Klinefelter Syndrome

The study seeks primarily to determine whether modulation of systemic and testicular sex steroids balance by aromatase inhibitors will positively affect the metabolic health and spermatogenesis of men with Klinefelter syndrome (KFS) as compared to the current state of the art for each issue. Secondary objectives of this study are (i) to unravel the heterogeneity of the reproductive and metabolic phenotype of men with KFS by performing a multi-omic analysis in a large cohort at baseline; (ii) to evaluate the efficacy of semaglutide-induced weight loss to achieve metabolic and reproductive benefit in men with Klinefelter syndrome as compared to standard testosterone replacement; (ii) to assess whether addition of hCG to aromatase inhibitors further increases intratesticular testosterone and promotes spermatogenesis in men with KFS.

This is a longitudinal retrospective study for the evaluation of thyroid function and structure in patients with Klinefelter syndrome compared to healthy controls and patients affected by chronic lymphocytic thyroiditis.

The goal of this randomized clinical trial is to study the effect of testosterone replacement therapy during puberty in boys with Klinefelter syndrome (KS, 47,XXY). The main questions to answer are how treatment with testosterone will affect body fat mass, lipid and glucose metabolism, growth and body proportions, bone mineralization as well as effects on neurocognitive development and emotional and social difficulties. Participants will be randomized to two years treatment with testosterone or placebo.

This study is designed to research the natural history of neurodevelopment, health and early hormonal function in infants with XXY/Klinefelter syndrome, XYY, XXX and other sex chromosome variations in an effort to identify early predictors of developmental and health outcomes. The Investigators will also evaluate different developmental screening tools in infants with sex chromosome variations so the investigators can develop recommendations for pediatrician caring for infants and young children with XXY/Klinefelter syndrome, XYY, XXX, and other sex chromosome variations.

Transition from paediatric to adult endocrinology is a challenge for adolescents, families and doctors. Up to 25% of young adults with chronic endocrine disorders are lost to follow-up ('drop-out') once the young adult moves out of paediatric care. Non-attendance and sub-optimal medical self-management can lead to serious and expensive medical complications. In a pilot study, adolescents suggested the use of e-technology to become more involved in the transition process. The investigators have designed and developed the YESS! game, a tool to help improve medical self-management in adolescents with chronic endocrine disorders. The hypothesis is that adolescents playing the YESS! game will show a larger increase in self-management score during the first year of transition and will have a lower drop-out rate at the adult endocrine outpatient clinic (OPC), compared to adolescents who do not play the game.