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Niemann-Pick Disease

Group of storage disorders

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Updated October 04, 2013

Niemann-Pick disease

The brain and nervous system are affected in Niemann-Pick disease Types A, C, and D

Photo © A.D.A.M.

Niemann-Pick disease refers to a group of inherited disorders known as leukodystrophies, or lipid storage disorders, in which certain fats accumulate in the tissues like the brain and liver and cause damage. In Niemann-Pick disease, the body is unable to break down fats completely so they accumulate in the tissues and cause damage.

Certain groups have higher risk

Niemann-Pick disease affects all groups of people and both males and females. However, certain populations have a higher incidence of the disease:
  • Ashkenazi Jewish population (Types A and B)
  • French Canadian population of Nova Scotia (Type D)
  • Maghreb region (Tunisia, Morocco, Algeria) of North Africa (Type B)
  • Spanish-American population of southern New Mexico and Colorado (Type C)
The four types of Niemann-Pick disease are commonly called Type A, Type B, Type C, and Type D. Sometimes Type A and B are grouped together as Type I and C and D are grouped together as Type II.

Niemann-Pick Type A

  • Caused by deficiency of the enzyme acid sphingomyelinase (ASM) which is needed to break down a type of fat called sphingomyelin
  • Usually less than 1% of the normal level of the enzyme present in the body
  • This leads to accumulation of a fat (sphingomyelin) which damages cells
  • Causes severe nervous system disease
  • Usually leads to death usually by 18 months to 2 years of age
  • Most cases (85%) of Neimann-Pick are Type A

Niemann-Pick Type B

  • Like Type A is caused by deficiency of acid sphingomyelinase (ASM), but less servere
  • In Type B, there is usually about 10% of the normal level is present in the body
  • Leads to accumulation of sphingomyelin which damages cells
  • Little or no neurological problems
  • Longer life expectancy than the other types--into adulthood

Neimann-Pick Types C and D

  • Caused by inability to break down or transport cholesterol
  • Leads to accumulation of cholesterol and other fats in the liver, spleen, and brain
  • Nervous system disease develops
  • Leads to death usually by age 20
  • Most rare type of Niemann-Pick (possibly 500 cases worldwide)

Symptoms

One of the difficulties in correctly diagnosing Niemann-Pick disease is that its symptoms can be different in each person affected. Types A and C may have symptoms such as:
  • enlarged liver
  • brain damage
  • difficulty walking and swallowing
  • increased sensitivity to touch
  • difficulty speaking
  • loss of muscle tone (hypotonia)
  • learning difficulties
Type B does not have the nervous system symptoms. People with Type B often have repeated respiratory infections and an enlarged liver and spleen.

Diagnosis

Types A and B can be diagnosed by measuring the ASM activity in white blood cells. Low levels would point to Niemann-Pick disease. Type C can be diagnosed by examining a skin sample (biopsy) for cholesterol storage.

Treatment

As yet, there are no specific treatments for any of the types of Niemann-Pick disease. Bone marrow transplant has been attempted in several individuals with Type B. People with Types C and D are often placed on a low-cholesterol diet. Supportive care through nutrition, medication, physical therapy, and being followed by specialists can help with quality of life.

Sources:

"NINDS Niemann-Pick Disease Information Page." Disorders A - Z. 18 June 2007. National Institute of Neurological Disorders and Stroke. 20 Feb 2009.

"Disease Overview." Niemann-Pick Disease. National Niemann-Pick Disease Foundation. 20 Feb 2009.

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