CA2 has also garnered attention, with notable accumulation of abnormal proteins in Lewy body disease (LBD),11 prion diseases,12 chronic traumatic encephalopathy (CTE),13 and primary age‐related tauopathy (PART),14 along with four‐repeat tauopathies like progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and argyrophilic grain disease (AGD).15 Here, CA2 is linked to argyrophilic grain disease.