Type 1 diabetes and celiac disease share a common genetic origin, according to a new study, which suggests that the two disorders may also share a common cause.
In a study published in the New England Journal of Medicine, British researchers have identified seven loci (regions of a chromosome, which carry genetic material) common to the two diseases.
"These findings suggest common mechanisms causing both celiac and type 1 diabetes - we did not expect to see this very high degree of shared genetic risk factors," Prof. David van Heel from Barts and the London School of Medicine and Dentistry said in a statement.
Both type 1 diabetes and celiac disease are autoimmune disorders. In type 1, also known as juvenile, diabetes, the body attacks specific cells in the pancreas, known as beta cells, which limits its ability to produce insulin to regulate blood-sugar levels.
Celiac disease is an intolerance to gluten, a protein found in wheat, barley and rye, which triggers an attack on the small intestine.
The study suggests that type 1 diabetes and celiac disease may be caused by similar underlying processes. These include tissue damage from an autoimmune response (when the body attacks itself, as in type 1 diabetes) or an intolerance to a dietary antigen (a foreign substance that triggers an immune response, as in celiac disease).
The researchers believe that the loci regulate the mechanisms that cause the body's immune system to attack the small intestine and the cells in the pancreas.
"The next step is to understand how these susceptibility genes affect the immune system, and to keep exploring environmental factors that might alter the risk of type 1 diabetes, which results from an incredibly complex interaction between nature and nurture," Prof. John Todd of the University of Cambridge said in a statement.
The researchers gleaned their data from more than 8,000 tissue samples from people with type 1 diabetes, more than 2,500 tissue samples from celiac disease patients and more than 9,000 samples from control subjects.
