Testing and Diagnosis

Spinal Muscular Atrophy Testing and Diagnosis

Spinal muscular atrophy (SMA) is usually diagnosed through a blood test to check for the presence of the SMN1 gene (genetic testing). This gene is missing in about 95 percent of those with SMN-related SMA. In the other 5 percent, the gene will appear mutated.

Your physician will order this test if they suspect that you or your child might have SMA based on symptoms and other diagnostic work-up. They may order an electrical study called EMG (electromyography) or perform a muscle biopsy to confirm the diagnosis of SMA.

SMA is diagnosed after symptoms start and testing is done. Early signs of muscle weakness may point to the disease, but only testing can confirm the diagnosis.