In the last decade numerous studies aimed to uncover the role of repeat expansions other than C9orf72 in ALS, such as NIPA1, ATXN1 and ATXN2. Repeat expansions of these genes were primarily associated with other neurodegenerative conditions such as spinocerebellar ataxias and hereditary spastic paraplegia [6–8]. Here, C9orf72 is linked to amyotrophic lateral sclerosis.