Indicative biomarkers include reduced dopamine transporter (DAT) uptake in the basal ganglia using Single Photon Emission Computed Tomography (SPECT) or Positron Emission Tomography (PET) imaging, REM sleep behavior disorder (RBD) using Polysomnography (PSG), and reduced uptake on 123Iodine-metaiodobenzylguanidine myocardial scintigraphy (123I-MIBG) (1), which can assist in differentiating DLB from AD and most other causes of dementias with the exception of Parkinson’s disease (PD) dementia. The gene discussed is SLC6A3; the disease is REM sleep behavior disorder.