Definition:
Niemann-Pick Disease Type C is very different than Type A or B.  It is caused by an inability to transport cholesterol and other lipids properly within the cell, whereas Type A and Type B are caused by an enzyme deficiency that leads to an accumulation of a specific lipid inside the cell. Consequently in Type C, excessive amounts of cholesterol accumulate within the liver and spleen, and excessive amounts of other lipids accumulate in the brain.

The incidence of Niemann-Pick Disease Type C is estimated to be 1 in 150,000 people worldwide.  There is a higher incidence of Niemann-Pick Type C among the Spanish-American population of southern New Mexico and Colorado.

The classic form of Niemann-Pick Disease Type C is more than half of all Niemann-Pick Disease Type C cases. There are infantile and adult forms of this disorder.

The gene designated NPC 1 was identified in 1997.  Mutations in this gene cause approximately 95 percent of Niemann-Pick Disease Type C cases.  A second gene, NPC 2, was identified in 2000.  This accounts for the remaining cases of Niemann-Pick Disease Type C.  

Symptoms:
The age of symptom onset and the rate at which the disorder progresses vary widely for Niemann-Pick Type C.  Symptoms may appear as early as a few months of age or as late as adulthood. Symptoms include the inability to move one’s eyes up and down, an enlarged liver or spleen, or jaundice. In early stages of this disease, commonly one or two symptoms may appear.  Typically, neurological symptoms begin appearing between the ages of 4 and 10.  Generally, the later the onset of neurological symptoms, the slower the disorder will progress.

Symptoms for individuals who have a form of Niemann-Pick Disease Type C that occur later in childhood or in early adulthood are marked by psychiatric symptoms, slowing of speech, and ataxia or uncoordinated mobility.  

Inheritance Pattern:
Niemann-Pick Type C is an autosomal recessive disorder.

Life Expectancy:
Life expectancy for individuals with the infantile form of Niemann-Pick Type C is younger than 20 years of age. Individuals with the adult form can live into adulthood.

Diagnosis and Testing:
A diagnosis of Niemann-Pick Type C is made using cells cultured from a skin biopsy.  The tests performed include measurement of cholesterol esterification and staining to show the accumulation of free cholesterol within cells.  

More than 250 mutations have been identified in the NPC 1 and 2 genes.  As a result, the diagnosis cannot be made by direct molecular testing although this is used to confirm the biochemical disgnosis described above.

Treatment:
There is no curative treatment recognized for Niemann-Pick Type C.  A trial of low cholesterol diet and cholesterol-lowering medications does not appear to influence the course of disease, and studies have shown no affect on the neurological progression.  More recently, a trial of substrate reduction therapy has shown promising result.

Patient Groups:
Ara Parseghian Medical Research Foundation
3530 E. Campo Abierto, Suite 105
Tucson, AZ 85718
www.parseghian.org
tel: (520) 577-5106
fax: (520) 577-5212
Glen Shepherd, Executive Director
gshepherd@parseghian.org

National Niemann-Pick Disease Foundation
P.O. Box 49
401 Madison Ave. Ste B
Fort Atkinson, WI 53538
www.nnpdf.org
tel: (920) 563-0930
fax: (920) 563-0931
Nadine Hill, Director of Family Services
nnpdf@nnpdf.org

National Tay-Sachs & Allied Diseases Association
2001 Beacon Street, Suite 204
Boston, MA 02135
www.ntsad.org
tel: (800) 906-8723
fax: (617) 277-0134
Sue R. Kahn, Executive Director
info@ntsad.org