Conversely 123I‐isoflupane dopamine transporter uptake has been demonstrated to be upregulated in non‐PD GBA carriers compared with controls and is higher in GBA PD compared to idiopathic PD cases.14, 15GBA mutation carriers without PD exhibit prodromal PD features,16, 17, 18, 19 which progress with time.20 This evidence concerns the gene SLC6A3 and Parkinson disease.