Screening for AZF deletion in a large series of severely impaired spermatogenesis patients

Recent investigations have pointed to a high prevalence of Y chromosome sub microscopic deletions in men with severely impaired spermatogenesis. We rep ort on the incidence in 128 infertile men, in whom karyotype, sperm count, and hormonal parameters were evaluated. Patients with abnormal karyotype (o ther than an abnormal Y chromosome) or sperm concentration of more than 2 m illion/mL were excluded. Genomic DNA was extracted from the peripheral leuk ocytes of 57 men with azoospermia and 71 with severe oligospermia. Molecula r analysis was performed by 3 multiplex polymerase chain reactions using a set of 9 sequence tagged sites (STSs) from 3 different regions of the Y chr omosome: AZFa, AZFb, and AZFc. In 7% of the studied patients Yq microdeleti ons were detected, with a high prevalence in men with azoospermia (14%). No deletions were detected in the AZFa region. Deletions were present in AZFb , AZFc, or both regions. The deletion observed in 1 patient that did not ov erlap with the DAZ region demonstrates that genes other than DAZ may also b e involved in the pathogenesis of some subsets of male infertility. Further more, common Yq deletions present different testicular pictures, suggesting that some unknown factors may be disturbing spermatogenesis. Because men w ith severe infertility suffer a high risk of Y chromosome deletion, screeni ng for these men is recommended prior to treatment with assisted reproducti on.