We analyzed TMEM59 levels in the brains of AD patients and the tauP301S transgenic (PS19) mice, evaluated behaviors and tauopathy‐related pathologies in PS19 mice with TMEM59 haploinsufficiency, and studied the regulation of TMEM59 on chaperone‐mediated autophagy (CMA) using biochemical analysis. The gene discussed is TMEM59; the disease is tauopathy.