Through the comparison study for several biomarkers, we found the plasma p-tau217 was the most effective biomarker in AD diagnosis, and p-tau217, p-tau231 and p-tau181 showed the best performance for differential diagnosis of AD from PSP, FTD and DLB respectively, GFAP presented the most significant correlations with AD pathology, and gray matter volume reduction of frontal and temporal lobe. The gene discussed is GFAP; the disease is frontotemporal dementia.