Heterozygous loss-of-function mutations in the TBK1 gene cause amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) (Cirulli et al, 2015; Freischmidt et al, 2015; Gijselinck et al, 2015). Here, TBK1 is linked to frontotemporal dementia.