USP9Y and Sertoli Cell-Only Syndrome: The prevalence of AZF microdeletions in infertile men ranges from 12% to 61.33%,[8] while deletions in the AZFa region represent only 0.1% to 3.8% of the Yq microdeletions.[9,10] The AZFa microdeletions are associated with male infertility and spermatogenic failure.[11] Complete deletions in the AZFa region result in azoospermia and Sertoli cell-only syndrome.[12] However, cases of partial AZFa deletions are rare and poorly understood.