LRRK2 and Parkinson disease: SIRT1 activity is also decreased in induced pluripotent stem cell (iPSC)-derived dopaminergic neurons carrying a glycine to serine mutation (G2019S) in leucine-rich repeat kinase 2 (LRRK2), which is causally associated with PD and is involved in the impairment of mitochondrial function (Schwab et al., 2017).