[The genetics of hypogonadotropic hypogonadism in the male].

Underlying causes of hypogonadotropic hypogonadism are acquired or congenital disorders of the hypothalamus or pituitary (e.g. pituitary adenoma, craniopharyngioma, prior radiotherapy, trauma, severe general diseases, extreme stress, genetic mutations). In addition to a comprehensive history and physical examination, the diagnostic work-up includes measurement of testosterone, LH and FSH, with the aim of differentiating between primary and secondary hypogonadism. Where indicated, investigation of pituitary function, the use of imaging procedures, possibly an olfactory test, a GnRH stimulation test or genetic analyses may be added. Depending upon the indication, treatment is effected with testosterone, GnRH or gonadotropines.