Although previous studies have shown that limbic hypermetabolism correlates with dopaminergic depletion in patients with DLB [41, 42] and RBD, [31] we could not evaluate the relationship between relative MTL hypermetabolism, dopamine transporter uptake, cognitive dysfunction, and motor parkinsonism because some of our patients with AD did not undergo FP-CIT-PET. The gene discussed is SLC6A3; the disease is Parkinson disease.