A syndrome, sometimes considered as three separate entities (Kalmann syndromes 1, 2, and 3), characterized mainly by reduced hypothalamic function and reduced pituitary gonadotropic activity and deficiency of gonadotropin-releasing hormone with resulting hypogonadism and absent or reduced sense of smell due to agenesis of the olfactory bulbs. Associated anomalies include cleft palate, neurosensory hearing loss, congenital heart defect, intestinal malrotation, renal agenesis, hypertension, mental retardation, color blindness, and other defects. Most abnormalities occur in types 1 and 2; type 3 is marked mainly by hypogonadotropic hypogonadism, anosmia, and craniofacial abnormalities.