New Genome Wide Association Study Reveals Heritable T2D Genes

Type 2 diabetes (T2D) is becoming a global health issue, with epidemic proportions being reported in many European Union countries after the US declared epidemic proportions over a decade ago.  While there has been controversy over whether ever-increasing portion sizes combined with excess refined sugars may be to blame, there is increasing evidence that genetic factors play a much larger role than previously imagined.  With this thought in mind, investigators from Oxford University’s Wellcome Trust Centre for Human Genetics led the largest ever genetic study of type two diabetes, involving researchers from 20 countries on four continents.

DNA
Image/Karol Langner

The study used DNA data from 49,000 afflicted individuals and 139,000 healthy controls to run a genome-wide association study (GWAS).  The goal of a GWAS is to identify discrepancies between particular genes or gene regions in diseased versus healthy individuals in order to identify where a particular disease or trait may originate.  This technique was used to compare the 188,000 individual DNA samples in an effort to determine the differences between healthy and afflicted individuals, and to compare all the diabetic patients for potential markers that can be used clinically to diagnose T2D or pre-T2D.

The researchers reported two major findings.  First, there are seven comparable regions between all diabetics that that are genetically altered in relation to the healthy controls.  Two of these regions are directly involved in regulating the genes ARL15 and RREB1, which are involved in glucose and insulin increases throughout the body, hallmarks of T2D. 

Second, and most profoundly, the researchers found genetic variations differ in populations with varying backgrounds that live in the same area.  This means, for example, that if two neighbors of different ethnic backgrounds eat the same meals everyday for their whole lives, one may still end up with T2D while the other will not.  While this example may be rare, the overarching theme is that eating habits of certain areas of a country, say the South versus the West in the US, may not have as much to do with T2D risk as initially thought.

This is the first time T2D risk has been successfully and clearly linked to genetic differences among ethnic populations.  Building on this success, principal investigator Dr. Andrew Morris said in a press release that this technique will “be able identify new DNA variants influencing risk of heart disease and some forms of cancer, for example, which are shared across ethnic groups. It has the potential to have a major impact on global public health”.

Edward Marks is a PhD student at the University of Delaware.  His research involves the healing of burns and other chronic wounds using nanomedicine techniques, with the goal of pushing any advancement directly into the clinic.  Edward received his BS from Rutgers University and Masters from the University of Delaware.