[Search for microdeletions in the long arm of chromosome Y in 48 infertile men].

About 30% of infertilities are from male origin. They appear in some cases de novo and considered idiopathic. The aim of our work is to evaluate, in these cases, the Y chromosome long arm microdeletion prevalence within the AZF a, b and c regions by molecular biology technics. Were excluded from our study, azoo-oligospermia from hereditary, endocrine, obstructive origins or with a constitutional cytogenetic abnormality. 48 infertile men with a spermogram-proven azoo-oligospermia were studied. Among them, 30 were idiopathics, 8 out of them exhibited a genital infection past history or biological abnormalities suggesting partial obtruction of the genito-urinary tractus. 8 cases of varicocela and 10 of cryptorchidia were also studied. Peripheral blood DNA was extracted from each patient, then amplified by multiplex PCR with STS genomic markers from the 3 Y chromosome AZF zones. PCR products were then analysed on agarose gels. Considering the difficulty to affirm the absence of a signal in molecular biology, each suspicion of deletion was checked by multiplex PCR complication with the SRY marker. 5 Y chromosome long arm microdeletions were diagnosed among our 48 patients. All of them included the AZFc zone and the intragenic DAZ gene markers. Moreover a larger Y chromosome deletion encompassing the 3 AZF zones was diagnosed, and confirmed by the cytogenetic analysis. All the Y chromosome microdeletions were observed in the 22 truly idiopathic azoo/oligospermia, corresponding to a proportion of 22.7% which falls to 10.4% considering the whole population of 48 studied people (closer to the published data). The relatively high proportion of microdeletions found in our series, underlines the need of a strict patient selection to avoid unnecessary search for long arm Y chromosome microdeletions.