MAPT and tauopathy: Indeed, in a post-mortem series of 9 IgLON5-Ab disease patients, tau pathology was not detected in three with short disease duration, while two patients had a prominent antibody deposition (mostly IgG4) in the predilected area of tau deposition (brainstem, olivary nuclei, and cerebellar cortex), indicating that IgLON5-Ab deposition precedes the tauopathy [47].