Amyotrophic lateral sclerosis is a disease.
Amyotrophic lateral sclerosis ( ALS ) , also known as Lou Gehrig 's disease and motor neurone disease ( MND ) , is a specific disease that causes the death of neurons which control voluntary muscles . The disease usually starts around the age of 60 and in inherited cases around the age of 50 . In Europe and the United States the disease affects about two people per 100,000 per year . Descriptions of the disease date back to at least 1824 by Charles Bell . A motor neuron disease ( MND ) is any of several neurological disorders that selectively affect motor neurons , the cells that control voluntary muscles of the body .