MAPT and neuropathy, small fiber: More than 70% of peripheral neurons are small-fiber neurons (un-myelinated), and the estimation of intra-epidermal nerve-fiber density is the gold standard for the diagnosis of small-fiber neuropathy (Akihiko et al., 2021) Multiple ongoing research studies are underway in order to determine the role of tau protein as a potential biomarker to diagnose these disabling neuro-degenerative diseases at earlier stages and to compare it to imaging techniques.