Individuals diagnosed with ALS, who are confirmed to carry the Chromosome 9 Open Reading Frame 72 (C9ORF72) gene mutation by CLIA-certified lab results, are eligible for enrollment. Researchers want to understand the natural history of C9ORF72 related ALS in terms of measures of rate of progression as well as understanding how the size of the hexanucleotide repeat expansion influences disease parameters. The investigators hope that the intense study of patients with the C9ORF72 mutation will ultimately help us develop treatments for this common form of ALS.