Thus, here we specifically tested cerebrospinal fluid (CSF) biomarkers for the diagnosis of AD (Aβ1-42, total tau (t-tau) and phosphorylated tau (p-tau181) and dementia with Lewy bodies (DLB) (α-synuclein), MRI hippocampal and occipital pathology for the diagnosis of coincident DLB and medial temporal lobe (MTL) pathologies and occipital hypometabolism for the diagnosis of DLB. This evidence concerns the gene MAPT and Alzheimer disease.