ALS (amyotrophic lateral sclerosis) is a progressive neurological disease that affects the nerve cells controlling voluntary muscle movements. The exact cause of ALS is not fully known, but it is generally understood that ALS is not contagious and cannot be caught from another person. Instead, ALS arises through a combination of genetic and environmental factors. Key ways one may "get" ALS include:
- Genetics: About 5-10% of ALS cases are inherited due to gene mutations passed down from parents, such as defects in the SOD1 or C9ORF72 genes. Having a family history of ALS slightly increases the risk but is not a certainty.
- Environmental exposures: Exposure to toxins such as heavy metals, solvents, pesticides, radiation, and certain chemicals (including those sometimes encountered by military personnel) may increase the risk.
- Physical injuries: Head injuries or concussions, especially repeated or severe traumatic brain injury, have been associated with higher ALS risk.
- Other factors: Smoking tobacco products is another environmental risk factor thought to increase ALS risk.
- Age and demographics: ALS most commonly develops between ages 55-75 and is slightly more common in males and non-Hispanic White people.
In summary, ALS develops due to a combination of genetic predisposition and environmental exposures rather than through contagion or infection. Most cases occur sporadically without a clear inherited cause.
