CAG repeat length analysis and mutation screening of the androgen receptorgene in Japanese men with idiopathic azoospermia

Because androgens are required for normal spermatogenesis, we are investiga ting abnormalities in the androgen receptor as a possible cause of impaired spermatogenesis in patients with idiopathic male infertility. The CAG repe at length in exon 1 and mutations of the androgen receptor gene were studie d in 30 men with idiopathic azoospermia and in 51 fertile men. In men with azoospermia, plasma luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone levels were measured and testicular biopsies were p erformed. The CAG repeat length ranged from 19 to 30 (mean 23.4 +/-2.9) and from 17 to 28 (mean 23.7 +/-3.2) in men with azoospermia and in controls, respectively. There was no significant difference between the 2 groups. In men with azoospermia, the Johnsen testicular biopsy score negatively correl ated with plasma FSH (P<.01). However, the Johnsen testicular biopsy score did not correlate with plasma LH and testosterone levels. The CAG repeat le ngth did not correlate with the Johnsen testicular biopsy score, or with pl asma concentrations of LH, FSH, and testosterone. No abnormalities in the a ndrogen receptor gene were detected. These facts suggest that the CAG repea t length and alterations in the androgen receptor gene are not associated w ith the etiology of idiopathic azoospermia.