title: A rare case of Niemann-Pick disease type C without neurological involvement in a 66-year-old patient.
abstract: The case of a 66 year-old female - the oldest known living patient with Niemann-Pick disease type C (NP-C) who remains free of any neurological or psychiatric manifestations 18 years after presentation - is presented. An incidental finding of massive splenomegaly was detected during a routine pelvic ultrasound. The pathology report after splenectomy showed the presence of lipid-laden macrophages. Fibroblasts cultured in LDL-enriched medium revealed abnormal filipin staining consistent with cholesterol-filled vesicles and the rate of cholesterol esterification in response to stimulation of LDL-cholesterol uptake was significantly depressed at 6% of that seen in cells from normal controls, but at a level similar to that observed in an NP-C positive control. Molecular genetic testing later revealed a compound heterozygous mutant NP-C genotype comprising two previously described disease-causing mutations in the NPC1 gene, one in exon 8 (c.1133T>C [V378A]) and one in exon 13 (c.1990G>A [V664M]). These findings confirmed the diagnosis of NP-C. Only three patients with this disorder aged > 53 years have previously been reported, all of whom presented with neurological or neuropsychiatric manifestations. Our patient is the first reported NP-C patient, now in her seventh decade of life, who has to date only manifested splenomegaly. This case highlights the extreme clinical variability of NP-C, and the need to consider this disease in the differential diagnosis of organomegaly, even in the absence of neurological, psychiatric and related clinical signs.
  
  
  CONCLUSIONS
  An elderly female patient with confirmed NP-C and isolated splenomegaly has remained asymptomatic for neurological, cognitive, psychiatric or ophthalmologic abnormailities into her seventh decade of life.
authors.affiliation: Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Canada.
authors.forename: C R
authors.initials: CR
authors.lastname: Greenberg
authors.affiliation: Department of Neurology, University of Manitoba, Winnipeg, Canada.
authors.forename: J G
authors.initials: JG
authors.lastname: Barnes
authors.affiliation: Department of Ophthalmology, University of Manitoba, Winnipeg, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Kogan
authors.affiliation: Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Canada; Diagnostic Services Manitoba, Winnipeg, Canada.
authors.forename: L E
authors.initials: LE
authors.lastname: Seargeant
keywords: Asymptomatic; Niemann–Pick disease type C (NP-C); Organomegaly; Splenomegaly