Genetic risk of type 2 diabetes
Common diseases such as type 2 diabetes (T2D) occur at the interface of genes and the environment, as both inherited as well as lifestyle and other health risk factors play important roles in the disease process. As a result, it is important to understand what carrying an inherited risk variant for a common disease means, and how that information can help to keep a predisposition to a given condition from ever developing into a disease.
According to the American Diabetes Association, one third of Americans with diabetes are not even aware that they have the disease, and a further 54 million Americans have pre-diabetes.
In the most basic terms, carrying a genetic risk variant for a common disease does not mean that one will necessarily develop the disease; and not having a certain risk variant does not eliminate the possibility of getting the disease. Rather, for the common diseases, genetic risk variants impact the likelihood that one may develop the disease.
Understanding this inherited risk is empowering information with potentially important clinical utility. This is particularly true in a disease like T2D, in which specific lifestyle and health factors are known to play such an important part. By understanding inherited risk, it may be possible to take preventive action through lifestyle modification or by taking certain medications to minimize the likelihood of an individual ever developing a disease.
deCODE T2TM, like other DNA based tests for common disease, is therefore a risk assessment test as it measures DNA risk markers that are not determinative but associate with the disease in certain proportion of the patients. Patients with higher genetic risk are not destined to develop T2D and conversely, patients with lower genetic risk are not immune from diabetes. There are other risk factors not measured by the deCODE T2TM test. DNA markers for common disease simply are risk markers just as blood cholesterol is for cardiovascular diseases or PSA for prostate cancer.
The deCODE T2™ genetic risk profile is independent of other risk factors for type 2 diabetes such as family history, obesity, prediabetes, and ethnicity. The genetic risk can be multiplied by the other risk factors not measured by the test to derive a composite risk relative to that in the general population. Therefore, this test may be useful for patients with or without family history of T2D.
The deCODE T2TM results defines risk range from 0.6 to 2.2 fold the risk of the general population. About 40 % of the population has a genotype combination of the tested markers that have an increased relative risk (>1) over the general population, about 8% of the population have 1.5 to 2.2 relative risk, about 3% of the population have genotype combinations that confer a 1.8 to 2.2 fold relative risk.
By knowing and understanding genetic risk, it may be possible to take actions that reduce or minimize the likelihood of individual developing diabetes.
In addition to predicting or recalculating the remaining lifetime risk of developing T2D, the deCODE T2TM results can predict the likelihood of those with prediabetis (impaired fasting glucose and impaired glucose tolerance) converting to full blown T2D and which patients may benefit the most from preventive management. Compared to the baseline risk of 30% in overweight or obese prediabetics to convert to T2D within 3 to 4 years deCODE T2 TM can identify those prediabetic patients who are at up to 70 % risk of converting to T2D within the same timeframe (Tuomilehto, J., et al., N Engl J Med, 2001. 344: 1343-50). These high-risk patients therefore may benefit the most from more aggressive management either through lifestyle modification or drug treatment. The American Diabetic Association states in it’s 2008 recommendations on management of prediabetics, that in addition to lifestyle counselling, treatment with the T2D drug metformin may be considered in those who are at very high risk and who are obese and under 60 years of age. deCODE T2 TM is one of the strongest risk factors for conversion.
deCODE T2 is performed in deCODEs, CLIA-registered laboratory. The test can only be ordered by qualified physicians and medical practitioners. If you are a doctor or medical professional, we invite you to learn more and how to order the test for your patients by clicking on the link below. If you are an individual interested in deCODE T2 TM, you can sit down with your doctor and continue through this site, or, to be put in touch with a doctor, you can also go to www.DNAdirect.com.
DNA direct will provide you all the professional services needed for obtaining the test and interpreting its results from the convenience of your home. Through their user-friendly website you will be provided with detailed pre- and post-testing information regarding the test and results, a simple cheek swab sampling kit that you can submit by mail, and the opportunity to discuss any questions you may have with qualified physicians and counsellors.