What is amyotrophic lateral sclerosis, the root of Stephen Hawking’s death?

World renowned physicist Stephen Hawking died at the age of 76. He was diagnosed with ALS at the age of 22. — AFP

Stephen Hawking was probably the most famous man to have ALS, and I sort of understand what it is. But what does ALS stand for?

ALS stands for Amyotrophic Lateral Sclerosis. It is also called Lou Gehrig’s disease, after the famous American baseball player who had it.