While several genes have been identified as mutated in familial forms of PD, including those encoding α-synuclein, LRRK2, PINK1, Parkin, DJ-1, VPS35, and GBA1, PD is believed to arise from a complex interplay between genetic and environmental factors, altogether disrupting cellular homeostasis [3,4]. The gene discussed is LRRK2; the disease is Parkinson disease.