However, the onset of fewer familial forms of PD (FPD) can be induced by mutations or variations of a dozen or more genes, including α-synuclein (α-syn) [5], Parkin [6], PINK1 [7], DJ-1 [8], FBXO7 [9], CHCHD2 [10] and LRRK2 [11]. The gene discussed is PRKN; the disease is Parkinson disease.