Ordering Recommendation

Carrier screening or diagnostic testing for Niemann-Pick disease type A for individuals of Ashkenazi Jewish descent.

Mnemonic
SMPD1
Methodology

Polymerase Chain Reaction/Fluorescence Monitoring

Performed

Tue, Fri

Reported

5-10 days

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
Collect

Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).

Specimen Preparation

Transport 3 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions

Plasma or serum. Specimens collected in sodium heparin or lithium heparin tubes.

Remarks
Stability

Ambient: 72 hours; Refrigerated: 2 weeks; Frozen: 1 month

Reference Interval

By report

Interpretive Data

Background information for Niemann-Pick Type A (SMPD1), 4 Variants:
Characteristics:
Niemann-Pick type A is a lysosomal storage disease causing hepatosplenomegaly, delayed physical and mental development, hypotonia, rigidity, intellectual disability, and death typically by age 3.
Incidence: 1 in 32,000 Ashkenazi Jewish individuals.
Inheritance:
Autosomal recessive.
Cause:
SMPD1 pathogenic variants.
Variants Tested:
p.L304P (c.911T>C), p.F333Sfs (c.996delC), p.R498L (c.1493G>T), and p.R610del (c.1829_1831delGCC).
Clinical Sensitivity:
90 percent in Ashkenazi Jewish individuals, varies by ethnicity in non-Ashkenazi Jewish individuals.
Methodology:
Polymerase chain reaction (PCR) and fluorescence monitoring.
Analytical Sensitivity and Specificity:
Greater than 99 percent.
Limitations:
Variants other than those tested will not be detected.  Diagnostic errors can occur due to rare sequence variations.

Compliance Category

Laboratory Developed Test (LDT)

Note
Hotline History
N/A
CPT Codes

81330

Components
Component Test Code* Component Chart Name LOINC
0051460 Niemann-Pick Type A (SMPD1), Allele 1 32641-3
0051461 Niemann-Pick Type A (SMPD1), Allele 2
0051462 Niemann-Pick Type A (SMPD1), Interp 34518-1
2001335 Niemann-Pick Type A (SMPD1), Specimen
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • SMPD1 mutation assay
Niemann-Pick Type A (SMPD1), 4 Variants