Phenotypic differences in mosaic Klinefelter patients as compared with non-mosaic Klinefelter patients

Objective: To determine whether men with Klinefelter syndrome (KS) have the same phenotype as men with mosaic KS. Design: Subject identification via prospectively collected database. Setting: Male infertility specialty clinic. Patient(s): Men undergoing a fertility evaluation from 2005 to 2012 at a single male infertility specialty clinic and having a karyotype demonstrating KS (mosaic or non-mosaic). Intervention(s): None. Main Outcome Measure(s): Testicular size, and semen and hormone parameters, genetic evaluation, and signs of testosterone (T) deficiency using validated questionnaires. Result(s): Of 86 men identified with KS, 6 (6.7%) were mosaic KS, and 80 (93.3%) were non-mosaic KS. Men with mosaic KS had lower baseline luteinizing hormone (LH) levels (10.31 IU/L +/- 5.52 vs. 19.89 IU/L +/- 6.93), lower estradiol levels (58.71 +/- 31.10 pmol/L vs. 108.57 +/- 43.45 pmol/L), larger mean testicular volumes (11 +/- 7.3 mL vs. 6.35 +/- 3.69 mL), and a higher mean total sperm count (4.43 +/- 9.86 M/mL vs. 0.18 +/- 1.17 M/mL). A higher proportion of men with mosaic KS had sperm in the ejaculate: 3 (50%) of 6 versus 3 (3.75%) of 80. The Sexual Health Inventory for Men (SHIM) and Androgen Deficiency in the Aging Male (ADAM) questionnaire scores were not different between groups. Conclusion(s): Men with mosaic KS seem to be more well androgenized than their non-mosaic KS counterparts, both with respect to hormones and sperm in the ejaculate. (C) 2014 by American Society for Reproductive Medicine.