It is now evident that mutations in PARKIN are associated with early development of motor symptoms, hyperreflexia, bradykinesia, dystonia, tremor, good response to low dose of l-DOPA at onset, and later l-DOPA-induced dyskinesia, as well as slow progression of psychiatric symptoms, with any clinical evidence of dementia (Ishikawa and Tsuji 1996; Ebba; Lohmann et al. 2003, 2009). The gene discussed is PRKN; the disease is drug-induced dyskinesia.