C9orf72 and amyotrophic lateral sclerosis: A hexanucleotide repeat expansion (HRE) of a noncoding GGGGCC repeat within the Chromosome 9 open reading frame 72 (C9orf72) gene has been identified as a major cause of amyotrophic lateral sclerosis (ALS, MIM: 612069) and frontotemporal lobar degeneration (FTLD, MIM: 600274) [1], [2].