Ketones generated from MCFA metabolism directly promote chaperone-mediated autophagy (CMA). Activation of CMA induces LRRK2 and α-synuclein degradation. Improves mitochondrial respiration by reducing glutamate- induced ROS. ROS production induced by excitotoxicity of glutaminergic neurones was observed in PD. Here, SNCA is linked to Parkinson disease.