A Mecp2 knockout (ko) mouse model, carrying a deletion of Mecp2 exons 3 and 4, showed a strong reduction in TH-expressing DN, while treatment with levodopa and a DOPA-decarboxylase inhibitor, the gold standard treatment for PD patients, markedly improved the associated behavioral abnormalities [40, 41]. The gene discussed is MECP2; the disease is Parkinson disease.