This study aims to provide further insight into the phenotypic heterogeneity of Klinefelter syndrome (KS) by presenting clinical, hormonal, and genetic data from a large series of Egyptian infertile patients with KS. A retrospective case series of KS patients was studied over a period from January 2003 to April 2010. All patients underwent a complete history and physical examination; color duplex examination; semen analysis; measurement of total testosterone (T), follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), and prolactin (PRL); and chromosomal typing. Mosaic KS diagnosis was confirmed by fluorescence in situ hybridization. The series included 216 KS patients (198 nonmosaic, 16 mosaic, and 2 KS variants). Typical clinical signs of hypoandrogenism were observed in 86% of patients. Gynecomastia affected 20.8% of the patients. Eunuchoidal body proportions, with arm span exceeding height and lower segment length exceeding upper segment length, were detected in 43.9% and 64.4% of the patients, respectively. In all patients, a reduction in testicular size and azoospermia were detected. Normal levels of T, FSH, LH, E2, and PRL were detected in 44.5%, 3.7%, 3.3%, 93.5%, and 91.2% of patients, respectively. Differences were not significant between patients with classic KS and those with mosaic KS in terms of the frequency of clinical signs of hypoandrogenism, gynecomastia, low T concentrations, or high concentrations of FSH, LH, E2, and PRL (all P > .05). The results of the current study emphasize the heterogeneous clinical, hormonal, and genetic phenotype of infertile KS patients. Our findings support the usefulness of cytogenetic studies in infertile patients showing small testicular size and azoospermia, regardless of the presence of other clinical or endocrine findings.
