What exactly is amyotrophic lateral sclerosis?

Lou Gehrig's disease: Als is a disease affecting the nerve cell body, causes weakness, muscle wasting, and fasciculations or fluttering of the muscles. It can affect mobility, swallowing, and breathing. There is no known cure to date, and the prognosis is often very poor. We believe it is a disorder of "misfolded proteins", similar in some ways to alzheimer's and parkinson's, but a far rarer condition, fortunately.