poor indicators of ancestry. The assessment of ancestry by ancestry informative markers (AIMs) can exclude the subjectivity of self-declared ethnicity and reported family origin. We aimed to evaluate the reliability of self-reported ethnicity or reported family origin as indicators of genomic ancestry in a female population from the Southeast of Brazil. Two cohorts were included: 404 women asked to self-report their ethnicity (Pop1) and 234 women asked to report their family's origin (Pop2). Identification of AIMs was performed using a panel of 61 markers and results were plotted against parental populations-Amerindian, Western European and Sub-Saharan African-using Structure v2.3.4. In Pop1 57.4 % of women self-reported as white, 34.6 % as brown and 8.0 % as black. Median global European, Amerindian and African contributions were 66.8, 12.6 and 16.6 %. In Pop2, 66.4 % of women declared European origin, 23.9 % African origin and 26.9 % Amerindian. Median global European, Amerindian and African contributions were 80.8, 7.3 and 7.6 %, respectively. Only 31.0 and 21.0 % of the global variation in African and European contributions, respectively, could be explained by self-reported ethnicity and reported family origin only accounted for 20.0 and 5.0 % of the variations observed in African and European ancestries, respectively. Amerindian ancestry did not influence self-reported ethnicity or declared family origin. Neither self-reported ethnicity nor declared family origin are reliable indicators of genomic ancestry in these Brazilian populations.

Misoprostol-induced fever and genetic polymorphisms in drug transporters SLCO1B1 and ABCC4 in women of Latin American and European ancestry

AIM

Misoprostol, a prostaglandin analogue used for the treatment of postpartum hemorrhage and termination of pregnancy, can cause high fevers. Genetic susceptibility may play a role in misoprostol-induced fever.

SUBJECTS & METHODS

Body temperature of women treated with misoprostol for termination of pregnancy in the UK (n = 107) and for postpartum hemorrhage in Ecuador (n = 50) was measured. Genotyping for 33 single nucleotide polymorphisms in 15 candidate genes was performed. Additionally, we investigated the transport of radiolabeled misoprostol acid across biological membranes in vitro.

RESULTS

The ABCC4 single nucleotide polymorphism rs11568658 was associated with misoprostol-induced fever. Misoprostol acid was transported across a blood-brain barrier model by MRP4 and SLCO1B1.

CONCLUSION

Genetic variability in ABCC4 may contribute to misoprostol-induced fever in pregnant women. Original submitted 21 January 2015; Revision submitted 24 April 2015.

Pharmacogenomics, human genetic diversity and the incorporation and rejection of color/race in Brazil

Public funding for research on the action of drugs in countries like the United States requires that racial classification of research subjects should be considered when defining the composition of the samples as well as in data analysis, sometimes resulting in interpretations that Whites and Blacks differ in their pharmacogenetic profiles. In Brazil, pharmacogenomic results have led to very different interpretations when compared with those obtained in the United States. This is explained as deriving from the genomic heterogeneity of the Brazilian population. This article argues that in the evolving field of pharmacogenomics research in Brazil there is simultaneously both an incorporation and rejection of the US informed race-genes paradigm. We suggest that this must be understood in relation to continuities with national and transnational history of genetic research in Brazil, a differently situated politics of Brazilian public health and the ongoing valorization of miscegenation or race mixture by Brazilian geneticists as a resource for transnational genetic research. Our data derive from anthropological investigation conducted in INCA (Brazilian National Cancer Institute), in Rio de Janeiro, with a focus on the drug warfarin. The criticism of Brazilian scientists regarding the uses of racial categorization includes a revision of mathematical algorithms for drug dosage widely used in clinical procedures around the world. Our analysis reveals how the incorporation of ideas of racial purity and admixture, as it relates to the efficacy of drugs, touches on issues related to the possibility of application of pharmaceutical technologies on a global scale.

Pharmacogenetics of coumarin anticoagulants in Brazilians

INTRODUCTION

Coumarin vitamin K antagonists are the mainstay of anticoagulant therapy in atrial fibrillation, prosthetic heart valves and thromboembolic conditions. Concerns with these drugs include large inter-individual variability in dose requirements, narrow therapeutic index and need to monitor prothrombin time repeatedly.

