Syndecan‐1 and −4 are unlikely to be major players in inter‐neuronal tau spread because of their restricted localisation; syndecan‐1 is mainly expressed in cerebellar granule neurons, which are largely spared in tauopathies, with the exception of PSP (Braak, Braak, Bohl, & Lang, 1989; Irwin, 2016) and syndecan‐ 4 mainly localises in glial cells (Hsueh & Sheng, 1999). This evidence concerns the gene MAPT and tauopathy.