Gene variants confer diabetes protection, researchers say

6 March 2009

Rare genetic mutations that confer protection against developing type 1 diabetes have been found. Furthermore, the nature of the mutations suggests that the disease may be caused by a common virus.

The mutations - four variations in a gene called IFIH1 - were identified by scientists from the Juvenile Diabetes Research Foundation/Wellcome Trust Diabetes and Inflammation Laboratory, in Cambridge. People carrying any of the four variants had a decreased risk of developing type 1 diabetes.

Type 1 diabetes is an autoimmune disorder that causes the body to attack its own insulin-producing cells in the pancreas.

The researchers conducted genome-wide association studies, scanning the whole genomes of 480 patients with diabetes and comparing them with 30 000 people, including a large number of diabetes patients or their families, to look for variations in IFIH1 that could be linked to the disease. IFIH1 is found in an area of the genome strongly associated with type 1 diabetes.

The gene produces a protein that helps activate the immune system to fight viruses. Specifically, it targets a class of virus that includes enterovirus, an infection commonly found in patients newly diagnosed with type 1 diabetes.

The researchers suggest that enterovirus infection prompts IFIH1 to activate the immune system, which may trigger it to attack cells in the pancreas. Since the four protective variants affect the function of the IFH1 protein, this might explain how they decrease risk of developing the disease. Further research is required to confirm the link, however.

Professor John Todd, senior author on the study, said, "We have been able to pinpoint one particular gene among a long list of candidates. Now we and others can begin to study the biology of IFIH1 in the context of type 1 diabetes, knowing that it is part of the cause of the disease."

Image credit: Wellcome Images

Reference

Nejentsev S et al. Rare variants of IFIH1, a gene implicated in antiviral responses, protect against type 1 diabetes. Science, published online before print 5 March 2009.