Tau usually with multiple post-translational modifications (PTM) including phosphorylation, acetylation, disulfide bond, N-linked or O-linked glycosylation, isopeptide bond, methylation, and ubiquitination conjugation, and these PTMs as well as tau aggregation are closely related to its function and Alzheimer’s disease (AD). The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.