The project focuses on C9orf72, the most frequent genetic form of frontotemporal dementias (FTD, or frontotemporal lobar degeneration, FTLD) and amyotrophic lateral sclerosis (ALS). FTD is the second commonest cause of degenerative dementia in presenium after Alzheimer's disease. Behavioural and cognitive impairments progressively lead to dementia. ALS produces progressive muscle weakness leading to the death in 2 to 4 years. Since 2006, major discoveries have linked FTLD and ALS: