Niemann-Pick Disease, Type C (NPC1-Related) (NPC1)
Niemann-Pick disease, type C (NPC1-related) is an autosomal recessive, pan-ethnic neurodegenerative disorder that is caused by pathogenic variants in the gene NPC1. The classic presentation includes spastic ataxia and seizures that begin between the ages of 2 and 4, often after a period of normal development. Progressive deterioration leads to the loss of previously learned speech, dystonia that eventually prevents oral feeding, and dementia. Most patients die in adolescence. Some patients may present in infancy with liver and lung problems, many of whom die in infancy. Occasionally, patients can present in adolescence or adulthood with neurologic manifestations. Several specific variants may be associated with the development of either the severe infantile or typical juvenile form, but some variants may not be associated with a known genotype-phenotype correlation.
For information about carrier frequency and residual risk, please see the residual risk table.