Commonly called Lou Gehrig's disease, amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that kills nerve cells, robbing its victims of the ability to control their muscles. The disease strikes otherwise healthy adults, destroying their ability to walk, talk and eventually, to breathe.The disease is always fatal, claiming 80% of its victims within five years. Its most famous victim gave not only his life, but also his name to it.