Type 2 diabetes is becoming a national health crisis. According to the CDC, the number of people with diabetes has tripled in the past twenty-five years, and the numbers continue to grow. Click on the image below to see an estimate of diabetes prevalence.
In the next image, people shown in darker blue are TT (two copies of the higher risk form of the TCF7L2 gene). In most groups of people, approximately 1 out of every 10 people are TT, so it's quite common. The lighter blue people are either CT or CC (lower risk). Of all the people shown, which ones do you predict will develop diabetes? Click on the 'play' arrow to see.
The answer may have surprised you. The darker blue people are at higher risk for diabetes. This is seen by the fact that two or three people from each darker blue column develop diabetes. Compare this to the lower risk group. In each column of lighter blue people, only zero, one, or two people develop diabetes.
In spite of the higher risk, the image shows that most people with the higher risk form of TCF7L2 did NOT develop diabetes. Also, in spite of having a lower risk form of the TCF7L2 gene, a significant number of lighter blue people did develop diabetes. The image shows that, although TCF7L2 is a diabetes risk gene, TCF7L2 alone is not a good predictor of who is likely to develop diabetes.
TCF7L2 is the most significant diabetes risk gene, but there are many other genes that contribute to diabetes risk. Research on risk genes is leading to a better understanding of the genetic basis of health problems like diabetes. As research continues, increased knowledge of risk genes is expected to lead to more powerful approaches to disease prevention and treatment.
