COMPASSIONATE ALLOWANCE INFORMATION

NIEMANN-PICK DISEASE (NPD) - Type A

DESCRIPTION

Niemann-Pick disease (NPD) 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. NPD Type A, neurodegenerative form, occurs in infants. It is characterized by jaundice, an enlarged liver, and profound brain damage. In NPD Type A, 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.

ALTERNATE NAMES

Acute Neuronopathic form-type A-classic infantile form, Niemann Disease, Sphingomyelin Lipidosis, Sphingomyelinase Deficiency

DIAGNOSTIC TESTING AND CODING

NPD Type A is diagnosed by measuring the amount of acid sphingomyelinase (ASM) in white blood cells. The test can be done using a blood or bone marrow sample. Sphingomyelinase assays (analysis) can also be used. DNA tests can be done to diagnose carriers. Prenatal testing is available when a mutation is known to exist in the family.

TREATMENT

There is currently no effective treatment for persons with NPD Type A. Medicines are available to control or relieve many symptoms, such as cataplexy and seizures.

PROGRESSION

Infants with NPD Type A generally die by age 2 or 3.

SUGGESTED PROGRAMMATIC ASSESSMENT*

Suggested MER for Evaluation: Acid sphingomyelinase (ASM) activity level in blood or bone marrow white blood cells, physical findings of hepatosplenomegaly (enlarged liver and spleen), and evidence of neurodevelopmental regression and progressive delay.

Suggested Listings for Evaluation:

DETERMINATION

LISTING

REMARKS

Meets Listing

110.08B

Catastrophic congenital abnormalities or disease

Medical Equals

* Adjudicators may, at their discretion, use the Medical Evidence of Record or Listings suggested to evaluate the claim. However, the decision to allow or deny the claim rests with the adjudicator.

Last Updated: 9/30/08

Office of Disability Programs