Risk factors of ALS

No clear risk factors are associated with most cases of ALS (Lou Gehrig's disease). Risks factors are not associated with any genetic type, crossing all races and ethnic backgrounds. Although ALS commonly strikes people between 40-70 years old, it also affects both younger and older. However, men are affected more often than women.

In 90-95% of cases, the disease occurs apparently at random. This is called Sporadic ALS (SALS).

Familial ALS (FALS), which only accounts for 5-10% of the cases in the United States, is inherited from a family member. Only one parent is required to carry the gene. Some FALS cases are linked to a genetic defect on chromosome 21 (see Causes of ALS). This particular mutation only accounts for approximately 20% of all FALS cases (or 1-2% of all ALS cases). This means that other unidentified genetic causes exist.