Celiac Disease and Type 1 Diabetes Share Genetic Risk Factors

In The New England Journal of Medicine this week, British researchers at the University of Cambridge and Barts and The London School of Medicine and Dentistry report their discovery that genetic traits for celiac disease and type 1 (juvenile) diabetes overlap to a much greater extent than anyone had realized.

Like celiac disease, type 1 diabetes is an autoimmune disorder. Whereas in celiac disease, the body attacks the small intestine (if patients eat gluten), in type 1 diabetes the body attacks the pancreas, limiting the ability of its beta cells to produce insulin.

The researchers analyzed DNA from 8064 people with type 1 diabetes, 2560 people with celiac disease, and 9339 people without either condition. They found that celiac disease and type 1 diabetes share seven chromosome regions.

According to a press release from the University of Cambridge, the seven regions where the genetic traits overlap are believed to regulate the mechanisms that cause the immune system to attack both the pancreas and the small intestine. This suggests that celiac disease and type 1 diabetes share the same underlying mechanisms and could have similar environmental triggers (such as intolerance to antigens in food).

Indeed, the researchers point out that "cereal and gluten consumption might be an environmental factor in type 1 diabetes, leading to the alteration of the function of the gut immune system and its relationship with the pancreatic immune system."

One of the researchers, Professor David van Heel from Barts and The London School of Medicine and Dentistry, said in the press release: "We did not expect to see this very high degree of shared genetic risk factors."

The senior author of the report, Professor John Todd of the Cambridge Institute for Medical Research at the University of Cambridge, told U.S. News & World Report, “Almost every celiac disease susceptibility gene had an effect in type 1 diabetes."

Dr. Robert M. Plenge from Brigham and Women’s Hospital in Boston put it another way in the editorial he wrote to accompany the main article in The New England Journal of Medicine: “Do [genes] that are associated with a risk of celiac disease also confer a risk of type 1 diabetes, and do [genes] that are associated with a risk of type 1 diabetes also confer a risk of celiac disease? The answer [is] a resounding yes.”