Duffy blood group gene polymorphisms among malaria vivax patients in four areas of the Brazilian Amazon region

<p>Abstract</p> <p>Background</p> <p>Duffy blood group polymorphisms are important in areas where <it>Plasmodium vivax </it>predominates, because this molecule acts as a receptor for this protozoan. In the present study, Duffy blood group genotyping in <it>P. vivax </it>malaria patients from four different Brazilian endemic areas is reported, exploring significant associations between blood group variants and susceptibility or resistance to malaria.</p> <p>Methods</p> <p>The <it>P. vivax </it>identification was determined by non-genotypic and genotypic screening tests. The Duffy blood group was genotyped by PCR/RFLP in 330 blood donors and 312 malaria patients from four Brazilian Amazon areas. In order to assess the variables significance and to obtain independence among the proportions, the Fisher's exact test was used.</p> <p>Results</p> <p>The data show a high frequency of the <it>FYA/FYB </it>genotype, followed by <it>FYB/FYB, FYA/FYA</it>, <it>FYA/FYB-33 </it>and <it>FYB/FYB-33</it>. Low frequencies were detected for the <it>FYA/FY</it>^<it>X</it>, <it>FYB/FY</it>^<it>X</it>, <it>FYX/FY</it>^{<it>X </it>}and <it>FYB-33/FYB-33 </it>genotypes. Negative Duffy genotype (<it>FYB-33/FYB-33</it>) was found in both groups: individuals infected and non-infected (blood donors). No individual carried the <it>FY</it>^<it>X</it><it>/FYB-33 </it>genotype. Some of the Duffy genotypes frequencies showed significant differences between donors and malaria patients.</p> <p>Conclusion</p> <p>The obtained data suggest that individuals with the <it>FYA/FYB </it>genotype have higher susceptibility to malaria. The presence of the <it>FYB-33 </it>allele may be a selective advantage in the population, reducing the rate of infection by <it>P. vivax </it>in this region. Additional efforts may contribute to better elucidate the physiopathologic differences in this parasite/host relationship in regions endemic for <it>P. vivax </it>malaria, in particular the Brazilian Amazon region.</p

CYP1A1, GSTM1, GSTT1 and GSTP1 polymorphisms in an Afro-Brazilian group

Gene polymorphisms involved in the metabolism of drugs and chemical carcinogens seem to be responsible for differences in the susceptibility of individuals to cancer, but genetic population studies are needed to characterize these polymorphisms in different ethnic populations. We investigated polymorphisms of the cytochrome P450 (CYP) gene CYP1A1 and the glutathione S-transferase (GSTs) genes GSTM1, GSTT1 and GSTP1 in a sample of Afro-Brazilians from the southern Brazilian city of Porto Alegre to verify if there were ethnic differences compared to the polymorphisms of the same genes in a previously described sample of Brazilians of European descent from the same city. The allele frequencies detected in the Afro-Brazilian population investigated in this study were CYP1A1*2A (30%) and GSTP1*Val (42%) while the frequency of the GSTM1 null genotype was 34% and that of the GSTT1 null genotype was 28%. Significant differences in genotype distribution and allelic frequencies were detected between Brazilians of African and of European descent from Porto Alegre in terms of the polymorphisms CYP1A1*2A (p = 0.003), GSTP1-Ile105Val (p = 0.002) and the GSTM1 null genotype (p = 0.01) but there was no detectable significant difference in respect to GSTT1 null genotype frequencies