Overexpression of CK1ε at both the transcript and protein level was found in cases of sporadic ALS and AD [55, 60, 61], and elevated levels of CK1δ, TTBK1 and TTBK2 were found in the affected brain regions of AD, FTD‐Tau, FTD‐TDP‐43, and ALS cases [56, 62, 63]. Here, TTBK2 is linked to Alzheimer disease.