Consistent with the expression level of total tau, p-Tau181 was increased in all disease groups, especially in patients with FTD, who had a nearly twofold increased expression level compared to controls (p < 0.01 by Mann–Whitney test to compare individual disease group and controls; and p < 0.01 by Kruskal–Wallis test to compare all disease groups and controls; Figure 3). This evidence concerns the gene MAPT and frontotemporal dementia.