AREAS COVERED

Pharmacogenetic studies and dosing algorithms for warfarin and phenprocoumon.

EXPERT OPINION

Gene candidate studies in Brazilian patients verified consistently the association of warfarin and pheprocoumon stable dose requirements with CYP2C9 and VKORC1 polymorphisms, and minor or no influence of other pharmacogenes (e.g., CYP4F2 and F7). The predictive power of warfarin and phenprocoumon dosing algorithms developed for Brazilians compares favorably with those reported for other populations. A warfarin dosing algorithm derived for an admixed cohort performed equally well in self-reported White and Black patients, in marked contrast with the considerably poorer performance of other warfarin algorithms in patients of African descent compared to those of European ancestry. This discrepancy is ascribed to the extensive European/African admixture among Brazilians. Prospective studies of clinical utility of coumarin dosing algorithms, in the context of the Brazilian Public Health System, would represent an important counterpart to recently published trials in European and North American cohorts with predominant or exclusive European ancestry.

Distribution of CYP2D6 alleles and phenotypes in the Brazilian population

The CYP2D6 enzyme is one of the most important members of the cytochrome P450 superfamily. This enzyme metabolizes approximately 25% of currently prescribed medications. The CYP2D6 gene presents a high allele heterogeneity that determines great inter-individual variation. The aim of this study was to evaluate the variability of CYP2D6 alleles, genotypes and predicted phenotypes in Brazilians. Eleven single nucleotide polymorphisms and CYP2D6 duplications/multiplications were genotyped by TaqMan assays in 1020 individuals from North, Northeast, South, and Southeast Brazil. Eighteen CYP2D6 alleles were identified in the Brazilian population. The CYP2D6*1 and CYP2D6*2 alleles were the most frequent and widely distributed in different geographical regions of Brazil. The highest number of CYPD6 alleles observed was six and the frequency of individuals with more than two copies ranged from 6.3% (in Southern Brazil) to 10.2% (Northern Brazil). The analysis of molecular variance showed that CYP2D6 is homogeneously distributed across different Brazilian regions and most of the differences can be attributed to inter-individual differences. The most frequent predicted metabolic status was EM (83.5%). Overall 2.5% and 3.7% of Brazilians were PMs and UMs respectively. Genomic ancestry proportions differ only in the prevalence of intermediate metabolizers. The IM predicted phenotype is associated with a higher proportion of African ancestry and a lower proportion of European ancestry in Brazilians. PM and UM classes did not vary among regions and/or ancestry proportions therefore unique CYP2D6 testing guidelines for Brazilians are possible and could potentially avoid ineffective or adverse events outcomes due to drug prescriptions.

Global pharmacogenomics: distribution of CYP3A5 polymorphisms and phenotypes in the Brazilian population

The influence of self-reported "race/color", geographical origin and genetic ancestry on the distribution of three functional CYP3A5 polymorphisms, their imputed haplotypes and inferred phenotypes was examined in 909 healthy, adult Brazilians, self-identified as White, Brown or Black ("race/color" categories of the Brazilian census). The cohort was genotyped for CYP3A5*3 (rs776746), CYP3A5*6 (rs10264272) and CYP3A5*7 (rs41303343), CYP3A5 haplotypes were imputed and CYP3A5 metabolizer phenotypes were inferred according to the number of defective CYP3A5 alleles. Estimates of the individual proportions of Amerindian, African and European ancestry were available for the entire cohort. Multinomial log-linear regression models were applied to infer the statistical association between the distribution of CYP3A5 alleles, haplotypes and phenotypes (response variables), and self-reported Color, geographical region and ancestry (explanatory variables). We found that Color per se or in combination with geographical region associates significantly with the distribution of CYP3A5 variant alleles and CYP3A5 metabolizer phenotypes, whereas geographical region per se influences the frequency distribution of CYP3A5 variant alleles. The odds of having the default CYP3A5*3 allele and the poor metabolizer phenotype increases continuously with the increase of European ancestry and decrease of African ancestry. The opposite trend is observed in relation to CYP3A5*6, CYP3A5*7, the default CYP3A5*1 allele, and both the extensive and intermediate phenotypes. No significant effect of Amerindian ancestry on the distribution of CYP3A5 alleles or phenotypes was observed. In conclusion, this study strongly supports the notion that the intrinsic heterogeneity of the Brazilian population must be acknowledged in the design and interpretation of pharmacogenomic studies, and dealt with as a continuous variable, rather than proportioned in arbitrary categories that do not capture the diversity of the population. The relevance of this work extrapolates the Brazilian borders, and extends to other admixed peoples of the Americas, with ancestral roots in Europe, Africa and the American continent.

