Spinal Muscular Atrophy (SMA): Symptoms & Signs

Medically Reviewed on 9/17/2019

Spinal muscular atrophy (SMA) is a hereditary or inherited genetic disease that results in destruction of lower motor neurons, which are nerve cells in the brain stem and spinal cord that control voluntary muscle activity. There are three types of spinal muscular atrophy that vary by severity and age of onset of symptoms.

Signs and symptoms of SMA depend upon the exact type of the condition that is present. Associated symptoms can include problems with any type of movement. Examples of symptoms and signs include

  • muscle weakness,
  • breathing problems,
  • limited mobility,
  • decreased muscle tone,
  • eating problems,
  • swallowing problems,
  • delayed gross motor skills,
  • scoliosis (an abnormal bending of the spine), and
  • spontaneous tongue movements.

Cause of spinal muscular atrophy (SMA)

Mutations (defects) in a gene known as SMN1 cause spinal muscular atrophy.

Other spinal muscular atrophy (sma) symptoms and signs

  • Breathing Problems
  • Decreased Muscle Tone
  • Delayed Gross Motor Skills
  • Eating Problems
  • Limited Mobility
  • Muscle Weakness
  • Scoliosis
  • Spontaneous Tongue Movements
  • Swallowing Problems

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Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.