Association of the androgen receptor CAG repeat polymorphism with Alzheimer's disease in men.

We examined the CAG repeat polymorphism in exon 1 of the androgen receptor (AR) in an Oxford cohort of 150 cases (101 men) of definite or probable Alzheimer's disease (AD) and 190 elderly controls (140 men). We found that short alleles (< or = 20 CAG repeats) were associated with AD (adjusted odds ratio = 2.5, 95% confidence intervals: 1.2-5.0) in men, but not in women. This association appeared stronger in early-onset AD (< 65 years). We conclude that this AR polymorphism is of potential relevance to the risk of AD in men.