Carrier screening or diagnostic testing for Niemann-Pick disease type A for individuals of Ashkenazi Jewish descent.
- Patient Preparation
- Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 1 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Plasma or serum. Specimens collected in sodium heparin or lithium heparin tubes.
- Ambient: 72 hours; Refrigerated: 2 weeks; Frozen: 1 month
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.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|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