TTBK1 and frontotemporal dementia: Indeed, such a misregulated kinase expression has been reported for CK1ε, overexpressed both at the transcript and protein level in ALS and AD cases [55, 60, 61], and CK1δ, TTBK1, and TTBK2 at the protein level in AD, FTD and ALS cases [56, 62, 63].