Rab12 has recently gained attention as one of the physiological substrates of the Leucine-Rich Repeat kinase 2 (LRRK2) (27), a kinase whose increased activity occurs in idiopathic Parkinson’s disease (PD) and mutations leading to increased kinase activity comprise the most common cause of familial PD (28). The gene discussed is LRRK2; the disease is Parkinson disease.