PRKN and Parkinson disease: Although genetic research on PD has led to the identification of several monogenic forms of the disorder and numerous genetic risk factors increasing the risk of developing PD, only 5–10% of patients suffer from the monogenic form of PD, which can be caused by autosomal-dominant mutations in SNCA, LRRK2, and VPS35 and autosomal-recessive mutations in PINK1, DJ-1, and Parkin [3,4].