Distribution of the mutated delta32 allele of the CCR5 gene in a Sicilian population

The CCR5 gene encodes a cell-surface chemokine receptor molecule that serves as a co-receptor for macrophagetropic strains of human immunodeficiency virus type 1 (HIV-1). A mutation in this gene may alter the expression or the function of the protein product, thereby altering chemokine binding and/or signalling or HIV-1 infection of cells that normally express CCR5 protein. Individuals homozygous for a 32-bp deletion allele of CCR5 (CCR5 Δ32), heritable as a Mendelian trait, are relatively resistant to HIV-1 infection. The CCR5 Δ32 mutation is present in the Caucasian population at different frequencies. The aim of this study was to investigate the frequency of truncated alleles of the CCR5 Δ32 gene in a Sicilian population, as the interpopulation variation in CCR5 Δ32 frequency may be a significant factor in the prediction of AIDS endemicity in future studies. We examined 901 healthy individuals from several Sicilian provinces. We found a mean (± standard deviation) Δ32 allele frequency (fr) of 0.04 ± 0.012. The highest value was observed in the province of Messina, with a mean Δ32 allele frequency of 0.06 ± 0.024, where we collected samples from a cohort of 114 HIV-1-infected individuals. The observed frequency amongst these patients was quite low (fr = 0.03 ± 0.031) compared to the healthy population, although the difference was not statistically significant.