Several variations in immune system-related genes have been linked to AIDS acquisition and disease progression. Two protective SNPs are in the CCR5 gene:
- rs333 (delta32)
Compared to individuals without the Delta32 mutation in CCR5, individuals with one or two copies of the rs1799864(A) allele in the CCR2 gene have 58% lower risk of developing AIDS during the first 4 years after testing positive for HIV, 19% lower risk during the subsequent 4 years, and no significant protection thereafter. [PMID 12556692] No protective effect (i.e., no benefit) was seen for this SNP once AIDS had developed. [PMID 11694103]
For further details about this study, see .