Test Overview
Test Methodology

MLPA probes hybridize to target regions of SMN1 and SMN2 genes and are amplified by multiplex PCR. The amplification products are analyzed by capillary electrophoresis and SMN1 and SMN2 copy numbers are generated.

Test Usage

Detection of the copy number (deletions/duplications) of the SMN1 and SMN2 genes in patients with a clinical diagnosis of Spinal Muscular Atrophy.

Reference Range *

Interpretive report provided.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Limitations

This assay will not detect point mutations or frame-shift mutations in SMN1 or SMN2 genes.

Test Details
Days Set Up
Various days Monday – Friday
Analytic Time

10 days

Soft Order Code
SMN1D
MiChart Code
Spinal Muscular Atrophy Deletion
Synonyms
  • Spinal Muscular Atrophy Types I, II, III
  • Survival Motor Neuron 1
  • Infantile Muscular Atrophy
  • Werdnig-Hoffmann Disease
Laboratory
MMGL
Section
MMGL Molecular Genetics
Specimen Requirements
Collection Instructions

Collect blood specimen in a EDTA lavender top tube. Send it within 24 hours if stored at room temperature or within 5 days if stored refrigerated.

Fill out a MLabs Molecular test requisition (or place an e-order if applicable):
https://mlabs.umich.edu/media/166
Fill out a Clinical History Form for Insurance Prior Authorization (include all required documentation indicated at the bottom of this form):
https://mlabs.umich.edu/sites/default/files/2020-08/file/mlab11618clini…
Fill out a UMHS Request and Consent for Genetic Testing form:
https://mlabs.umich.edu/sites/default/files/2023-04/file/germline-conse…
Michigan State law requires the ordering provider to obtaining informed consent from the patient prior to prognostic or predictive genetic testing. Contact a MLabs Client Services Center at 800-862-7284 to request paper copies or to setup a client account.

Alternate Specimen
Cheek swab kit (Oragene OCD-100), follow collection instructions.
Saliva kit (Oragene OGD-510), follow collection instructions.
Normal Volume
5 mL whole blood
Minimum Volume
1 mL whole blood (0.5 mL infants)
Storage Temperature
Room temperature up to 24 hours or 2-8°C up to 5 days for blood
2-36°C for saliva
Rejection Criteria
Hemolyzed blood sample. Fresh tissue (POC) or paraffin embedded specimens are not acceptable.
Additional Information

Spinal Muscular Atrophy (SMA) is an autosomal recessive neuromuscular disorder. SMN1 and SMN2 are two highly-similar genes that have a critical role in defining SMA. SMN2 is much less efficient in making the SMN protein; therefore it is the SMN1 gene which is the determinant factor in SMA. Most patients with SMA are homozygous for a deletion or gene conversion of SMN1. The presence of multiple copies of SMN2 in patients homozygous for a deletion or gene conversion of SNM1 can modify the phenotype and lead to less severe disease.

Most insurance carriers require prior authorization for genetic testing. Testing will not begin until insurance prior authorization is received by the laboratory or it is confirmed that prior authorization is not required. The ordering health care provider can obtain the prior authorization or request the laboratory to submit it. To obtain BCN prior authorization call Joint Venture Hospital Laboratories (JVHL) at 800-445-4979; for all other insurances, contact the plan directly. By ordering this test the clinician acknowledges that informed consent, https://mlabs.umich.edu/sites/default/files/2023-04/file/germline-conse…, has been obtained from the patient as required by applicable state or federal laws and the ordering clinician has authorization from the patient permitting MLabs to report the test results to the ordering clinician. Test includes medical geneticist interpretation of results billed as a separate additional charge. This test is not available without interpretation.

Billing
CPT Code
81329
Fee Code
DA157
Pro Fee CPT
G0452-26
NY State Approved
No