In the news

The HIV virus makes use of a human cell-surface receptor protein known as CCR5 to help it enter cells. Within the last few years it has been found that some genetic variants of CCR5 are associated with slower progression from HIV infection to AIDS. A recent study now adds to this picture by showing that there is also at least one variant of CCR5 that is associated with more rapid progression of the disease. 12.7% of Caucasians and 6.7% of African Americans are homozygous for this variant, which has a characteristic sequence in a region that regulates expression of the gene.

Comment: This is the first report of a common allelic variant associated with acceleration of AIDS progression. The authors emphasise that genetic susceptibility to AIDS is probably determined by several different human genes that function in the immune system. The rapid progress in this field may make it a useful model for other diseases whose onset or course is affected by a combination of genetic susceptibility and environmental influences.