Population analysis of xenobiotic metabolizing genes in South Brazilian Euro and Afro-descendants

ABSTRACT

Individual variability in xenobiotic metabolism has been associated with susceptibility to developing complex diseases. Genes involved in xenobiotic metabolism have been evaluated in association studies; the difficulty of obtaining accurate gene frequencies in mixed populations makes interpretation of the results difficult. We sought to estimate population parameters for the cytochrome P450 and glutathione S-transferase gene families, thus contributing to studies using these genes as markers. We describe the frequencies of six genes (CYP1A1, CYP2D6, CYP2E1, GSTM1, GSTT1, and GSTP1) and estimate population parameters in 115 Euro-descendants and 196 Afro-descendants from Curitiba, South of Brazil. PCR-based methods were used for genotyping, and statistical analysis were performed by AMOVA with ARLEQUIN software. The mutant allele frequencies in the Afro-descendants and Euro-descendants, respectively, were CYP1A1*2A = 30.1 percent and 15.2 percent; CYP2D6*4 = 14.5 percent and 21.5 percent; CYP2E1*5B = 7.9 percent and 5 percent; GSTP1*B = 37.8 percent and 28.3 percent. The null genotype frequencies were GSTM1*0 = 36.8 percent and 46.1 percent; GSTT1*0 = 24.2 percent and 17.4 percent.