FREQUENCY OF THE DELTA-CCR5 DELETION ALLELE IN THE URBAN BRAZILIAN POPULATION

Studies on screening genes conferring resistance to HIV-1 and AIDS ons et have shown a direct relationship between a 32 base pair (bp) deleti on in the CCR5 beta-chemokine receptor gene (Delta ccr5 mutant allele) and long survival of HIV-1 infected individuals bearing this mutation . These findings led to an interest in studies of Delta ccr5 allele di stribution in human populations. In the present study, polymerase chai n reactions (PCR) in genomic DNA samples, using specific CCR5 oligonuc leotide primers surrounding the breakpoint deletion, detected a 193-bp product from the normal CCR5 allele and a 161-bp product from the 32- bp deletion allele. In an investigation of the urban Brazilian populat ion we detected a 93% frequency of normal CCR5/CCR5 homozygous individ uals and a 7% frequency of CCR5/Delta ccv5 heterozygous individuals. T he frequency of the Delta ccr5 mutant allele in this population is 0.0 35; however, no homozygous Delta ccr5 individual has been detected thu s far. This is the first evidence for the contribution of the Delta cc r5 allele to the genetic background of the urban Brazilian population, which is characterized by intense ethnic admixture. These findings op en perspectives for further studies on the relationship between Delta ccr5 allele frequency and AIDS onset in high-risk HIV-1 exposures indi viduals. (C) 1998 Elsevier Science B.V. All rights reserved.