Prenatal Spinal Muscular Atrophy (SMA) Test
Use
This prenatal test is intended to detect spinal muscular atrophy (SMA) during the prenatal period by analyzing the SMN1 gene, which accounts for approximately 95% of SMA cases. SMA is an autosomal recessive condition characterized by progressive muscle weakness and can present prenatally with severe phenotypes including fetal akinesia or arthrogryposis; early genetic diagnosis facilitates family planning, potential early interventions, and accurate recurrence risk assessment. The clinical interpretation is supported by GeneDx’s extensive rare-disease exome dataset and expertise in prenatal sequencing.
Special Instructions
Order via the GeneDx prenatal test requisition form. Sample types accepted include amniotic fluid, cultured amniocytes, cultured chorionic villi (CVS), products of conception (POC), and extracted DNA. Maternal sample (blood or buccal) is required for maternal cell contamination (MCC) analysis. A paternal sample may also be needed if trio exome context is utilized. Specimens should meet GeneDx DNA handling and labeling requirements outlined on their specimen requirements site.
Limitations
Results may be limited by maternal cell contamination, low DNA quality, or insufficient sample. FFPE-derived DNA is not accepted. The test may not detect rare complex variants not captured by NGS-based screening such as deep intronic variants or low-level mosaicism. Negative results do not fully exclude SMA if clinical suspicion remains high.
Methodology
NGS (Targeted)
Biomarkers
Result Turnaround Time
14-21 days
Related Documents
For more information, please review the documents below
Specimen
Amniotic Fluid
Volume
Not provided
Minimum Volume
Not provided
Other tests from different labs that may be relevant