Distinct Niemann-Pick Disease Type C Clinical, Cytological, and Biochemical Phenotype in an Adult Patient With 1 Mutated, Overexpressed NPC1 Allele

Abstract Niemann-Pick disease type C (NP-C) is a rare autosomal-recessive neurovisceral lysosomal storage disease. We report on a juvenile onset, now 25-year-old female patient with typical neurologic symptoms, including vertical gaze palsy, of NP-C. The diagnosis was supported by a positive filipin test (“variant biochemical phenotype” of cholesterol accumulation) in cultured fibroblasts, high numbers of “Niemann-Pick cells” in the bone marrow, and 1 positive out of 3 NP-C biomarkers tested, but NP-C was not definitely confirmed genetically. She showed only 1 known NPC1 variant (3 bp ...