An interethnic comparison of the distribution of vitamin D receptor genotypes and haplotypes

Background: The biological actions of vitamin D receptor (VDR) may be affected by genetic variations in the VDR gene. While there are interethnic differences in the frequency of VDR gene variants, there is little haplotype information, especially from admixed populations. We examined the distribution of genetic variants of 3 VDR polymorphisms (BsmI, ApaI and FokI) and haplotypes in black and white Brazilians. We have also compared our results with those from the HapMap project. Methods: We studied 120 subjects self-reported as black, and 100 subjects self-reported as white (total N=220; men and women; age range: 1956 years). Genomic DNA was extracted from venous blood and the genotypes for the VDR gene polymorphisms were determined by PCR followed by restriction fragment length digestion and gel electrophoresis. Haplotypes were inferred with the program PHASE ver. 2.1. Results: While the distribution of VDR genotypes or alleles for the 3 VDR gene polymorphisms in Brazilians showed no interethnic differences (all P<0.05), significant differences were found for the ApaI and FokI polymorphisms in the HapMap populations (both P<0.05). While no interethnic differences in the distribution of haplotypes were found in Brazilians (P>0.05), significant differences were found in the HapMap populations (P<0.05). Conclusions: VDR genotype and haplotype differences between the Brazilian population and the HapMap population gives support to the idea that significant differences in haplotype structures may exist between different populations, especially admixed populations. (c) 2007 Elsevier B.V. All rights reserved.