A decrease of reelin expression in the hippocampus occurs during normal aging and is associated with cognitive decline and with the appearance of amyloid β (Aβ) plaques [19-21] Moreover, a recent study demonstrated that intracellular expression of Aβ in layer II of the entorhinal cortex is limited to reelin-immunoreactive neurons of AD patients and in a rat AD model, during the pre-plaque stage, suggesting a physical interaction between reelin and intracellular Aβ [21]. Here, RELN is linked to Alzheimer disease.