Further, PARK2 mutations were also identified in patients with a clinical diagnosis of PSP, PD plus essential tremor (ET), as well as ET and restless legs syndrome (RLS) [Adel et al., 2006; Deng et al., 2007; Limousin et al., 2009; Pellecchia et al., 2007; Pigullo et al., 2004; Sanchez et al., 2002]. The gene discussed is PRKN; the disease is Parkinson disease.