Even though a single set of two conformations of insoluble tau fibrils in AD have been identified by cryo-EM which are distinguished from tau fibrillar structures present in other tauopathies [23, 24], the presence of soluble forms of misfolded tau with high seeding activity can be monitored with another set of experimental approaches [17, 21, 26, 90, 91]. The gene discussed is MAPT; the disease is Alzheimer disease.