Most of the knowledge about the pharmacogenomics of PD drugs deals with genes involved in dopaminergic activity, especially dopamine receptors (DRD1, DRD2, DRD3), transporters (DAT, SLC22A1/OCT1) and enzymes responsible for dopamine transformation and degradation (COMT, MAO-B, DDC) (14). The gene discussed is COMT; the disease is Parkinson disease.