How is spinal muscular atrophy (SMA) diagnosed?

Spinal muscular atrophy is usually diagnosed through a blood test to check for the presence of the SMN1 gene (genetic testing). This gene will be missing in about 95 percent of those with SMN-related SMA. In the other 5 percent, the gene will appear mutated. Your doctor will order this test if he or she suspects that your child might have SMA based on his or her symptoms and other diagnostic work up. Your doctor may order an electrical study called EMG (electromyography) or perform a muscle biopsy to confirm the diagnosis of SMA.

Last reviewed by a Cleveland Clinic medical professional on 11/24/2015.


  • Darras BT, Markowitz JA, Monani UR, De Vivo DC. Spinal muscular atrophies. In: Darras BT, Jones HR, et al, editors. Neuromuscular Disorders of Infancy, Childhood, and Adolescence. 2nd ed. Amsterdam: Academic Press, an imprint of Elsevier; 2014: Chap 8.
  • Amato AA, Russell JA. Spinal Muscular Atrophies. In: Amato AA, Russell JA. eds. Neuromuscular Disorders, 2e. New York, NY: McGraw-Hill; 2015.
  • Genetics Home Reference. Spinal muscular atrophy Accessed 11/24/2015.
  • National Human Genome Research Institute. Learning About Spinal Muscular Atrophy Accessed 11/24/2015.
  • Muscular Dystrophy Association (MDA). Spinal muscular atrophy Accessed 11/24/2015.

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