TN 3 (02-10)
DI 23022.475 Niemann-Pick Type C
NIEMANN-PICK DISEASE - TYPE C
NPD; NPC; NPD type C; Niemann-Pick type II; Sphingomyelinase deficiency; Neuronal Cholesterol Lipidosis
Neimann-Pick disease type C (NPC) is one of 5 types of NPD and is a genetic disorder that results in progressive loss of nervous system function by affecting the membranes of nerve cells. Mutations in either the NPC1 or NPC2 genes cause NPC. NPC may appear early in life or develop in the teen or adult years. At birth, the infant may have jaundice, feeding problems, dystonia (abnormal muscle contraction causing repetitive involuntary muscle movements), inadequate weight gain (failure to thrive) and developmental problems. They may 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, seizures, dementia, slurred and irregular speech and tremors.
TESTING, PHYSICAL FINDINGS, AND ICD-9-CM CODING
A skin biopsy and (if available) DNA genetic testing is used to diagnose NPC. Additional tests such as slit-lamp eye exam to assess vision loss, liver biopsy, MRI and psychometric testing.
ONSET AND PROGRESSION
The life expectancy of people with NPC varies. Some people die in childhood while others who appear to be less severely affected, live into adulthood. A child who shows signs of NPC before age 1 may not live to school age. Those who show symptoms after entering school may live into their mid-to-late teens, with a few surviving into the 20s.
There is currently no effective cure for this disease. Medicines are available to control or relieve many symptoms such as cataplexy and seizures.
SUGGESTED PROGRAMMATIC ASSESSMENT*
Suggested MER for Evaluation: Laboratory tests showing intravesicular cholesterol storage is diagnostic of this disorder. Molecular genetic testing utilizing sequence analysis that identifies mutations in either NPC1 or NPC2 gene. If laboratory testing or molecular genetic testing results have not been done or are non-diagnostic, then complete review of the clinical course and all of the laboratory data on which the disorder is suspected will need to be reviewed. To establish the severity of this disorder, complete physical, neurological, and mental examinations may be needed if one of these examinations alone is insufficient to meet a listing.
Suggested Listings for Evaluation:
| || |
* 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.