Incidental deviation of short and long CAG repeats in the androgen receptor gene for Japanese male infertility

Aim: The present study investigated whether the CAG repeat length in exon 1 of the androgen receptor gene on the X chromosome is associated with male infertility. Methods: The CAG repeat length between the two groups of 143 idiopathic infertile Japanese men with severe oligozoospermia or non‐obstructive azoospermia and 100 fertile men were analyzed. The azoospermia factor deletions were also analyzed. Results: Although there was no significant difference in the mean length between the two groups observed (P = 0.055), the distribution in the infertile men was wider than that in the fertile men. Similar results were detected in the combined data from previous Japanese reports and our present data including 261 infertile and 235 fertile men. We detected 12 and 34 CAG repeats in the present study that were the shortest and the longest repeats in Japan, respectively. Conclusions: These results suggest that excessive expansion or reduction of CAG repeats might be related to impaired spermatogenesis. (Reprod Med Biol 2003; 2: 145–150)