Norm of Sphingomyelinase
Not clinically significant.
Colitis (chronic), Niemann-Pick disease, types A and B.
Description of Sphingomyelinase
Sphingomyelinase is an enzyme that acts as a catalyst in the metabolism of sphingomyelin. Sphingomyelin is a phospholipid ubiquitously distributed in all membranes of mammalian cells and in serum lipoproteins. Niemann-Pick disease is an autosomal recessive lysosome storage disease caused by sphingomyelinase deficiency. Massive tissue accumulation of sphingomyelin results. Two types of Niemann-Pick disease have been identified: type A is a severe, neurodegenerative infantile form leading to death by 4 years of age; and type B is a chronic, nonneuronopathic form. A subacute form, similar to type B but with mild neuronal involvement (retinal storage, peripheral neuropathy, mild neurologic changes, or psychiatric disorders), has also been identified. In this test, a skin biopsy is used to perform fibroblast tissue culture and fibroblast assay for sphingomyelinase activity.
Professional Considerations of Sphingomyelinase
Consent form NOT required.
- Obtain a skin punch biopsy setup and a sterile plastic cup.
- Cleanse the biopsy site with alcohol and allow it to air-dry.
- Obtain a skin punch biopsy with a 4-mm punch.
- Place the biopsy specimen in a sterile cup.
Client and Family Teaching
- A mild analgesic may be used for site tenderness.
- Contact the physician for redness, swelling, increasing tenderness, purulent drainage, or slow healing noted at the site.
- Genetic counseling must be provided for individuals and families undergoing genetic testing.
Factors That Affect Results
- Inadequate punch biopsy specimen may cause false-negative results.
- Timeliness of results depends on laboratory availability.