Scientific BackgroundLRRK2 is a member of the leucine-rich repeat kinase family. It role is yet unknown but it may play a role in the phoshorylation of proteins central to parkinson diseases. LRRK2 contains an ankryin repeat region, a leucine-rich repeat (LRR) domain, a kinase domain, a DFG-like motif, a RAS domain, a GTPase domain, a mLK-like domain and a WD40 domain. LRRK2 is present in the cytoplasm but also associates with the mitochondrial outer membrane. Defects in LRRK2 are the cause of Parkinson disease 8 (PARK8). Parkinson disease is characterised by bradykinesia, resting tremor, muscular rigidity and postural instability, as well as by a clinically significant response to treatment with levodopa. The pathology involves the loss of dopaminergic neurons in the substantia nigra and the presence of Lewy bodies (intraneuronal accumulations of aggregated proteins), in surviving neurons in various areas of the brain. PARK8 is an autosomal-dominant late-onset parkinsonism, characterized by onset from 50 to 65 years, with slow progression and relatively benign course.