What is the prognosis of spinal muscle atrophy (SMA)?

Updated: Nov 05, 2018
  • Author: Ashish S Ranade, MBBS, MS, MRCS; Chief Editor: Jeffrey A Goldstein, MD  more...
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As a general rule, the younger the patient at disease onset, the worse the prognosis. The overall median age at death exceeds 10 years. Intelligence is unaffected by SMA. Patients with type I SMA usually die by age 2 years. Patients with type II SMA have a greater expected life span than patients with type I SMA. Some patients with type II SMA live into the fifth decade of life. Patients with type III SMA have nearly normal life expectancy.

Death occurs as a result of respiratory compromise. The life span of affected individuals has significantly increased with the use of intermittent positive-pressure ventilation, with or without a tracheostomy.

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