From mini-puberty to pre-puberty: early impairment of the hypothalamus–pituitary–gonadal axis with normal testicular function in children with non-mosaic Klinefelter syndrome
Purpose: Klinefelter syndrome (KS) is a genetic disorder caused by the presence of an extra X chromosome in males. The aim of this study was to evaluate the hypothalamic–pituitary–gonadal (HPG) axis and the clinical profile of KS boys from mini-puberty to early childhood. Patients and methods: In this retrospective, cross-sectional, population study, 145 KS boys and 97 controls aged 0–11.9 years were recruited. Serum FSH, LH, testosterone (T), Inhibin B (INHB), sex hormone binding globulin (SHBG) and anti-Müllerian hormone (AMH) were determined.