The loss of parvalbumin-positive (PV+) neurons in the substantia nigra pars reticulata (SNR) was observed in patients with end-stage Parkinson’s disease (PD) and our previously constructed old-aged Pitx3-A53Tα-Syn × Tau–/– triple transgenic mice model of PD. The gene discussed is PITX3; the disease is Parkinson disease.