iPSCs derived from patients with neurodegenerative diseases have shown key disease traits in vitro, such as amyloid-β (Aβ) accumulation in AD, tau tangles in progressive supranuclear palsy (PSP), Corticobasal Degeneration Disease (CBD), and FTD, and α-synuclein aggregation in PD. The gene discussed is MAPT; the disease is progressive supranuclear palsy.