TBK1 and frontotemporal dementia: The pathomechanism underlying TBK1-associated ALS/FTD most likely results from TBK1 loss-of-function as most TBK1 mutations are either deletions that cause haploinsufficiency or nonsense and frameshift mutations that either negatively impact its function and kinase activity or result in nonsense-mediated mRNA decay and reduced expression of the kinase [130,131,133-135].