The Movement Disorders Society Research criteria for prodromal PD combine the published likelihood ratios of readily available risk and presenting factors and of more specific investigations such as dopamine transporter (DAT) imaging.12 However, these were derived from multiple individual studies and are designed for active screening of populations; predictive tools to identify those in the prodromal phase of PD from primary care presentations are lacking. This evidence concerns the gene SLC6A3 and movement disorder.