SMA Diagnostics

How does the diagnostics for 5q-Spinal Muscular Atrophy (SMA) work?

Testing Algorithm for 5q-Spinal Muscular Atrophy

Our service is ideal for identification of SMA in at-risk patients showing specific clinical symptoms or for an individual or family member who has a family history of SMA.

We provide a SMA Sampling Kit which includes:

  • Dried Blood Spot card (DBS)
  • Informed Consent Form (ICF)
  • Envelope for the return of the Sampling Kit (including ICF and DBS card) to ARCHIMEDlife Laboratories
  • Instructions for Blood Sampling and Shipment

After sample collection is complete, please return the Sampling Kit (including the DBS card and ICF) to ARCHIMEDlife Medical Laboratories using the shipping instructions provided. Diagnostic results will be available within a few working days.

The diagnostic algorithm

How results are reported

Primary diagnostics for 5q-SMA involves the determination of SMN1 gene copy number in adults or infants suspected of 5q-SMA. Our diagnostics can result in one of three possible findings.

Medical report 1

Result: No SMN1 gene copy was determined.

Interpretation: Spinal Muscular Atrophy (SMA) is confirmed.

ARCHIMEDlife laboratory will proceed with SMN2 copy number analysis. 

Medical report 2

Result: One SMN1 gene copy was determined.
ARCHIMEDlife laboratory will proceed with sequence analysis.

(a) SMN1 mutation was detected.

Interpretation: Spinal muscular atrophy (SMA) is confirmed.
Our laboratory proceeds with SMN2 copy number analysis (see Step 2). A dried blood spots (DBS) card of family members may be required for confirmatory testing.


(b) No SMN1 mutation was detected.

Interpretation: Carrier status of spinal muscular atrophy (SMA) is confirmed. The affected infant/adult has one normal copy of SMN1 gene.

Medical report 3

Result: Two or more SMN1 gene copies were determined.
Interpretation: 5q-spinal muscular atrophy (SMA) could not be confirmed. Please consider other diseases.