Clinical review 4: Diagnosis and treatment of isolated gonadotropin-releasing hormone deficiency in men.

The clinical association of absent sexual maturation with anosmia was first described by Kallmann in 1944 Since then, other midline defects such as cleft lip and palate, cranial nerve defects, and color blindness have been associated with this condition and hypogonadotropic hypogonadism added when gonadotropin determinations became available. Subsequent anatomical studies from autopsies of affected patients, and more recently computed tomography (CT) and magnetic resonance imaging (MRI), have failed to demonstrate associated abnormalities within the hypothalamic-pituitary region. Detailed endocrine evaluation of hypothalamic- pituitary function have confirmed that the functional defect to is limited to GnRH secretion in this syndrome. The subsequent successful stimulation of pituitary release of LH and FSH by synthetic GnRH demonstrated that the defect in these individuals was hypothalamic and not pituitary in origin. Early attempts at reversing GnRH deficiency with the infrequent administration of contin...