Having discussed how to evaluate the practical usefulness of genetic testing and keeping it in perspective, I’m now ready to briefly discuss some specific tests. This is a rapidly evolving field and as we learn more about it, I’ll seek to keep you up to date. The following are tests related to cardiovascular disease prevention:
- 9P21 genotype – This is the so called “heart attack gene”. It’s very common in our population and conveys a higher risk for severe coronary artery disease at a younger age if homozygous (gene from both parents). Uncontrolled diabetics with the gene have a 400 percent increased risk for heart disease and double the risk of death. Those homozygous also have a far higher risk for abdominal aortic aneurysm.
How can this test make a difference? It can provide strong motivation for change especially in someone with minimal risk factors who thinks they are safe. Also it increases motive to control blood sugar. Finally, an argument could be made to do an ultrasound on the abdominal aorta to screen for aneurysm.
- Apo E genotype – This test has been most in the news as a predictor of Alzheimer’s disease. The gene has 3 variants, E2, E3 and E4, with E4 having the highest Alzheimer’s risk. Recommendations for a healthy diet and the effects of alcohol consumption are reportedly affected by these variants. Apo E 4 types have a higher risk of heart disease and are apparently more sensitive to saturated fats and alcohol. Some have even suggested an old fashioned low fat diet for these folks. It should come as no surprise that I am very skeptical of this advice. Among other issues, many E4’s have metabolic syndrome (pre diabetes) or diabetes. I’ll need time to review the studies and gain more experience with this test but promise to get back to you with some practical advice.
We’ll cover 3 more interesting and possibly useful genetic tests on Wednesday – KIF6, Interleukin 1 and Haptoglobin. I would welcome your questions or comments. Perhaps a reader has already benefited from genetic testing and would like to share their experience.