CATAPLEXY AND MONOAMINE-OXIDASE DEFICIENCY IN NORRIE DISEASE

Norrie disease (ND) is an X-linked recessive disorder causing ocular a trophy, mental retardation, deafness, and dysmorphic features. Virtual ly absent monoamine oxidase (MAO) type-A and -B activity has been foun d in some boys with chromosome deletions. We report the coexistence of cataplexy and abnormal REM sleep organization with ND. Three related boys, referred for treatment of medically refractory atonic spells and apneas, underwent extended EEG-video-polysomnographic monitoring. The y demonstrated attacks of cataplexy and inappropriate periods of REM s leep during which they were unarousable. One boy also had generalized tonic-clonic seizures. Previous testing revealed that all three have c omplete ND gene deletions. In all subjects, platelet MAO-B activity wa s absent, serum serotonin levels were markedly increased, and plasma c atecholamine levels were normal. Data from the canine narcolepsy syndr ome model implicate abnormal catecholaminergic and cholinergic activit ies in the pathogenesis of cataplexy. Our findings suggest that abnorm al MAO activity or an imbalance between serotonin and other neurotrans mitter levels may be involved in the pathogenesis of human cataplexy.