In reply
We thank Corder and colleagues for their comments on our recent study1 and we are pleased that they agree with our conclusion that ApoE genotype does not appear to significantly influence rate of cognitive decline in AD. In their letter, Corder et al also raised 2 other issues regarding our study.The authors correctly note that the study by Corder et al2 did not report "longer survival in ε4 carriers." In addition to the study by van Duijn et al,3 those findings should have been correctly attributed to DeKosky et al4 and not to Corder et al,2 as indicated by the reference numbers in the text of our article. We apologize for the confusion this oversight created.Corder et al state that we "argue against the existence of an ε4 gene-dose effect on the risk of becoming affected [with AD]." Our study on rate