Altered brain white-matter integrity in non-demented carriers of the APOE ε4 allele: A risk for Alzheimer’s disease.

• Previous research has shown that polymorphisms of the apolipoprotein E (APOE) represent genetic risk factors for dementia and for cognitive impairment in the elderly. The neural mechanisms by which these genetic variations influence behavioral performance or clinical severity are not well understood. We used diffusion tensor imaging to investigate ultrastructural properties in brain white-matter to detect pathological processes that modify tissue integrity. Sixty participants were included in the study of which 30 were homozygous for the APOE ε3 allele, 10 were homozygous for the APOE ε4 allele, and 20 had the APOE ε34 allele combination. All individuals were non-demented, and the groups were matched on demographic variables and cognitive performance. The results showed a decline in fractional anisotropy, a marker for white-matter integrity, in the posterior corpus callosum of ε4 carriers compared to non-carriers. Additional sites of altered white-matter integrity included the medial temporal lobe. Conclusions: Although the mechanism underlying vulnerability of white matter tracts in APOE ε4 carriers is still unknown, our findings suggest that increased genetic risk for developing AD is associated with changes in microscopic white-matter integrity well before the onset of dementia.

Ämnesord

SAMHÄLLSVETENSKAP  -- Psykologi (hsv//swe)

SOCIAL SCIENCES  -- Psychology (hsv//eng)

Nyckelord

brain white matter

healthy carriers

genetic risk factors

elders

apolipoprotein E

Alzheimers disease

memory

genetics

brain imaging

Psychology

Psykologi

Publikations- och innehållstyp

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