Description: Niemann-Pick Type A disease is a severe neurodegenerative disorder of infancy. By six months of age, affected babies experience feeding difficulty, recurrent vomiting and enlargement of the spleen and liver, which causes the abdomen to appear distended. Some children with the disease have a "cherry-red spot" in the retina of the eye. Death usually occurs between age 2-4. One in 75 Ashkenazi Jews are carriers of Neimann-Pick Type A disease.
Symptoms:
- 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
- Usually a baby with Niemann-Pick Type A Disease dies by the second year of life
Cause: Niemann-Pick disease is inherited in an autosomal recessive manner. When both parents are carriers of the gene mutations, there is a 1 in 4 (25%) chance in each pregnancy to have an affected child. The specific biochemical defect in Type A Niemann-Pick disease is the deficiency of an enzyme, sphingomyelinase (ASM), which normally degrades a fatty substance known as sphingomyelin. The enzyme defect leads to the accumulation of sphingomyelin, primarily in the liver, spleen, lymph nodes, and brain.
Treatment: There is currently no treatment or cure for Neimann-Pick Type A disease.
Disease Frequency: There are approximately 1,200 Type A or Type B cases diagnosed world wide. It has been estimated that approximately two-thirds of all infants with Niemann-Pick Type A disease are of Ashkenazi Jewish descent.
Carrier Frequency: Approximately one in 75 Ashkenazi Jews is a carrier of Neimann-Pick Type A disease.
Diagnosis: Diagnosis of people affected with Neimann-Pick Type A and B can be achieved by testing blood and measuring the ASM activity in the white blood cells.
Screening: Carrier screening requires a sample of blood to determine whether or not a gene change is present in the gene for Neiman-Pick. Prenatal screening, via CVS (Chorionic Villus Smmpling) or Amniocentesis, can be performed early in the pregnancy.
History: The first case of infantile-onset Niemann-Pick disease was described in 1914 by the German neurologist Albert Niemann. Niemann described a young child with an enlarged liver and spleen, enlarged lymph glands, swelling and a darkening of the skin of the face. The child had brain and nervous system impairment and died before the age of two. Later, in the 1920's, Luddwick Pick studied tissues after the death of such children and provided evidence of the new disorder.
Future: In 1997, the gene responsible for Niemann-Pick disease was discovered. This discovery has helped focus research for treatments.
Gene therapy has shown effectiveness in mice for Niemann-Pick Type A disease.
