[A case of type C Niemann-Pick disease].

We diagnosed a 3-year-old boy as type C Niemann-Pick disease by studies on cultured fibroblasts; sphingomyelinase activity was almost normal, but esterification of exogenously administered cholesterol was deficient. Also sparse cultures of his fibroblasts developed a relatively intense fluorescence with filipin that was not observed either in normal or type B Niemann-Pick fibroblasts. We tried to treat him with dimethylsulfoxide (DMSO), 100 mg-120 mg/day for a year, but it had clinically insufficient effect on our case.