C9orf72 and amyotrophic lateral sclerosis: The same approach can be applied to other aggregation-prone proteins involved in ALS-FTD, such as ataxin 2, TIA-1, C9orf72 dipeptide repeats, and FUS, although it will be important to maintain adequate expression levels of the wild-type proteins that exert essential physiological functions [354,355,356,357].