ABCA1 and Alzheimer disease: These animal and cellular model studies, together with genetic studies that revealed AD to be associated with polymorphism in ABCA1 [189, 190] as well as with the related transporter ABCA7 [191], suggest that apoE4 is lipidated less effectively by ABCA1 and that the resulting hypolipidated apoE4 plays an important role in mediating the pathological effects of apoE4.