Spinal Muscular Atrophy Diagnostic Assay, Deletion/Duplication Analysis, Varies
Use
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder characterized by motor neuron degeneration leading to muscular atrophy with progressive paralysis. The test is useful for first-tier newborn screening for SMA, prenatal testing for SMA, and diagnostic testing to confirm a suspected diagnosis of SMA. The test determines SMN1 exon 7 copy number and SMN2 exon 7 copy number and ascertains whether the g.27134T>G alteration is present or absent in patients found to have 2 copies of SMN1. The presence of this alteration is linked to being a '2+0' carrier in specific populations and can influence clinical decisions.
Special Instructions
Prenatal specimens require consultation with the laboratory. A maternal blood specimen is mandatory for prenatal testing, with separate charges for additional cultures and maternal cell contamination studies. The test has been developed and its performance characteristics determined by Mayo Clinic in compliance with CLIA requirements; it has not been FDA cleared or approved.
Limitations
Point alterations are undetectable by this assay. It cannot definitively discriminate between 2 copies of SMN1 on the same chromosome versus on separate chromosomes for most ancestries. Rare alterations may lead to false-negative or false-positive results. Results should be interpreted in conjunction with clinical findings, family history, and other laboratory data, as errors in interpretation may occur if incomplete or inaccurate information is provided.
New York Approved
Methodology
PCR-based (ddPCR)
Biomarkers
LOINC Codes
- 49857-6
- 50397-9
- 49857-6
- 69047-9
- 48767-8
- 31208-2
- 18771-6
Result Turnaround Time
5-10 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
3 mL
Minimum Volume
Not provided
Container
Lavender top (EDTA) or yellow top (ACD)
Collection Instructions
Invert several times to mix blood. Send whole blood specimen in original tube. Do not aliquot. Whole blood collected postnatal from an umbilical cord is also acceptable.
Patient Preparation
A previous hematopoietic stem cell transplant from an allogenic donor will interfere with testing.
Storage Instructions
Send ambient, preferred within 4 days of collection.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 4 days |
| Refrigerated | 4 days |
| Frozen | 4 days |