DRD2 and Parkinson disease: D4R itselfcomprises 10 different genotypes, with D4.2, D4.4, and D4.7 being the most prevalent of these.10−12 The pharmacological management of PD currently focuses primarilyon enhancing dopamine signaling through D2R, such as byproviding dopamine precursor therapy with levodopa or through directagonism with pramipexole or ropinirole.13−25