It was in 2011 when the non-coding repeat expansion in the C9orf72 gene was discovered to be the most frequent cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) [11,12]; this gene and its derived protein, C9orf72, were utterly unknown. The gene discussed is C9orf72; the disease is frontotemporal dementia.