Idiopathic male infertility and androgen receptors.

In France, 12 to 15% of couples experience procreation difficulties. A diso rder of spermatogenesis (oligospermia, azoospermia), is responsible in 1/3 of cases. These forms of infertility, labelled idiopathic, probably have a genetic component, like microdeletions of the Y chromosome. The normal rate of circulating androgens suggests the implication, in some cases, of an ab normality from the receptor to the androgens (RA) of these male infertiliti es, whose number remains to be defined. Point mutations on exons of the gen e encoding the AR cannot account for all cases of infertility due to idiopa thic disorders of spermatogenesis. Expansion of the number of CAG triplets of exon 1 of the AR gene, already demonstrated in a fatal degenerative neur opathy (Kennedy's disease, in which more than 50% of patients are infertile ), has been detected in these cases of idiopathic infertility and would be responsible for AR dysfunction. The number of these triplets is also decrea sed in patients with androgen-dependent prostate cancer. The polymorphism, of repetition of CAG triplets would therefore be responsible for fine adjus tment of the AR between excessive and insufficient function. ICSI. (Intra-C ytoplasmic Sperm Injection) is currently proposed in these cases of inferti lity, but the consequences of transmission of these abnormalities to the of fspring are unknown.