Spinal muscular atrophy (SMA), carrier testing

Alphabetical Test listing

Spinal muscular atrophy (SMA), carrier testing-13550

Spinal muscular atrophy (SMA), carrier testing
Dubowitz disease (SMA type II)
Kugelberg-Welander disease (SMA type III)
Prenatal SMA
Werdnig-Hoffman disease (SMA type I)
  • Carrier testing for individuals in the general population, or individuals with a family history of SMA, or couples who are planning a pregnancy or who are already pregnant.
  • Prenatal diagnosis for at-risk pregnancies, when both parents are carriers or when severe joint contractures are found on fetal ultrasound.
ACD-A whole blood

Yellow ACD-A



10 mL

In some circumstances, specimens from other family members may be required.


Yellow ACD-A

EDTA whole blood

Lavender (EDTA), 10mL


Ambient (preferred) - 2 days

  • Frozen specimen
  • Hemolysis
  • Quantity not sufficient for analysis
  • Improper container
  • Blood specimens more than four days post draw
  • Yellow-top (ACD-B) tubes are not acceptable
Esoterix Genetic Laboratories (516) via LabCorp (450010): R-LC
Mo - Sa
9 - 10 days

After DNA is isolated, exon 7 of the SMN1 gene and internal standard reference genes are amplified by real-time polymerase chain reaction(PCR). A mathematical algorithm calculates SMN1 copy numbers of 0, 1, 2 or 3 with statistical confidence. To rule out the presence of sequence variants that could interfere with analysis and interpretation, sequence analysis of primer and probe binding sites is performed for samples with one copy of SMN1. Reflex testing to SMN2 copy number analysis is performed for specimens with 0 copies of SMN1.


An interpretive report will be provided