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Genetic and Rare Diseases Information Center (GARD)

Spinal muscular atrophy


Spinal muscular atrophy is a group of inherited disorders that cause progressive muscle degeneration and weakness.[1][2] It is caused by a loss of specialized nerve cells, called motor neurons, in the spinal cord and the part of the brain that is connected to the spinal cord (the brainstem). The loss of motor neurons leads to weakness and wasting (atrophy) of muscles used for activities such as crawling, walking, sitting up, and controlling head movement. In severe cases, the muscles used for breathing and swallowing are affected.[3][4] Spinal muscular atrophy is divided into subtypes based on the severity of the disease and the age when symptoms first appear.[1][3] It is usually inherited as an autosomal recessive trait.[1]

Last updated: 4/21/2010


  1. Learning About Spinal Muscular Atrophy. National Human Genome Research Institute (NHGRI). October 19, 2009; Accessed 4/21/2010.
  2. Kaneshiro NK, Hoch DB. Spinal muscular atrophy. MedlinePlus. December 17, 2008; Accessed 4/21/2010.
  3. Spinal muscular atrophy. Genetics Home Reference (GHR). December 2009; Accessed 5/13/2011.
  4. Russman B. Spinal Muscular Atrophy. National Organization for Rare Disorders (NORD). 2008; Accessed 4/21/2010.
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Basic Information

  • Families of SMA has created a booklet entitled Understanding SMA that is intended to serve as a source of information and support for children and adults with Spinal Muscular Atrophy (SMA). 
  • Genetics Home Reference (GHR) contains information on Spinal muscular atrophy. This website is maintained by the National Library of Medicine.
  • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
  • The National Human Genome Research Institute's (NHGRI) mission encompasses a broad range of studies aimed at understanding the structure and function of the human genome and its role in health and disease. Click on the link to view the information page on this topic.
  • The National Institute of Neurological Disorders and Stroke (NINDS) collects and disseminates research information related to neurological disorders. Click on the link to view information on this topic.
  • The National Organization for Rare Disorders (NORD) is a federation of more than 130 nonprofit voluntary health organizations serving people with rare disorders. Click on the link to view information on this topic.

In Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
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