Gene variant that increases flu risk found

Researchers with the Wellcome Trust Sanger Institute and the Center for Respiratory Infection at Imperial College London have linked a variant of a gene with increased flu hospitalization risk in the general population.

The IFITM3 gene was found to be much more common in people hospitalized with the flu. The gene controls a malformed protein, which creates increased susceptibility to viral infection. The researchers conducted a study on mice in which they removed the gene and found that flu symptoms were much worse, BBC reports.

The researchers then found that one out of 20 people in the hospital with the flu had the gene. The gene is present in approximately one in 400 people in the general population. The researchers plan to replicate the findings in larger studies.

"At the moment, if someone is in a more vulnerable group because of co-morbidity (another health problem), they would be offered the flu vaccine," Paul Kellam, a professor from the Sanger Institute and the co-leader of the study, said, according to BBC. "This is the idea here. Our research is important for people who have this variant as we predict their immune defenses could be weakened to some virus infections."

Peter Openshaw, the director of the Center for Respiratory Infection, said that the discovery vindicates the conviction that there was something unusual about patients hospitalized due to the flu.

"During the recent swine flu pandemic, many people found it remarkable that the same virus could provoke only mild symptoms in most people, while, more rarely, threatening the lives of others," Sir Mark Walport, the director of the Wellcome Trust, said, according to BBC. "This discovery points to a piece of the explanation: genetic variations affect the way in which different people respond to infection. This important research adds to a growing scientific understanding that genetic factors affect the course of disease in more than one way. Genetic variations in a virus can increase its virulence, but genetic variations in that virus's host - us - matter greatly as well."