What Causes ALS?

Unfortunately, no one knows what causes ALS (amyotrophic lateral sclerosis). While much is known about how it affects the nervous system, its symptoms, progression and prognosis, scientists and doctors have failed to pinpoint an underlying cause. Not only is the cause of ALS unknown, but the risk factors that predict who is most likely to be affected are unknown as well.

Some clues to the underlying causes of ALS have been found. For one, some cases appear to run in families, known as familial ALS, suggesting that genetics may play at least a partial role in the disease. In these families, mutations in a gene called SOD1 have been found. This gene is normally important for preventing free radical damage to cells in the body. How this mutation leads specifically to ALS and damage to motor neurons in the nervous system is not understood.

Several other factors have been investigated by various scientists but none have lead to definitive answers regarding the cause of ALS. For example, it has been hypothesized that autoimmunity and/or environmental exposure to toxins or infectious agents may lead to the disease. However, none of these has been confirmed.

Ongoing research may eventually show which factors are most related to ALS, but for now it is a mystery which has not been solved.