One study in particular found that the active form of calpain was present together with hyperphosphorylated tau in 50–75% of preparations from several human disorders, including tau pathology associated with Alzheimer's disease, Down's syndrome, diffuse Lewy body disease, progressive supranuclear palsy, and corticobasal degeneration [37]. This evidence concerns the gene MAPT and Classical progressive supranuclear palsy.