[Klinefelter's syndrome and Turner's syndrome. For a better management].

Klinefelter's syndrome (KS) affects one in 600 men and Turner's syndrome (TS), one in 2500 women. These 2 diseases are the most sex chromosome disorders characterized by one extra X in the SK male (47XXY) and the loss of an X in the girls with ST (45 X). Their common characteristic is the gonadal dysgenesis, which is the main cause of male or female infertility. Called "the forgotten syndrome", KS is under-diagnosed because apart from the large size, there are no dysmorphic features, along with a great ignorance of cognitive and language disorders in children. There are often comorbidities that lead to diagnosis such as autoimmune diseases or metabolic syndrome. TS is often diagnosed by the short stature. Management of Turner's girls has profoundly changed with Growth hormone therapy. There is an international consensus for a better management of associated diseases such as ORL, cardiac, renal, hepatic, autoimmune and metabolic diseases. Prenatal diagnosis allows early detection and management of cognitive deficiencies and of associated diseases.