MAPT and Alzheimer disease: PSEN1 p.L226R was found in an early‐onset AD (EOAD) family characterized by language impairment at disease onset, a novel probably pathogenetic variant (p.D534H) was identified in a frontal‐temporal dementia gene, TANK‐binding kinase 1 (TBK1) with a typical AD phenotype in a late‐onset AD (LOAD) family, and a PSEN2p.H169N mutation and two benign MAPT (p.Q230R and p.V48L) mutations were detected in three EOAD patients.