APOEe4, a gene associated with Alzheimer's disease risk, doesn't appear to directly affect memory performance or brain activity in older adults without cognitive impairment. However, the gene does seem to influence brain regions and systems that older at-risk adults activate to support successful memory recall.
Genetic analysis of almost 4,300 samples reveals a link between the appearance of amyloid deposits, APOE, and a novel gene called RBFOX1. Lower levels of RBFOX1 in the brain appear to be associated with increased amyloid and global cognitive decline over a person's lifetime.
APOE4, a gene implicated as a risk factor for Alzheimer's disease, triggers leaks in the blood-brain barrier. The damage to capillaries APOE4 causes correlates with increased levels of cyclophilin, a protein that causes the inflammation that is a signature of early Alzheimer's.
APOE4 increases the inflammatory response of human microglia while reducing cellular migration. The gene also impairs the metabolic activity of the immune cells. The findings show APOE4 has a profound impact on the basic functions of microglia.
While being multilingual did not delay the onset of dementia for those at risk, nuns who spoke four or more languages were significantly less likely to develop dementia than those who spoke just one language.
Middle-aged people with the Alzheimer's related APOE4 gene have a harder time accessing recently acquired knowledge, even when they show no symptoms of memory decline.
A new blood test for Alzheimer's disease is up-to 94% accurate at predicting dementia before symptoms appear. The test's accuracy is increased when genetic predisposition and age are taken into account. The new test may eventually replace PET neuroimaging, currently considered the gold standard, for early detection of Alzheimer's.
Children with the APOE E4 gene perform lower on verbal and general IQ tests than their peers without the genetic risk factor. APOE E4 is a genetic risk factor for Alzheimer's disease. The study suggests the effects of the gene manifests before adulthood and could be the earliest biomarker for later vulnerability to Alzheimer's disease.
Post mortem examinations of brain tissue from Alzheimer's patients revealed synapses contained clumps of clusterin, in addition to amyloid beta. The clumps were more abundant in those with genetic risk factors from Alzheimer's disease.