Apolipoprotein E2 homozygote has been associated with a protective effect against AD and contributes to delaying the onset of symptoms. However previously, no significant data had pointed to clinically confirmed AD in persons with apolipoprotein E2 homozygote. The reverse is true of apolipoprotein E4. Previous studies have confirmed that apolipoprotein E4 is a predictive risk factor for AD and indicates an increased genetic risk of AD.

Clinical confirmation of the apolipoprotein E2 homozygote Alzheimer's disease finding in this study was confirmed by MRI, PET and neuropsychological evaluation and testing. AD pathology is yet to be determined and will occur at post mortem.

"Clinical diagnosis of possible AD has now become extremely accurate and is especially helpful to physicians looking for the best outcomes in treating patients," says Marwan Sabbagh, MD, Sun Health Research Institute's chief medical/scientific officer and lead investigator of the study.

"This study may hold many clues to the nature of how Alzheimer's genetics work. Although clinically rare, the information gleaned in this study allows us to ask new questions and possibly answer others," says Sabbagh.

The article is "Possible Alzheimer's Disease in an Apolipoprotein E2 Homozygote" by Ignat Ignatov, Christine Belden, Sandra Jacobson, Donald Connor and Marwan N. Sabbagh. It is published in the Journal of Alzheimer's Disease 16:1 (January 2008).

Source: IOS Press