Higher motor scores in the HNM-PD group than in the LNM-PD group remained significant after controlling DAT binding to the sensorimotor striatum as well as age, gender, and motor symptom duration in each patient, suggesting that despite similar dopamine depletion, the LNM-PD group has significantly fewer motor deficits than the HNM-PD group. The gene discussed is SLC6A3; the disease is Parkinson disease.