To investigate the clinical, hormonal, and genetic factors in infertile men with idiopathic nonobstructive azoospermia (NOA) or azoospermic Klinefelter syndrome (KFS), a total of 556 and 96 patients, respectively, were included in this study. All patient samples were analyzed cytogenetically. Serum reproductive hormone levels were measured. Microdeletions in the azoospermia factor (AZF) region of the Y chromosome were detected by multiplex PCR using 16 specific sequence-tagged sites. FSH and LH levels in both NOA and KFS patients were significantly higher than the normal range, and the testosterone level in KFS patients was significantly lower. Ninety-two (95.8%) of the KFS patients showed non-mosaic 47,XXY karyotypes and 47,XXY,inv(9)(p11.1q13); the other KFS patients had mosaic karyotypes of 47,XXY/46,XY, 47,XXY/46,XX, and 47,XXY/48,XXXY/46,XX. Among the 556 idiopathic NOA patients with normal karyotypes, 67 (12.05%) had microdeletions in the AZF region of the Y chromosome. Microdeletions were most frequently detected in the AZFc region, followed by AZFa, AZFb, AZFbc, and partial AZFc deletions. However, Y chromosome microdeletions were not found in any of the azoospermic KFS patients. In view of the hormonal and genetic abnormalities in infertile men with idiopathic NOA and with azoospermic KFS, genetic testing for karyotype, Y chromosome microdeletions, and hormonal parameters is advocated.
