MAPT and rheumatic disorder: Both of these disorders are associated with abnormal deposition of tau proteins in different parts of the brain, and are both referred to as “tauopathies.”20,48 Just as damaged and aggregated proteins may be targeted by autoantibodies, it can be hypothesized that misfolded tau proteins may be a substrate for autoantigens in patients with rheumatic diseases, and may account for overlapping features of CBS and PSP seen in rheumatic diseases.