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Neimann-Pick Disease

      · Symptoms of Neimann-Pick Type A
      · Symptoms of Neimann-Pick Type B
      · Diagnosis
      · Treatment
      · Incidence in People of Jewish Descent
      · Testing
      · Resources and More

There are four clinical types of Niemann-Pick Disease, all inherited.

Type A and Type B are caused by the lack of a substance called ASM-acid sphingomylinase which breaks down a substance called sphingomyeline. Lack of ASM causes buildup of sphingomyeline in certain cells and causes damage to the central nervous system, liver, and lungs.

Though both Type A and B are caused by deficiency of ASM, Type A, which is most prevalent, is a severe neurological disease that generally leads to death between two and three years of age. Type B has little or no neurological involvement and many survive into late childhood or adulthood.

Type C and D are also caused by excess deposition of sphingomyelin, as patients do not properly transport sphingomyelin and that too results in its accumulation of sphingomyeline. However, it is the A and B types of Neimann-Pick Disease that have a higher incidence in Ashkenazi Jews, compared to the general population.

 

Symptoms of Neimann-Pick Type A
The prognosis of Type A is dismal, and usually a baby with this form of Niemann-Pick Disease succumbs by the second year of life. Symptoms and signs of Type A include:
      · Abdominal distention
      · Coordination and motor-skill difficulties
      · Feeding problems
      · Progressive spasticity
      · Blindness
      · Enlarged liver, and\or spleen
      · A “ cherry red spot” in the eye, visible by special eye exam.
      · May also present with jaundice in infancy and progressive liver failure.

Symptoms of Neimann-Pick Type B
Neimann-Pick Type B is less extreme and does not affect the brain. However, it does cause liver, spleen, lymph node, and bone marrow problems and generally leads to abdominal distention and respiratory difficulties.

Diagnosis
Diagnosis is achieved by testing blood, and measuring the ASM activity in the white blood cells. This test is effective in identifying persons actually victims of Type A and B but is not reliable in detecting persons who are carriers of Neimann-Pick.

Treatment
Currently Mount Sinai Hospital in New York in conjunction with Genzyme Corporation is working on new treatment modes for Type B Neimann-Pick Disease. They will be focusing on Enzyme Replacement Therapy and Gene Therapy.
 
Incidence in People of Jewish Descent
One in 75 Ashkenazi Jews is a carrier.
The disease is transmitted through heredity. Both parents have to carry the Neimann-Pick gene for there to be a possibility of transmission to their child. If both parents are carriers then:
      · There is a one in four chance that the child will inherit the Neimann-Pick gene from each parent and have the disease
      · There is a one in four chance that the child will inherit normal genes from both parents and be completely free of the disease.
      · There is a two in four chance the child will inherit one of each kind of gene and be a carrier like the parents, and free of the disease.
      · Unaffected siblings have a two in three chance of being carriers.

 

Testing
There is a carrier screening test which requires a sample of blood that can determine whether or not a gene change is present in the gene for Neiman-Pick.

Prenatal diagnosis for Neimann-Pick can be attained with the use of CVS (Chorionic Villus Smmpling) or Amniocentesis, which are performed early in the pregnancy.

Resources and More
     National Neiman-Pick Disease Foundation, Inc.
     3734 East Olive Avenue
     Gilbert, AZ 85234
     Telephone: 602-497-6638
     Website:http://www.nnpdf.org