USP30 and Parkinson disease: Loss-of-function mutations in PINK1and PRKN genes lead to a buildup of defective mitochondria and a gradualloss of dopaminergic neurons in the basal ganglia, resulting in arare and inherited form of early onset Parkinsonism.15,16 Inhibiting USP30 may therefore boost a mitochondrial turnover inboth early onset Parkinsonism and in PD, at least in this populationof patients, offering a new strategy for the treatment of the diseaseand similar neurodegenerative conditions.