Although most cases are idiopathic, approximately 10% of PD cases are familial, and more than 20 causative genes with high penetrance have been identified including synuclein alpha (SNCA), parkin RBR E3 ubiquitin protein ligase (PRKN), and leucine rich repeat kinase 2 (LRRK2).3–6. The gene discussed is PRKN; the disease is Parkinson disease.