Signs of Alzheimer's disease emerge as early as childhood in people who carry a high-risk gene for the brain-wasting condition, according to new research from the Center for Addiction and Mental Health of Toronto.
 

In a study published online in the journal Molecular Psychiatry, the finding holds out the prospect that notable changes in the changes in the brains of such individuals could be identified decades before symptoms emerge and might be used to flag those at risk.
 

The Alzheimer's gene, called SORL1, is one of a number of genes linked to an increased risk of the late-onset form of the disease.
 

"We need to understand where, when, and how these Alzheimer's risk genes affect the brain, by studying the biological pathways through which they work," said lead researcher Aristotle Voineskos, M.D., head of the Kimel Family Translational Imaging-Genetics Laboratory at CAMH. "Through this knowledge, we can begin to design interventions at the right time, for the right people."
 

For the study, the researchers studied nearly 1,000 individuals both with and without Alzheimer's disease to identify genetic differences in SORL1, and see if there was a link to changes in the brain, using imaging as well as post-mortem tissue analysis. In each approach, a link was confirmed.
 

Dr. Voineskos noted that risk for Alzheimer's disease results from a combination of factors — unhealthy diet, lack of exercise, smoking, high blood pressure combined with a person's genetic profile — which all contribute to the development of the illness.
 

"The gene has a relatively small effect, but the changes are reliable, and may represent one 'hit,' among a pathway of hits required to develop Alzheimer's disease later in life," he said.

He added that by identifying the genetic changes, at-risk "individuals can take measures in their own lifestyle to reduce the risk of late-onset Alzheimer's disease."