Screening for microdeletions in human Y chromosome--AZF candidate genes and male infertility.

About 30% of couple infertilities are of male origin, some of them caused by genetic abnormalities of the Y chromosome. Deletions in AZF region can cause severe spermatogenic defects ranging from non-obstructive azoospermia to oligospermia. The intracytoplasmatic sperm injection technique (ICSI) is rapidly becoming a versatile procedure for human assisted reproduction in case of male infertility. The use of ICSI allows Y chromosome defects to be passed from father. The goal of our study is to evaluate the frequency of microdeletions in the long arm of Y chromosome, within the AZF regions, in these cases of infertilities, using molecular genetics techniques. Thirty infertile men with azoospermia or oligozoospermia, determined by spermogram, were studied after exclusion of patients with endocrine or obstructive causes of infertility. Peripheral blood DNA was extracted from each patient, then amplified by multiplex PCR with STS genomic markers from the Y chromosome AZF zones. Each case was checked by multiplex PCR through coamplification with the SRY marker. Three men with microdeletions of the long arm of the Y chromosome were diagnosed among the 30 patients, corresponding to a proportion of 10%. The relatively high proportion of microdeletions found in our population suggest the need for strict patient selection to avoid unnecessary screening for long arm Y chromosome microdeletions. The molecular diagnostics was performed according to the current European Academy of Andrology laboratory guidelines for molecular diagnosis of Y chromosomal microdeletions.