Medical genetics

The researches find that the genetic research and the availability of commercial genetics tests have put us in a very modern predicament we can now find out (quickly, easily and cheaply) whether we personally hold genetic risk factors that put us at a substantially increased risk of Alzheimer’s disease. In addition; we have recently shown that brain changes can be identified in people holding these genetic risk variants as early as 20 years old. Genetic research has revealed that some individuals carry variants of specific genes that confer an increased risk of developing Alzheimer’s disease in later life.

Commercial genetic tests

For example; carriers of the ε4 variant of the APOE gene are approximately; three to eight times more likely to be diagnosed with Alzheimer’s disease after age 60 than individuals without this variant. The more variants; the greater the risk with a maximum of one inherited from each parent. In our recent research; we looked at these genetic factors in young people (around 20 years old, on average). We split them into “higher-risk” and “lower-risk” groups depending on whether they did or did not carry the APOE-ε4 gene variant; respectively.

Using advanced brain imaging techniques; we were able to show that it is possible to detect subtle differences in particular brain networks for the “higher-risk” young adults; several decades before any clinical symptoms of Alzheimer’s emerge. While brain structure and function were significantly different between the risk groups on average, it is very important to point out that not all “higher-risk” individuals go on to develop Alzheimer’s disease. (Note that we say “higher” not “high” risk.)

Develop Alzheimer’s disease

The brains of many of these individuals were comparable to those at lower risk. This means carrying a higher-risk gene variant does not necessarily lead to early brain changes; or an Alzheimer’s diagnosis later in life. Public interest in genetics and gene testing is booming. Recent times have also seen highly publicised incidences of people responding to their own genetic risk with drastic interventions. For instance, Angelina Jolie, who has a faulty copy of the BRCA1 gene; associated with breast cancer and had elective surgery to remove both breasts and some of her reproductive organs.

“Direct to consumer” genetic testing kits sold by companies now provide people with convenient and affordable access to their personal genetic information; including their genetic risk for specific diseases; including Alzheimer’s. But the relatively low cost of these tests reflects the fact that they typically only cover a fraction of the genome. The results, therefore, neglect the contribution of the rest of the consumer’s genetic code. This will include other genes with protective, as well as negative; effects.