ABCA1 and Alzheimer disease: The data demonstrated that AD-association was mainly explained by extremely rare variants, but also by a smaller number of more common variants, e.g., N1800H.159 Intriguingly, loss of function and missense variants in the ABCA1 gene were respectively associated with a 4.7-fold (95%CI 2.2-10.3) and 2.7-fold (95%CI 1.9-3.8) increased EOAD risk, and this was lower for LOAD cases suggesting that the burden of damaging ABCA1 variants was concentrated in younger AD patients.