Sorted By Test Name - Mayo Medical Laboratories

NPDKM
61116
NPD
mutations in individuals with abnormal enzyme activity and 1 or no mutations detected by the panel of
common mutations (NPD/85322). NPD/85322 Niemann-Pick Disease, Types A and B, Mutation Analysis
is also the recommended test for carrier screening. For diagnostic testing, SPHT/8481 Sphingomyelinase,
Fibroblasts or LDSBS/89406 Lysosomal Disorders Screen, Blood Spot should be performed prior to
targeted mutation analysis or full gene analysis.
Useful For: Confirmation of a diagnosis of Niemann-Pick disease type A or B Carrier screening in
cases where there is a family history of Niemann-Pick disease type A or B, but disease-causing mutations
have not been identified in an affected individual
Interpretation: An interpretive report will be provided.
Reference Values:
An interpretive report will be provided.
Clinical References: 1. Schuchman EH: The pathogenesis and treatment of acid
sphingomyelinase-deficient Niemann-Pick disease. J Inherit Metab Dis 2007 Oct;30(5):654-663 2.
McGovern MM, Schuchman EH: Acid sphingomyelinase deficiency. In GeneReviews (Internet). Edited
by RA Pagon, TD Bird, CR Dolan, et al. University of Washington, Seattle. 1993-2006 Dec 07 (updated
2009 June 25)
Niemann-Pick Disease, Types A and B, Known Mutation
Clinical Information: Niemann-Pick disease (types A and B) is an autosomal recessive lysosomal
storage disease caused by a deficiency of the enzyme acid sphingomyelinase. The clinical presentation of
type A disease is characterized by jaundice, progressive loss of motor skills, feeding difficulties, learning
disabilities, and hepatosplenomegaly. Death usually occurs by age 3. Type B disease is generally milder,
though variable in its clinical presentation. Most type B patients do not have neurologic involvement and
survive to adulthood. Mutations in the SMPD1 gene are responsible for the clinical manifestations of
Niemann-Pick disease types A and B. Although this disease is panethnic, it has a significantly higher
frequency in individuals of Ashkenazi Jewish and Northern African descent. The carrier rate for type A in
the Ashkenazi Jewish population is 1/90. There are 3 common mutations in the Ashkenazi Jewish
population: L302P, R496L, and fsP330, which account for approximately 97% of mutant alleles in this
population. The deltaR608 mutation accounts for approximately 90% of the type B mutant alleles in
individuals from the Maghreb region of North Africa and 100% of the mutant alleles in Gran Canaria
Island. The recommended test for carrier screening is NPD/85322 Niemann-Pick Disease, Types A and B,
Mutation Analysis, which tests for 4 of the most common SMPD1 mutations. For diagnostic testing,
SPHT/8481 Sphingomyelinase, Fibroblasts or LDSBS/89406 Lysosomal Disorders Screen, Blood Spot
should be performed prior to molecular analyses. Known mutation analysis of the SMPD1 gene should be
utilized to detect private mutations in individuals with a family history of rare SMPD1 alterations.
Useful For: Diagnostic confirmation of Niemann-Pick disease type A or B when familial mutations
have been previously identified Carrier screening of at-risk individuals when a mutation in the SMPD1
gene has been identified in an affected family member
Interpretation: An interpretive report will be provided.
Reference Values:
An interpretive report will be provided.
Clinical References: 1. Schuchman EH: The pathogenesis and treatment of acid
sphingomyelinase-deficient Niemann-Pick disease. J Inherit Metab Dis 2007 Oct;30(5):654-63 2.
McGovern MM, Schuchman EH: Acid sphingomyelinase deficiency. In GeneReviews (Internet). Edited
by RA Pagon, TD Bird, CR Dolan, et al: University of Washington, Seattle. 1993-2006 Dec 07 (updated
2009 Jun 25)
Niemann-Pick Disease, Types A and B, Mutation Analysis
85322
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