LRRK2 and Parkinson disease: (1) healthy, (2) preclinical LRRK2 PD (LRRK2- mutation- carriers without clinical symptoms), (3) prodromal LRRK2 PD (LRRK2 mutation carriers with presence of early symptoms and signs before PD diagnosis is possible), (4) clinical LRRK2 PD (LRRK 2 carriers with diagnosis of PD based on the presence of classical motor signs) and (5) clinical PD (idiopathic PD).