EM has shown that tau fibrils generally have a structured core surrounded by an unstructured region called the fuzzy coat for its fuzzy appearance by EM that contains the unstructured regions of the tau protein, PTMs of tau, and sometimes other proteins and cofactors that may associate with tau fibrils (77).EM has also shown that for many tauopathies the fibrils are formed by two tau molecules coming together, then stacking in pairs to form long, twisted fibrils made of two distinct filaments (77). This evidence concerns the gene MAPT and tauopathy.