Mutation screening and CAG repeat length analysis of the androgen receptor gene in Klinefelter's syndrome patients with and without spermatogenesis.

BACKGROUND Mutations of the androgen receptor (AR) gene give rise to a wide array of phenotypic abnormalities. A systematic analysis of the AR gene in patients with 47,XXY has not previously been performed. METHODS Mutations of the AR gene and expansion of the CAG repeats in exon 1 of the AR gene were studied in 13 patients with Klinefelter's syndrome either with (n = 1) or without (n = 12) spermatogenesis. RESULTS No abnormalities in the AR gene were detected by single strand conformational polymorphism analysis. The CAG lengths ranged from 17 to 27 (mean +/- SD 22.8 +/- 3.3, median 23) for Klinefelter patients or from 17 to 28 (mean +/- SD 23.2 +/- 2.6, median 23) for control subjects. X-inactivation analysis for the methylation status of the AR gene was performed in seven patients who were heterozygous for CAG repeats of different length, showing that the longer CAG repeat alleles underwent random but more frequent inactivation in five patients and skewed inactivation in two. CONCLUSIONS An AR gene abnormality does not constitute an important factor for impaired spermatogenesis in patients with Klinefelter's syndrome.