Is increased CAG repeat length in the androgen receptor gene a risk factor for male subfertility?

PURPOSE: Increased length of the CAG repeat in the androgen receptor gene may be related to male subfertility. Expansion to 38-62 CAG repeats leads to the neurodegenerative disorder with male infertility called Kennedy's disease. Recently it was suggested that slight expansion is related to male subfertility. In this study we investigated the association of male subfertility with the length of CAG repeats in the androgen receptor.

MATERIALS AND METHODS: CAG repeat length in the androgen receptor gene was investigated in 75 subfertile men, who were mainly candidates for intracytoplasmic sperm injection. Sperm parameters varied from azoospermia to severe oligoasthenoteratozoospermia. The control group consisted of 70 men who predominantly had bladder cancer. DNA was isolated from peripheral blood and genotyping was performed with polymerase chain reaction based methods.

RESULTS: No statistically significant difference in the mean length of the CAG repeat plus or minus standard deviation was noted in subfertile men and controls (22.2 +/- 3.1 and 21.7 +/- 3.4, respectively). The length of the CAG repeat in the androgen receptor was not related to the degree of impaired spermatogenesis or clinical characteristics of the subfertile men.

CONCLUSIONS: Increased length of CAG repeats in the androgen receptor gene is not a risk factor for male subfertility.