[Sphingomyelinase activity in a patient with Niemann-Pick disease].

In a few months old baby a visceromegaly was found, without other clinical abnormalities. Using an artificial substrate a deficiency of sphingomyelinase could not be demonstrated. Histopathological examination of biopsied liver revealed a lipid storage disease. Using the natural substrate the deficiency of sphingomyelinase could be demonstrated in leucocytes and in cultured fibroblasts.