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Niemann Pick Disease Type A and B: SMPD1 Recurrent Mutations

Alternate test name

Sphingomyelinase Deficiency

Gene name / Alternate gene name
  • SMPD1
  • ASM; NPD
Sphingomyelin phosphodiesterase 1, acid lysosomal
Lab area
Genome Diagnostics - Molecular Genetics
Method and equipment
Targeted analysis of recurrent muations
Expected turn-around time
Pregnancy/STAT: 2-3 weeks Routine: 4-6 weeks
Specimen type

Blood; gDNA. 

For details about specimen requirements, please refer to: Specimen Type & Requirements (PDF).

Specimen requirements

5-10 mL EDTA or ACD 0.5 mL EDTA (neonate); minimum 10 ug in 100 uL low TE (pH8.0)

Storage and transportation

Room Temperature

For details about specimen requirements, please refer to: Specimen Type and Requirements

Special requirements

Special Instructions for Genome Diagnostics Samples

If sample shipment >48 hours, ship on ice.

Shipping information
The Hospital for Sick Children
Division of Genome Diagnostics
555 University Avenue, Black Wing, Room 3416
Toronto, ON
M5G 1X8
Phone: 416-813-7200 ext. 2
Hours: Monday to Friday, 8 a.m. to 4:30 p.m.
Off hours: Please send to Rapid Response Laboratory, 555 University Avenue, Room 3642
Email Molecular Lab:
Email Cytogenetics:
Background and clinical significance

Niemann disease types A and B (NP) are lysosomal storage disorders resulting from the accumulation of sphingomyelin, cholesterol and other lipids in the cells of affected individuals due to a deficiency of sphingomyelinase activity. Niemann Pick type A (NPA) presents in infancy with organomegaly and rapid neurodegeneration leading to death by ~3 years of age. Niemann Pick type B (NPB) is clinically heterogeneous and individuals can present with multiple findings including hepatosplenomegaly, growth delay, frequent respiratory infections, fatigue and hematologic abnormalities. Individuals with NPB usually survive into adulthood. DNA testing for three mutations common in the Ashkenazi Jewish population for NPA and one mutation in NPB is performed. NP is an AR disorder caused by mutations in the SMPD1 gene, located on chromosome 11 (11p15.4). Four mutations in the SMPD1 gene account for greater than 95% of the mutations seen in AJ individuals affected with Niemann Pick disease, type A & B.

See related information sheet: Ashkenazi Jewish Screening Panel

Disease condition

Niemann Pick Disease Type A and B (part of the Ashkenazi Jewish screening panel)

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