Mutations in key genes of the endosomal/lysosomal system such as leucine-rich repeat kinase 2 (LRRK2), glucocerebrosidase (GBA), and adenosine three phosphates (ATP) are associated with an increased risk of PD by increasing α-synuclein protein accumulation and Lewy bodies formation [7]. The gene discussed is LRRK2; the disease is Parkinson disease.