There was a decrease in CSF orexin concentrations in DLB as compared to AD patients and controls. The observed differences in orexin levels were found to be specific to females with DLB patientsFemales with DLB also exclusively displayed lower levels of alphasynuclein compared to AD patients and controlsOrexin was associated to alphasynuclein and total Tau in female non-demented controls whereas associations between orexin and AB1-42 concentrations were absent in all groups regardless of gender. The gene discussed is MAPT; the disease is Alzheimer disease.