Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease or motor neuron disease, is a progressive neurological disease that causes the neurons that control voluntary muscles (motor neurons) to degenerate, according to the National Institutes of Health (NIH).
The term “Lou Gehrig’s disease” is named for the famed American baseball player who developed ALS in 1939 at age 36. In the United States, as many as 20,000 to 30,000 people have the disease, and about 5,000 people are diagnosed with it each year, according to the Centers for Disease Control and Prevention (CDC).
ALS commonly strikes people 40 to 60 years old. It affects people of all races and ethnicities. The disease is slightly more common in men than in women, but the difference is decreasing.