Genetic Linkage Found in Coeliac Disease

British scientists have found four closely linked genes on chromosome 4 that harbor variants protecting against development of coeliac disease.

Coeliac disease is an autoimmune disorder of the small intestine caused by a reaction to a gluten protein found in wheat, rye and barley, requiring affected individuals to eat a gluten-free diet.

David van Heel and colleagues at Queen Mary University carried out a genome-wide association study for coeliac disease, initially looking at a group of affected and unaffected individuals in the United Kingdom.

In addition to associations in the human leukocyte antigen region, which had been reported previously, they identified a protective variant in a region containing the genes IL2, IL21, TENR, and a predicted gene of unknown function, KIAA1109. That association was replicated in populations from the Netherlands and from Ireland.

The genes IL2 and IL21 are considered the two most promising genes to explain the association, since they encode interleukin-2 and interleukin-21 — proteins known to be involved in other intestinal inflammatory diseases. The researchers said further mapping will be required to pin down the mechanisms by which the variants protect against coeliac disease.

The study appears online in the journal Nature Genetics.