[Cataplexy in type C Niemann-Pick disease].

Cataplexy usually occurs as a part of the tetrad of clinical phenomena of idiopathic narcolepsy. Symptomatic cases are rare. A 4 years old girl from consangineous parents had recurrent loss of muscle tone and fell to the ground, when she laughed. The EEG was normal. Prolonged neonatal jaundice with cholestasis, hepatosplenomegaly, mental regression, supranuclear ophthalmoplegia, and foam cells led to the diagnosis of Niemann-Pick disease type C with symptomatic cataplexy. Symptomatic forms of the narcolepsy-cataplexy complex should be considered, when there is an early onset before puberty, cataplectic attacks predominate the narcoleptic attacks, and when additional neurological symptoms occur. Symptomatic cataplexy occurs in Niemann-Pick disease type C. It is considered to be the result of lesions of the pontine reticular formation.