Carrier screening or diagnostic testing for Niemann-Pick disease type A for individuals of Ashkenazi Jewish descent.
Polymerase Chain Reaction/Fluorescence Monitoring
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
Transport 3 mL whole blood. (Min: 1 mL)
Plasma or serum. Specimens collected in sodium heparin or lithium heparin tubes.
Ambient: 72 hours; Refrigerated: 2 weeks; Frozen: 1 month
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.
Laboratory Developed Test (LDT)
|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|
- SMPD1 mutation assay