A decade of experience emphasizes that testing for Y microdeletions is essential in American men with azoospermia and severe oligozoospermia.

OBJECTIVE: To evaluate the benefit of Y microdeletion testing.
DESIGN: Retrospective analysis.
SETTING: University-based male fertility clinic and genetics laboratory. PATIENT(S): A total of 1,591 men with sperm concentrations less than 5 million sperm/mL. INTERVENTION(S): Semen analysis, Y microdeletion testing, microdissection testicular sperm extraction (TESE). MAIN OUTCOME MEASURE(S): Sperm concentration, incidence and nature of Y microdeletions, microdissection TESE outcome. RESULT(S): We identified 149 microdeletions (9.4%). 10.4% of azoospermic men and 10.1% of men with sperm concentrations >0-1 million sperm/mL harbored microdeletions. Two-thirds of microdeletions in azoospermic men were AZFa, AZFb, AZFb+c, or complete Yq deletions. Virtually all microdeletions in oligozoospermic patients were AZFc deletions. Seven hundred eighteen patients underwent microdissection TESE, including 41 with microdeletions. Microdissection TESE failed in all patients with AZFa, AZFb, AZFb+c, and complete Yq deletions. Sperm were retrieved in 15/21 AZFc deleted patients (71.4%). The presence of an AZFc deletion was associated with increased likelihood of sperm retrieval when compared with the 48.8% retrieval rate in 385 idiopathically azoospermic men who consecutively underwent microdissection TESE at our institution during the study period. Clinical pregnancy was achieved in 10/15 azoospermic AZFc deleted patients for whom sperm were successfully retrieved. CONCLUSION(S): Of azoospermic and severely oligozoospermic American men, 10% harbor Y microdeletions that alter prognosis for surgical sperm retrieval and are vertically transmissible. Y microdeletion testing is essential for genetic and preoperative counseling in these patients.