Variation in human β‐defensin genes: new insights from a multi‐population study. (29th November 2012) - Mehlotra, R. K.
Summary Human β‐defensin 2 (hBD‐2) and hBD‐3, encoded by DEFB4 and DEFB103A, respectively, have shown anti‐HIV activity, and both genes exhibit copy number variation (CNV). Although the role of hBD‐1, encoded by DEFB1, in HIV‐1 infection is less clear, single nucleotide polymorphisms (SNPs) in DEFB1 may influence viral loads and disease progression. We examined the distribution of DEFB1 SNPs and DEFB4/103A CNV, and the relationship between DEFB1 SNPs and DEFB4/103A CNV using samples from two HIV/AIDS cohorts from the United States (n = 150) and five diverse populations from the Coriell Cell Repositories (n = 46). We determined the frequencies of 10 SNPs in DEFB1 using a post‐PCR, oligonucleotide ligation detection reaction–fluorescent microsphere assay, and CNV in DEFB4/103A by real‐time quantitative PCR. There were noticeable differences in the frequencies of DEFB1 SNP alleles and haplotypes among various racial/ethnic groups. The DEFB4/103A copy numbers varied from 2 to 8 (median, 4), and there was a significant difference between the copy numbers of self‐identified whites and blacks in the US cohorts (Mann–Whitney U‐test P = 0.04). A significant difference was observed in the distribution of DEFB4/103A CNV among DEFB1 ‐52G/A and ‐390T/A genotypes (Kruskal–Wallis P = 0.017 and 0.026, respectively), while not in the distribution of DEFB4/103A CNV among ‐52G/A_‐44C/G_‐20G/A diplotypes. These observations provide additional insights for further investigating the complex interplay between β‐defensin genetic polymorphisms and susceptibility to, or the progression or severity of, HIV infection/disease.