C9orf72 and amyotrophic lateral sclerosis: Expansion of non-coding repeat elements within the human genome have been identified to cause more than 30 human diseases to date [8], including fragile X tremor ataxia syndrome (MIM #300623), myotonic dystrophy types 1 and 2 (MIM #160900 and #602668) and C9orf72-associated amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (MIM #105550) [8].