Researchers from Brown University and Banner Alzheimer's Institute have found that infants who carry a gene associated with increased risk for Alzheimer’s disease tend to have differences in brain development compared to children without the gene. The study, published in JAMA Neurology, demonstrates some of the earliest developmental differences associated with a gene variant called APOE ε4, a common genotype and a known risk factor for late-onset Alzheimer’s.
The researchers imaged the brains of 162 healthy infants between the ages of two months and 25 months. All of the infants had DNA tests to see which variant of the APOE gene they carried. Sixty of them had the ε4 variant that has been linked to an increased risk of Alzheimer’s. Using a specialized MRI technique, the researchers compared the brains of ε4 carriers with non-carriers. They found that children who carry the APOE ε4 gene tended to have increased brain growth in areas in the frontal lobe, and decreased growth in areas in several areas in the middle and rear of the brain. The decreased growth was found in areas that tend to be affected in elderly patients who have Alzheimer’s disease.
Researchers emphasized that the findings do not mean that any of the children in the study are destined to develop Alzheimer’s or that the brain changes detected are the first clinical signs of the disease. What the findings do suggest, however, is that brains of APOE ε4 carriers tend to develop differently from those of non-ε4 carriers beginning very early in life.