ABSTRACT
<p><b>OBJECTIVE</b>To study the incidence of the chromosome abnormalities and Y chromosome microdeletions in Chinese patients with azoospermia and cryptozoospermia.</p><p><b>METHODS</b>Conventional chromosomal karyotyping was used to analyze the chromosome abnormalities. Genomic DNA was extracted from peripheral blood samples and multiplex polymerase chain reactions (PCR) analyses were performed using specific primers to confirm the presence or absence of Y chromosome microdeletions. A total of 997 patients with azoospermia and cryptozoospermia were enrolled in the study.</p><p><b>RESULTS</b>The incidence of chromosome abnormalities in the patient with azoospermia and cryptozoospermia was 28.4%. The major abnormal karyotypes included 47,XXY, 46,XY (Y>G), 46,XX, chimera and translocations. The incidence of the Y chromosome microdeletions was 17.4%. They were mainly found in the karyotypes of 46,XY and 46,XY (Y>G).</p><p><b>CONCLUSION</b>Chromosome abnormalities were the most common hereditary causes of the patients with azoospermia and cryptozoospermia. The incidence of Y chromosome microdeletion was higher in the patients with karyotype of 46,XY and 46,XY (Y>G). Therefore, detection of the AZF microdeletion in these patients is helpful to determine the etiology and avoid the unnecessary treatment and vertical transmission of the genetic defects.</p>