Currently prescribed treatments for PD are levodopa with 1-amino acid decarboxylase inhibitors, dopamine agonists (pramipexole, ropinirole, rotigotine), MAO-B inhibitors (selegiline, rasagiline), catechol-O-methyltransferase inhibitors (entacapone), and anticholinergic drugs [415], while refractory cases may undergo surgical deep brain stimulation procedures. The gene discussed is MAOB; the disease is Parkinson disease.