Impact of age at first visit on glycolipid metabolism, bone metabolism, and fertility potential in patients with Klinefelter syndrome

Background: Classic Klinefelter syndrome (KS) is characterized by one extra X chromosome (47, XXY), leading to hypergonadotropic hypogonadism and higher risk of alterations in glycolipid homeostasis, cardiovascular diseases, and low bone mineral density. Most frequently, KS is diagnosed in adulthood because of infertility. Objectives: To investigate the potential association between the age at first visit and the presence of comorbidities in patients with KS. Materials and Methods: In this cross-sectional retrospective study, we analyzed the data from 445 patients affected by non-mosaic 47, XXY KS and aged less than 50 years. Anthropometric measurements, biochemical and hormonal tests, semen analysis, scrotal echo-color Doppler, and dual energy X-ray absorptiometry (DXA) were performed on the patients. A subset of patients underwent testicular sperm extraction (TESE). Results: Age at first visit significantly correlated positively with waist circumference (WC), body mass index (BMI), blood glucose, glycated hemoglobin, total cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides, and negatively with total testosterone (TT), calculated free testosterone (cFT), calcium, phosphorus, vitamin D, and lumbar Z-score. Age at the first visit >26 years was associated with higher frequency of increased WC, BMI, and hypercholesterolemia. Among the 199 patients who underwent testicular biopsy, the mean retrieval rate was 36.2% and was higher in the younger group (<26 years). Discussion and Conclusion: Early diagnosis and management of KS is important for preventing or reducing comorbidities later in life. In particular, glycemic, lipid, and phospho-calcium metabolism worsen with advancing age at first visit. Furthermore, early management of the patient seems to be associated with a higher probability of recovering spermatozoa through TESE.