We performed PiB-PET in patients with probable RBD as a prodromal symptom of DLB (MIBG myocardial scintigraphy confirmed), and in those with probable DLB (MIBG myocardial scintigraphy and/or dopamine transporter imaging confirmed), and compared the rates of amyloid positivity between these two groups. This evidence concerns the gene SLC6A3 and Lewy body dementia.