Multicenter study of genetic abnormalities associated with severe oligospermia and non-obstructive azoospermia

OBJECTIVE: Genetic defects are identified in nearly 20% of infertile males. Determining the frequency and types of major genetic abnormalities in severe male infertility helps inform appropriate genetic counseling before assisted reproductive techniques. METHODS: Cytogenetic results of 912 patients with non-obstructive azoospermia (NOA) and severe oligozoospermia (SOS) in Eastern China were reviewed in this multicenter study from January 2011 to December 2015. Controls were 215 normozoospermic men with offspring. RESULTS: Among all patients, 22.6% (206/912) had genetic abnormalities, including 27.3% (146/534) of NOA patients and 15.9% (60/378) of SOS patients. Chromosomal abnormalities (all autosomal) were detected in only 1.9% (4 /215) of controls. In NOA patients, sex chromosomal abnormalities were identified in 25.8% (138/534), of which 8% (43/534) had a 47,XXY karyotype or its mosaic; higher than the SOS group prevalence (1.1%; 4/378). The incidence of Y chromosome microdeletions was lower in the SOS group (13.2%; 50/378) than in the NOA group (17.8%; 95/534). CONCLUSIONS: The high prevalence of genetic abnormalities in our study indicates the importance of routine genetic testing in severe male infertility diagnosis. This may help determine the choice of assisted reproductive technique and allow specific pre-implantation genetic testing to minimize the risk of transmitting genetic defects.