Of note, TauC3, a truncated form of tau generated by caspase-3 cleavage at D421 and a precursor of bioactive seeds [27], was present only in PSP-tau seeded Variant 4 but not in AD-tau seeded Variant 4 (Fig. 3b). The gene discussed is CASP3; the disease is supranuclear palsy, progressive, 1.