Visceral symptoms as a key diagnostic sign for the early infantile form of Niemann–Pick disease type C in a Russian patient: a case report

A 5-year-old white boy born to non-consanguineous Russian parents was originally diagnosed with galactosemia at the age of 2 months based on a raised blood galactose level. A galactose-free and lactose-free diet resulted in achievement of a normal galactose level, but hepatosplenomegaly and cholestatic signs persisted. Liver biopsy results hinted at possible Niemann–Pick disease type C, but differential diagnostic investigations for progressive familial intrahepatic cholestasis type 2 (Byler syndrome) indicated a heterozygous genotype suggestive of this disease. Further, progressive neurological symptoms prompted additional genetic analyses for possible Niemann–Pick disease type C, from which an as-yet unreported combination of known NPC1 gene mutations was identified, and a final diagnosis of Niemann–Pick disease type C was established. The patient subsequently developed typical neurological symptoms of early-infantile Niemann–Pick disease type C, including vertical supranuclear ophthalmoparesis and cerebellar ataxia. Miglustat therapy was initiated 2.5 years ago, and some improvements in movement and speech have since been observed.