[Idiopathic male infertility and androgen receptors]

In France, 12 to 15% of couples experience procreation difficulties. A disorder 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 abnormality from the receptor to the androgens (RA) of these male infertilities, whose number remains to be defined. Point mutations on exons of the gene encoding the AR cannot account for all cases of infertility due to idiopathic disorders of spermatogenesis. Expansion of the number of CAG triplets of exon 1 of the AR gene, already demonstrated in a fatal degenerative neuropathy (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 decreased in patients with androgen-dependent prostate cancer. The polymorphism of repetition of CAG triplets would therefore be responsible for fine adjustment of the AR between excessive and insufficient function. ICSI. (Intra-Cytoplasmic Sperm Injection) is currently proposed in these cases of infertility, but the consequences of transmission of these abnormalities to the offspring are unknown.