Missense mutations in the gene encoding leucine-rich repeat kinase 2 (LRRK2) are the most common genetic cause of familial forms of Parkinson’s disease (PD), while non-coding sequence variations in the LRRK2 locus have been linked in genome-wide association studies to the more common sporadic form of the disease [1,2]. The gene discussed is LRRK2; the disease is Parkinson disease.