Polymorphic variants of SLCO1B1 in neonatal hyperbilirubinemia in China

Background

To evaluate the association between the genetic polymorphism of the solute carrier organic anion transporter family member 1B1 (SLCO1B1, also known as organic anion transport polypeptide C) and hyperbilirubinemia in Chinese neonates.

Methods

183 infants with hyperbilirubinemia and 192 control subjects from the Fifth People’s Hospital of Shenzhen were recruited. Polymerase chain reaction, restriction fragment length polymorphisms and agarose gel electrophoresis techniques were used to detect genetic variants of SLCO1B1.

Results

The study revealed that SLCO1B1 388 G > A occurred significantly more frequently in neonates with hyperbilirubinemia than in controls (RR = 1.50; 95% CI: 1.13–2.00). There were no significant differences in SLCO1B1 521 T > C between the hyperbilirubinemia and the control group (RR, 1.00; 95% CI, 0.72–1.40). No carriage of the C to A substitution at nucleotide 463 was detected.

Conclusion

The SLCO1B1 388 G > A variant is associated with neonatal hyperbilirubinemia in Chinese neonates.

Associations between the functional polymorphisms in the ABCB1 transporter gene and colorectal cancer risk: a case-control study in Turkish population

Colorectal cancer is among the most common cancer types in the world and its etiology involves the interaction of genetic and environmental factors. ABCB1 is highly expressed in the apical surface of colonic epithelial cells and acts as an efflux pump by transporting toxic endogenous substances, drugs and xenobiotics out of cells. ABCB1 polymorphisms may either change its protein expression or alter its function. Several studies have reported a possible association between ABCB1 variants and colorectal cancer, but no consistent conclusion has been arrived at. Therefore, we aimed to investigate the relationship between colorectal cancer and the functional common variants of ABCB1 (1236C > T; 2677G > T/A; 3435C > T). The distributions of the variants were determined in 103 patients with colorectal cancer and 150 healthy volunteers using polymerase chain reaction-restriction fragment length polymorphism methods. ABCB1 1236C > T was statistically significantly associated with colorectal cancer risk (OR, odd ratio = 1.91; 95% CI, confidence interval = 1.09-3.35; p = 0.034). In haplotype-based analysis, the proportion of individuals with the ABCB1 haplotype C1236-G2677-T3435 was significantly more common in patients than in controls (OR = 11.96; 95% CI = 2.59-55.32; p = 0.0004). We believe that the findings may be beneficial to the development of efficacious preventive strategies and therapies for colorectal cancer.

Influence of the functional polymorphisms in the organic anion transporting polypeptide 1B1 in the susceptibility to colorectal cancer

