Research has demonstrated that levodopa may have acute or short‐term beneficial24, 25 or detrimental26, 27 effects on cognitive performance; however, there is no evidence initial choice of dopamine replacement therapy (DRT) makes a difference in terms of subsequent dementia,28, 29 and a trial of a selective monoamine oxidase B inhibitor was negative for treatment of PD‐MCI.30 The gene discussed is MAOB; the disease is Parkinson disease.