Rasagiline, a selective and irreversible inhibitor of monoamine oxidase B [7, 8], has been shown to be efficacious at relieving the symptoms of PD and is well-tolerated when administered as monotherapy, or as an adjunct to levodopa, in Japanese patients with PD in two randomized, double-blind, placebo-controlled, 26-week studies [9, 10]. The gene discussed is MAOB; the disease is Parkinson disease.