Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Amyotrophic lateral sclerosis ?
    ### Response:
    Amyotrophic lateral sclerosis (ALS), also referred to as "Lou Gehrig's disease," is a progressive motor neuron disease which leads to problems with muscle control and movement. There are various types of ALS, which are distinguished by their signs and symptoms and their cause.
    