Prader-Willi syndrome, diabetes mellitus and hypogonadism.

Diabetes mellitus is not a diagnostic criterion for Prader-Willi syndrome (PWS), but it is often found in PWS patients. The etiology for diabetes mellitus in PWS may be related to the morbid obesity and consequent insulin resistance, because a decrease of oxytocin neurons and leptin resistance in PWS may cause hyperphagia, inducing obesity. However, treatment with growth hormone (GH) is beneficial for the majority of GH-deficient PWS children, because relative decreased fat mass and increased fat-free mass could prevent obesity and concomitant insulin resistance. Hypogonadism is thought to be due to hypogonadotrophic hypogonadism in a majority of PWS patients. Hypergonadotrophic hypogonadism secondary to cryptorchidism and its treatment is shown in other cases. Low luteinizing hormone and high follicle-stimulating hormone levels in PWS cases in young men with idiopathic oligospermia or in the early stages of puberty is less frequently reported.