Colorectal cancer is an important cause of death throughout the world, and its etiology involves the interaction of genetic and environmental factors. Transporter proteins are important in protecting organs from xenobiotics or toxins. Organic anion-transporting polypeptide 1B1 (OATP1B1) plays role in hepatic uptake and clearance of albumin-bound amphipathic organic compounds, including endogen substances, drugs, or xenobiotics. The SLCO1B1 gene expressing OATP1B1 is highly polymorphic. Up to now, SLCO1BI variants were the focus of several investigations on drug pharmacokinetics and cancer susceptibility. However, no information has been available on association between SLCO1B1 and colorectal cancer risk. Therefore, the study aims to investigate the relationship between colorectal cancer and the functional common variants of SLCO1B1 (388 A>G, -11187 G>A, 521 T>C) and to estimate the prevalence of these variants in the Turkish population. To that end, the distributions of the variants were determined in 100 patients with colorectal cancer and 150 healthy volunteers. SLCO1B1 521 T>C was statistically significantly associated with colorectal cancer risk (odds ratio [OR]=2.66; 95% confidence interval [CI]=1.31-5.41; p=0.0057). In haplotype-based analysis, SLCO1B1 haplotype G(388)-T(11187)-T(521) might be associated with the development of colorectal cancer (OR=4.26; 95% CI=1.62-11.16; p=0.002). We believe that the findings may be beneficial to the development of efficacious preventive strategies and therapies for colorectal cancer.

Pharmacogenomic Diversity among Brazilians: Influence of Ancestry, Self-Reported Color, and Geographical Origin

BY VIRTUE OF BEING THE PRODUCT OF THE GENETIC ADMIXTURE OF THREE ANCESTRAL ROOTS: Europeans, Africans, and Amerindians, the present-day Brazilian population displays very high levels of genomic diversity, which have important pharmacogenetic/-genomic (PGx) implications. Recognition of this fact has prompted the creation of the Brazilian Pharmacogenomics Network (Refargen), a nationwide consortium of research groups, with the mission to provide leadership in PGx research and education in Brazil, with a population heath impact. Here, we present original data and review published results from a Refargen comprehensive study of the distribution of PGx polymorphisms in a representative cohort of the Brazilian people, comprising 1,034 healthy, unrelated adults, self-identified as white, brown, or black, according to the Color categories adopted by the Brazilian Census. Multinomial log-linear regression analysis was applied to infer the statistical association between allele, genotype, and haplotype distributions among Brazilians (response variables) and self-reported Color, geographical region, and biogeographical ancestry (explanatory variables), whereas Wright's F(ST) statistics was used to assess the extent of PGx divergence among different strata of the Brazilian population. Major PGx implications of these findings are: first, extrapolation of data from relatively well-defined ethnic groups is clearly not applicable to the majority of Brazilians; second, the frequency distribution of polymorphisms in several pharmacogenes of clinical relevance (e.g., ABCB1, CYP3A5, CYP2C9, VKORC) varies continuously among Brazilians and is not captured by race/Color self-identification; third, the intrinsic heterogeneity of the Brazilian population must be acknowledged in the design and interpretation of PGx studies in order to avoid spurious conclusions based on improper matching of study cohorts.

UGT1A1, SLCO1B1, and SLCO1B3 polymorphisms vs. neonatal hyperbilirubinemia: is there an association?

BACKGROUND

Jaundice is a physiological phenomenon; however, severe hyperbilirubinemia occurs in only 5 to 6% of the healthy newborn population. It has been suggested that genetic variation could enhance the risk of hyperbilirubinemia when coexpressed with other icterogenic conditions.

METHODS

The study included newborns with a gestational age of greater than 35 wk and weights greater than 2,000 g with indications for phototherapy. The polymorphisms from UGT1A1 (rs8175347), SLCO1B1 (rs4149056 and rs2306283), and SLCO1B3 (rs17680137 and rs2117032) were analyzed by capillary electrophoresis and hydrolysis probes.

RESULTS

A total of 167 hyperbilirubinemic infants and 247 control subjects were enrolled. The gender, ABO incompatibility, birth weight, and gestational age differed between the groups, but the allelic and genotypic frequency of the polymorphisms from SLCO1B genes did not. In logistic regression, the ABO incompatibility, gestational age, and polymorphic T allele of rs2117032 remained in the model. The presence of this polymorphism seemed to provide protection from hyperbilirubinemia. The individuals who were homozygous for the G allele of rs2306283 and who were glucose 6-phosphate-dehydrogenase deficient were more frequent among the cases.

CONCLUSION

Although genetic variation accounts for a good part of this condition, the association between different polymorphisms and environmental factors has yet to be explained.