Carrier screening or diagnostic testing for NEB-related nemaline myopathy 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: NEB-related nemaline myopathy typically presents within the first year of life with hypotonia, feeding difficulties and muscle weakness of the face, neck, arms and legs. Muscle weakness is static or progresses very slowly, but lifespan is not usually decreased.
Incidence: 1 in 47,000 in Ashkenazi Jewish individuals.
Inheritance: Autosomal recessive.
Cause: NEB pathogenic variants.
Variant Tested: Exon 55 del (p.R2478_D2512del).
Clinical Sensitivity: 99 percent in Ashkenazi Jewish individuals; unknown in other ethnicities.
Methodology: Polymerase chain reaction (PCR) and fluorescence monitoring.
Analytical Sensitivity and Specificity: Greater than 99 percent.
Limitations: Variants other than exon 55 del 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|
|2013746||NEB-Related Nemaline Myopathy, Specimen|
|2013747||NEB-Related Nemaline Myopathy, Allele 1|
|2013748||NEB-Related Nemaline Myopathy, Allele 2|
|2013749||NEB-Related Nemaline Myopathy, Interp|