CCR5-32 Delta is exciting. It presents possibilities for new ways to protect against HIV. Many wonder if genetic testing is available yet to see if one has the mutation. There are some tests available (just google CCR5-32 Delta testing and you’ll see) but it is not yet widespread or widely recommended. The mutation is not completely fool proof. Cases of homozygous carriers that have become infected with HIV have been reported. These few exceptions have dissuaded health officials from fully supporting genetic tests over ethical concerns. It would not be wise for those with the mutation to assume that they can lead a dangerous lifestyle and remain healthy. Understanding how and why certain people are resistant to HIV/AIDS with the help of CCR5-32 Delta will hopefully lead to new and highly successful treatments in our lifetime.
The delta 32 gene mutation is a deletion of part of the genetic sequence making up the CCR5 receptor which is found on the surface of the CD4 cell. HIV uses this receptor to connect with and infect a CD4 cell.
We all have two genes for each characteristic (two sets of chromosomes), one from the mother and one from the father. Having one mutated gene for delta 32 and one regular gene (called heterozygous) is related to a reduced risk from HIV compared to someone with two regular genes. This type of heterozygous mutation occurs in about 20% of Caucasians but in about 1% of people from African origin.
If both genes carry the delta 32 mutation this is called homozygous and occurs in only about 1% of causations. This provides a much stronger protection against HIV. However, this protection is only against a type of HIV that uses the CCR5 co-receptor (called R5 tropic).
Approximately 10% of infections are related to a type of HIV that uses CXCR4 (called X4 tropic) and the delta 32 mutation provide no protection here. The chance someone has X4 tropic HIV increase with the time they have been HIV positive.
Therefore people who are homozygous for delta 32 can still become infected with HIV.