Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to amyotrophic lateral sclerosis ?
    ### Response:
    Mutations in several genes can cause familial ALS and contribute to the development of sporadic ALS. Mutations in the C9orf72 gene account for 30 to 40 percent of familial ALS in the United States and Europe. Worldwide, SOD1 gene mutations cause 15 to 20 percent of familial ALS, and TARDBP and FUS gene mutations each account for about 5 percent of cases.
    