MAPT and argyrophilic grain disease: Then, after performing univariate and multivariate analyses to assess the effects of factors on the development of GFAs by region in all cases, we examined the immunohistochemical features of GFAs in AGD cases using phosphorylation‐ or conformational change‐specific anti‐tau, anti‐ubiquitin and anti‐p62 antibodies as well as the Gallyas method.