Azoospermia associated with a mutation in the ligand-binding domain of an androgen receptor displaying normal ligand binding, but defective trans-activation.
Results suggest that an increase in the number of CAG repeats in the androgen receptor gene to 31 or greater may be associated with the etiology of at least some cases of idiopathic azoospermia.
Androgen receptor (AR) gene mutations have been shown to cause androgen insensitivity syndrome with altered sexual differentiation in XY individuals, ranging from a partial insensitivity with male phenotype and azoospermia to a complete insensitivity with female phenotype and the absence of pubic and axillary sexual hair after puberty.
To assess the contribution of these genetic defects to male infertility, 61 Israeli men with severe oligo- (n = 15) or azoospermia (n = 46), were screened for Y chromosome microdeletions, and the AR-(CAG)n repeat length.
Previous studies have shown that total AR knockout would lead to incomplete spermatogenesis and lowered serum testosterone levels in mice, resulting in azoospermia and infertility.
The results of this study confirm the importance of the AZF region in normal spermatogenesis, whereas it shows no link between the length of CAG repeats in the AR gene and male azoospermia in Jordanian group examined.