Based on pre-DNA racial/color methodology, clinical and pharmacological trials have traditionally considered the different geographical regions of Brazil as being very heterogeneous. We wished to ascertain how such diversity of regional color categories correlated with ancestry. Using a panel of 40 validated ancestry-informative insertion-deletion DNA polymorphisms we estimated individually the European, African and Amerindian ancestry components of 934 self-categorized White, Brown or Black Brazilians from the four most populous regions of the Country. We unraveled great ancestral diversity between and within the different regions. Especially, color categories in the northern part of Brazil diverged significantly in their ancestry proportions from their counterparts in the southern part of the Country, indicating that diverse regional semantics were being used in the self-classification as White, Brown or Black. To circumvent these regional subjective differences in color perception, we estimated the general ancestry proportions of each of the four regions in a form independent of color considerations. For that, we multiplied the proportions of a given ancestry in a given color category by the official census information about the proportion of that color category in the specific region, to arrive at a “total ancestry” estimate. Once such a calculation was performed, there emerged a much higher level of uniformity than previously expected. In all regions studied, the European ancestry was predominant, with proportions ranging from 60.6% in the Northeast to 77.7% in the South. We propose that the immigration of six million Europeans to Brazil in the 19^th and 20^th centuries - a phenomenon described and intended as the “whitening of Brazil” - is in large part responsible for dissipating previous ancestry dissimilarities that reflected region-specific population histories. These findings, of both clinical and sociological importance for Brazil, should also be relevant to other countries with ancestrally admixed populations.

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.

Background: Malaria is among the most prevalent parasitic diseases worldwide. In Brazil, malaria is concentrated in the northern region, where Plasmodium vivax accounts for 85% disease incidence. The role of genetic factors in host immune system conferring resistance/susceptibility against P. vivax infections is still poorly understood. Methods: The present study investigates the influence of polymorphisms in 18 genes related to the immune system in patients with malaria caused by P. vivax. A total of 263 healthy individuals (control group) and 216 individuals infected by P. vivax (malaria group) were genotyped for 33 single nucleotide polymorphisms (SNPs) in IL1B, IL2, IL4, IL4R, IL6, IL8, IL10, IL12A, IL12B, IL12RB1, SP110, TNF, TNFRSF1A, IFNG, IFNGR1, VDR, PTPN22 and P2X7 genes. All subjects were genotyped with 48 ancestry informative insertion-deletion polymorphisms to determine the proportion of African, European and Amerindian ancestry. Only 13 SNPs in 10 genes with differences lower than 20% between cases and controls in a Poisson Regression model with age as covariate were further investigated with a structured population association test. Results: The IL1B gene -5839C > T and IL4R 1902A > G polymorphisms and IL12RB1 -1094A/-641C and TNF -1031 T/-863A/-857 T/-308 G/-238 G haplotypes were associated with malaria susceptibility after population structure correction (p = 0.04, p = 0.02, p = 0.01 and p = 0.01, respectively). Conclusion: Plasmodium vivax malaria pathophysiology is still poorly understood. The present findings reinforce and increase our understanding about the role of the immune system in malaria susceptibility.

Background: Chloroquine/primaquine is the current therapy to eliminate Plasmodium vivax infection in the Amazon region. Aims: This study investigates CYP1A2, CYP2C8, CYP2C9, CYP3A4 and CYP3A5 genet...

Variants in uptake and efflux transporters can influence diverse statin pharmacokinetics in different populations. This study aimed to investigate the influence of SLCO1B1 gene polymorphism on simvastatin treatment efficacy in a Brazilian population of European ancestry. Two hundred and sixteen hypercholesterolemic patients were treated with 20 mg/day simvastatin for 6 months. Plasma lipid and lipoprotein levels were measured at baseline and after 2 and 6 months of treatment. The single nucleotide polymorphisms (SNPs) c.388A>G, c.463C>A and c.521T>C at SLCO1B1 gene were determined by allelic discrimination with TaqMan 5'-nuclease assays. The 388G allele was observed in 160 patients, the 521 C allele was observed in 64 individuals, whereas 61 subjects were 463 A allele carriers. Carriers of the SLCO1B1 388G allele had a greater reduction of total cholesterol and LDL cholesterol with simvastatin treatment, when compared with 56 388A homozygotes (-28.8% vs. -15.8%, p=0.005 and -39.0% vs. -30.6%, p=0.003; respectively). The c.463C>A and c.521T>C SNPs were not associated with simvastatin treatment. The SLCO1B1 haplotypes showed no statistically significant differences in mean percentage reductions in lipid and lipoprotein levels after simvastatin treatment. The present study suggests that the SLCO1B1 c.388A>G polymorphism could play a role in the inter-individual variation of clinical response to simvastatin in Brazilians. These results add to those that suggest that the effects of SLCO1B1 variants may be statin specific.