We present in this study a detailed mutation analysis of PRKN, PINK1, SNCA and LRRK2. We have included PD patients with a positive family history (n = 19 age at onset <50 years, n = 20 age at onset ≥ 50 years), or early-onset sporadic disease (n = 27) in order to maximize our chances of identifying mutations. The gene discussed is LRRK2; the disease is Parkinson disease.