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Spinal muscular atrophy type 2

Other Names for this Disease
  • Muscular atrophy, spinal, infantile chronic form
  • Muscular atrophy, spinal, intermediate type
  • SMA2
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Spinal muscular atrophy type 2 (SMA II) is part of a group of disorders that affect the control of muscle movements. 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. SMA II is characterized by muscle weakness that develops in children between ages 6 and 12 months. Children with SMA II can sit without support, although they cannot stand or walk unaided.[1] Finger trembling and general weakness are common. It is typically caused by mutations in the SMN1 gene and is inherited in an autosomal recessive manner.[2]
Last updated: 11/28/2011


  1. Spinal muscular atrophy. Genetics Home Reference (GHR). December 2009; Accessed 5/13/2011.
  2. Thomas W Prior, Barry S Russman. Spinal Muscular Atrophy. GeneReviews. January 27, 2011; Accessed 11/28/2011.
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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 type 2. This website is maintained by the National Library of Medicine.
  • 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.

In Depth Information

  • The Online Mendelian Inheritance in Man (OMIM) is an catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs.  Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Spinal muscular atrophy type 2. Click on the link to view a sample search on this topic.