ESPEYB21 6. Differences of Sexual Development (DSD) and Gender Incongruence (GI) New Clinical Insights into Klinefelter Syndrome (3 abstracts)
J Clin Endocrinol Metab. 2023 Sep 18;108(10):2486-2499. doi: 10.1210/clinem/dgad205. PMID: 37043499
Brief Summary: This longitudinal study provides an in-depth analysis of the clinical, endocrine, and testicular ultrasound (US) patterns in Klinefelter Syndrome (KS) from infancy through puberty and into adulthood, highlighting the progression of testicular degeneration in these patients.
In this study, 155 KS patients with the classical 47,XXY karyotype, aged 7 months to 55 years, were prospectively evaluated at a single referral center following a standardized protocol. Key findings were:
Hormonal indicators of Sertoli and germ cell impairment emerge during Tanner stages 3 to 4. INHB levels remain normal until stage 4, after which a decrease in the INHB/FSH ratio is observed. FSH levels begin to rise at Tanner stage 2, more than LH levels. Although nearly all adult patients develop a hypergonadotropic state with compensated hypoandrogenism, impaired testosterone secretion is generally not seen in boys with KS during puberty. A reduced plasma testosterone/LH (T/LH) ratio may indicate Leydig cell dysfunction, even if plasma testosterone levels appear normal. The T/LH ratio peaks during Tanner stages 2 to 3, then declines from stage 4 onward. Testosterone levels increase until Tanner stage 4, then begin to regress. There is no hormonal evidence of testicular dysfunction (in terms of gonadotropins, testosterone and inhibin B) between mini-puberty and late prepuberty. Testicular volume increases from Tanner stage 2 to stage 4, with testicular degeneration becoming evident at the end of puberty (stage 5) and continuing into adulthood. Quantitative ultrasound measures, including echotexture and the presence of hypoechoic lesions and microlithiasis, are significant predictors of poor testicular endocrine function and they worsen through puberty and into the transition age, indicating ongoing gonadal compromise.
Further research is needed to assess the effectiveness of testicular ultrasound (US) in predicting outcomes for KS patients such as the chance of successful sperm retrieval and the optimal timing for therapeutic interventions. Integrating US findings with histological analysis and advanced hormone assays should help in optimizing patient care and improving long-term outcomes.