Why Do People Develop ALS?

ALS, or Amyotrophic Lateral Sclerosis, is a progressive neurodegenerative disease that affects the central nervous system. The exact causes of ALS are not fully understood, and there is currently no known cure. While researchers have not yet pinpointed exactly who is most at risk for developing the condition, studies have shown that around 5% to 10% of cases are linked to family history and genetic inheritance. This type is referred to as familial ALS (FALS). In contrast, 90% to 95% of cases have no clearly identifiable cause and are classified as sporadic ALS (SALS).

Genetic Factors in ALS

Recent research suggests that even sporadic ALS may have a genetic component. Individuals who have a sibling with sporadic ALS face a 0.5% risk of developing the disease themselves. For offspring of someone with SALS, the risk increases to about 1%. By the age of 85, individuals with a family history of ALS are several times more likely to develop the condition compared to the general population.

Environmental and Biological Triggers

Besides genetics, many experts believe that sporadic ALS could be influenced by a range of biological and environmental factors. These include neuroinflammatory responses, oxidative stress caused by free radicals, excitotoxicity from excessive glutamate, and deficiencies in neurotrophic factors that support nerve cell survival.

Cellular and Molecular Mechanisms

Additional contributing factors may include the accumulation of abnormal proteins, disruptions in apoptosis (programmed cell death), calcium overload, mitochondrial dysfunction, impaired axonal transport, and exposure to toxins or certain viruses. Environmental factors and previous physical trauma are also being studied for their potential roles in triggering ALS onset.