Furthermore, potential interactions between the APOE and PICALM genes have been observed.7 Some studies suggest that the combined presence of these genes influence brain atrophy and diminishes cognitive performance in early AD patients.9 Both genes are also implicated in amyloid pathology, a common pathway in the development of AD.10 They have never been studied together in a non-demented population. Here, APOE is linked to Alzheimer disease.