Genetic Variability of the Human SRD5A2 Gene: Implications for Prostate Cancer Risk1

Klevated dihydrotestosterone levels have been suggested to increase the risk of prostate cancer. The human SRD5A2 gene encodes the type II steroid 5a-reductase, which converts testosterone to the more bioactive compound dihydrotestosterone. We have determined the distribution of a dinucleotide repeat in low-risk Asian-Americans, high-risk African-Amer icans, and intermediate-risk non-Hispanic Whites. We found this marker to be more polymorphic than previously reported, with some alÃ-elesbeing specific to African-Americans. Genetic variants of the SRD5A2 gene may play a role in predisposition to prostate cancer and in explaining the substantial racial/ethnic variability in risk.