One major challenge is to now develop analytical methodologies to accurately categorize patients according to the molecular structure of the underlying pathological tau protein assemblies to achieve more accurate diagnosis, prognosis, and effective clinical therapies for the wide spectrum of brain diseases involving misfolded tau and other neuronal-enriched fibrillar proteins such as α-synuclein (Carlson and Prusiner, 2021; Thomzig et al., 2021). The gene discussed is MAPT; the disease is brain disorder.