As for PD-specific drugs, 47.2% early PD patients received carbidopa/levodopa, followed by monoamine oxidase B inhibitors (41.7%), dopamine agonist (8.3%), benzhexol hydrochloride (5.6%), and catechol-O-methyltransferase inhibitors (2.8%). The gene discussed is COMT; the disease is Parkinson disease.