APOE epsilon 4 lowers age at onset and is a high risk factor for Alzheimer's disease; a case control study from central Norway. - Sando SB; Melquist S; Cannon A; Hutton ML; Sletvold O; Saltvedt I; White LR; Lydersen S; Aasly JO; Sando, Sigrid B; Melquist, Stacey; Cannon, Ashley; et al. (BMC Neurology, 2008)