Study links diabetes and coeliac
Type 1 diabetes and the food intolerance disorder coeliac disease appear to share a common genetic origin, UK research suggests. The genetic similarities are such it suggests they may also be triggered by similar environmental factors. This raises the possibility that the protein gluten, already known to cause coeliac disease, may also trigger type 1 diabetes. The study appears in the New England Journal of Medicine. Type 1 diabetes causes the body to attack the beta cells of the
pancreas, limiting its ability to produce the insulin necessary to
regulate blood sugar levels. In contrast coeliac disease attacks the small intestine. However, both conditions are the result of a malfunctioning immune system. In addition, the development and anatomy of the small intestine
and pancreas are closely related, and the gut immune system shares
connections with pancreatic lymph nodes, which have been linked to an
inflammation of the pancreas and the destruction of beta cells. The researchers, from the University of Cambridge and Barts and
The London School of Medicine and Dentistry, analysed nearly 20,000
tissue samples to look for genetic similarities between the two
conditions. Regulatory role They identified seven chromosome regions which are shared between the two diseases. The key regions are thought to regulate the mechanisms that
cause the body's own immune system to attack both the beta cells in the
pancreas and the small intestine. The researchers said more work was needed to pinpoint how genetic and environmental factors combined to trigger the conditions. The researchers stressed the interaction was likely to be complex,
but suggested that the same sort of environmental factors were likely
to trigger both conditions. In the paper, they write: "Our results support further
evaluation of the hypothesis 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." Researcher Professor David van Heel said: "These findings
suggest common mechanisms causing both coeliac and type 1 diabetes - we
did not expect to see this very high degree of shared genetic risk
factors." Karen Addington, of the Juvenile Diabetes Research Foundation,
which helped fund the study, "These studies demonstrate that type 1
diabetes and coeliac disease share far greater genetic overlap than had
been appreciated; which helps explain the high prevalence of both
conditions occurring simultaneously in an individual and may provide
new avenues for understanding the cause and mechanisms of both
conditions." Sarah Sleet, of the charity Coeliac UK, described the research
as a real advance in understanding a condition which is thought to do
undiagnosed in many people.
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