LAUSR

PURPOSE OF REVIEW The review presents a clinical algorithm for the evaluation and treatment for adolescents with Klinefelter's syndrome who desire fertility preservation. RECENT FINDINGS Sperm is present in the ejaculate in around 8% of men with Klinefelter's syndrome. Although most are severely oligospermic/azoospermic, 43-45% of men will have sperm found during a testicular sperm extraction, reaching up to 70% in adolescents. SUMMARY Klinefelter's syndrome (47, XXY) causes hypogonadotophic hypogonadism and severe oligospermia/azoospermia rendering natural conception rare. During puberty, boys often require testosterone replacement therapy to develop secondary sexual characteristics, which can further decrease spermatogenesis. There is a progressive decrease of testicular germ cells after the onset of puberty, suggesting that fertility evaluation and preservation should begin shortly thereafter. In adolescents desiring fertility evaluation, any testosterone therapy should be discontinued, hormones and gonadotrophins measured, and a semen analysis obtained. Adolescents with low testosterone are administered aromatase inhibitors, selective estrogen receptors modulators and/or human chorionic gonadotropin to increase endogenous testosterone production. After testosterone levels are normalized, semen analysis is performed, and cryopreservation encouraged if sperm is present. For those without sperm in the ejaculate, a testicular sperm extraction is offered.