What are the types of spinal muscle atrophy (SMA)?

Updated: Nov 05, 2018
  • Author: Ashish S Ranade, MBBS, MS, MRCS; Chief Editor: Jeffrey A Goldstein, MD  more...
  • Print
Answer

SMA is commonly divided into four types on the basis of the patient's age at onset and the highest physical milestone achieved, as follows:

  • Type I (Werdnig-Hoffmann disease) - Onset between birth and age 6 months
  • Type II - Onset between the ages of 6 and 12 months
  • Type III (Kugelberg-Welander disease) - Onset between the ages of 2 and 15 years
  • Type IV - Adult onset

Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!