What is Niemann-Pick Disease?

Niemann-Pick disease (NP) refers to a group of inherited metabolic disorders known as the leukodystrophies or lipid storage diseases in which harmful quantities of a fatty substance (lipids) accumulate in the spleen, liver, lungs, bone marrow, and the brain. Symptoms may include lack of muscle coordination, brain degeneration, learning problems, loss of muscle tone, increased sensitivity to touch, spasticity, feeding and swallowing difficulties, slurred speech, and an enlarged liver and spleen. There may be clouding of the cornea and a characteristic cherry-red halo develops around the center of the retina. The disease has 4 related types. Type A, the most common type, occurs in infants. It is characterized by jaundice, an enlarged liver, and profound brain damage. Children with this type rarely live beyond 18 months. Type B involves an enlarged liver and spleen, which usually occurs in the pre-teen years. The brain is not affected. In types A and B, insufficient activity of an enzyme called sphingomyelinase causes the build up of toxic amounts of sphingomyelin, a fatty substance present in every cell of the body. Types C and D may appear early in life or develop in the teen or adult years. Affected individuals have only moderate enlargement of the spleen and liver, but brain damage may be extensive and cause an inability to look up and down, difficulty in walking and swallowing, and progressive loss of vision and hearing. Types C and D are characterized by a defect that disrupts the transport of cholesterol between brain cells. Type D usually occurs in people with an ancestral background in Nova Scotia.

What is the prognosis?

Infants with type A die in infancy. Children with Type B may live a comparatively long time, but may require supplemental oxygen because of lung impairment. The life expectancy of persons with types C and D varies: Some individuals die in childhood while others, who appear to be less severely affected, live into adulthood.

What research is being done?

The National Institute of Neurological Disorders and Stroke (NINDS), a part of the National Institutes of Health (NIH), conducts research about Niemann-Pick disease in laboratories at the NIH and also supports additional research through grants to major medical institutions across the country. Investigators at the NINDS have identified two different genes that, when defective, contribute to Niemann-Pick disease types C and D.