[Diagnosis of adult type of Niemann-Pick disease (type C) in two brothers by filipin staining of bone marrow smears].

Niemann-Pick disease, type C (NPC) is a neurometabolic genetic disorder that is distinguished from other types of Niemann-Pick disease by its later onset, more insidious progression, variable visceromegaly, and abnormalities of intracellular cholesterol metabolism. We report cases in 18-year-old and 20-year-old brothers who presented with disinhibition and involuntary movement of their hands. Both brothers presented various signs such as dementia, vertical supranuclear ophthalmoplegia (VSO), dysarthria, axial and limb dystonia, hyperreflexia, pathologic reflex, cerebellar ataxia, as reported. They also presented startle response. Brain MRI showed diffuse cerebral atrophy and abdominal CT reveals hepato-splenomegaly in both patients. These cases were suspected to be NPC based on dementia, VSO, cerebellar ataxia, hepato-splenomegaly and foam cells in the bone marrow. Generally, the diagnosis of NPC is based on deficient cholesterol esterification and excessive lysosomal filipin staining in cultured skin fibroblasts. However, culture of fibroblasts obtained from a biopsied skin samples is slow. We have rapidly made the diagnosis of NPC in our patients by filipin staining of foam cells from bone marrow. This diagnostic process using a bone marrow smear is more convenient and rapid than previous methods using cultured skin fibroblasts.