Science & Research

Alzheimer’s-linked gene affects babies’ brains

Researchers found differences in myelination rates in the brains of infants carrying the gene

By
Staff Writer
Friday, December 6, 2013

Brains of infants carrying a gene associated with Alzheimer’s disease develop differently than those of non-carriers, according to a recent study published by researchers at Brown and Banner Alzheimer’s Institute in Phoenix.

The study, published Nov. 25 in the journal JAMA Neurology, details the differences in brain development between children who carry the APOE epsilon-4 gene variant linked to late-onset Alzheimer’s and children who are non-carriers.

“This gene is influencing brain development early on, and these differences may confer some type of risk later in life that eventually leads to Alzheimer’s or other disorders,” said study co-author Douglas Dean III GS. But, he added, the differences in brain development associated with the gene are not diagnostic. “By no means are we saying these kids are going to develop Alzheimer’s.”

The APOE gene is linked to several different bodily functions, including lipid maintenance and the development of cholesterol, Dean said.

Dean worked with Assistant Professor of Engineering Sean Deoni, who oversees Brown’s Advanced Baby Imaging Lab, to test the subjects’ DNA for the APOE epsilon-4 gene. Sixty of the 162 2 to 25 month-old subjects carried the ε4 variant of the APOE gene.

Researchers found the rate of the developing myelin, a lipid-rich substance that protects nerve fibers, differed between carriers and non-carriers of the gene variant.

“We found that the carriers had more myelin earlier on, but they developed at a slower rate,” Dean said. “Although the non-carriers had less myelin, they eventually caught up and surpassed the carriers.”

The researchers also found that carriers tended to have decreased growth in the middle and back parts of their brains, which have been found to be affected by Alzheimer’s in elderly subjects, according to a University press release.

It was difficult to work with so many young subjects,  Dean said, but Brown’s Advanced Baby Imaging Lab has developed a reduced-sound brain imaging technique that lets children be scanned while sleeping without the aid of medication.

“While these findings are statistically significant, they are not clinically significant,” said Eric Reiman, CEO of Banner Research.

Researchers hope to conduct a longitudinal study to determine how the subjects’ brains develop over time, he said. “We think there’s an opportunity here to begin to understand how a range of inherited genes can influence the changes that occur during development.”