C9orf72 and amyotrophic lateral sclerosis: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that affects both upper and lower motor neurons, which originate from the brain and spinal cord, respectively [1] The two types of ALS with respect to the cause are familial ALS and sporadic ALS; the latter is linked to mutations in several genes, such as superoxide dismutase 1 (SOD1), fused in sarcoma (FUS), TAR DNA-binding protein (TDP), and chromosome 9 open reading frame 72 (C9ORF72) [2, 3].