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]. The gene discussed is MAPT; the disease is progressive supranuclear palsy.