Sphingomyelin storage in a patient with myoclonus epilepsy as a main clinical symptom -- a varient in Niemann-Pick disease type C.

A patient with myoclonus epilepsy as a main clinical symptom was histopathologically diagnosed as a generalized sphingolipidosis. It was found that both sphingomyelin and globoside I fairly increased in kidney, heart, lung and liver. While, only sphingomyelin was found to increase in cerebral gray and white matters and cerebellum, but other lipids were within the normal range. Sphingomyelin accounted for 22% of the total phospholipids especially in cerebellum. No cholesterol ester and ganglioside GM2 or asialo GM2 were in particular found in the brain. Fatty acid compositions of phospholipids, glycosphingolipids and gangliosides were found to be normal. Judging from the sphingomyelin storage not only in visceral organs but also in brain tissues, it was proposed that this disease might be a variant in Niemann-Pick disease Type C, although an enzymatic assay of sphingomyelinase still remains.