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Genetic and Rare Diseases Information Center (GARD)

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Amyotrophic lateral sclerosis

Other Names for this Disease
  • ALS
  • ALS1
  • Amyotrophic lateral sclerosis type 1
  • Lou Gehrig disease
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What causes amyotrophic lateral sclerosis?

In approximately 90-95% of cases the cause of amyotrophic lateral sclerosis (ALS) is unknown and is sporadic (occurring in individuals with no history of the condition in the family).[1]

The remaining 5-10% of cases are genetic (familial), often occurring in individuals with a family history of the condition. Mutations in any of several genes, including the C9orf72, SOD1, TARDBP, FUS, ANG, ALS2, SETX, and VAPB genes, can cause familial ALS and may contribute to the development of sporadic ALS. About 60% of individuals with familial ALS have an identifiable genetic mutation; the genetic cause in the remaining cases is unknown.[1] The genes associated with ALS appear to play a role in how neurons function or are involved in regulating the production of various proteins.[1]

Over the years, various types of environmental exposures have been proposed as possible contributors to the cause of ALS, including mercury, manganese, products used in farming (fertilizers, insecticides, herbicides), and physical and dietary factors. Exposures have been suggested as a possible explanation for the increased incidence of ALS in Gulf War veterans. Further investigation is ongoing.[2]
Last updated: 1/11/2013

  1. Amyotrophic lateral sclerosis. Genetics Home Reference. August 2012; Accessed 1/7/2013.
  2. Lisa Kinsley and Teepu Siddique. Amyotrophic Lateral Sclerosis Overview. GeneReviews. May 31, 2012; Accessed 1/11/2013.
  3. Lisa Dellefave, MS, CGC . Amyotrophic Lateral Sclerosis Overview. Genetic Reviews. Accessed 10/9/2007.