Edinburgh scientists find gene clue for flu mystery
Scientists have discovered a gene which may make some people more susceptible to flu.
The gene was found by Edinburgh University researchers working with the Wellcome Trust Sanger Institute near Cambridge.
It may explain why apparently healthy people have needed intensive care after contracting swine flu, while others were unaware they had been infected.
The findings have been published in the journal Nature.
An analysis of the DNA of 60 patients in intensive care with flu revealed an unusually high number with a variant in a gene called IFITM3.
This gene produced a protein which hinders the spread of the flu virus in the lungs. The variant in this gene means less protein is produced and the flu virus can spread more easily.
Although the genetic variation is normally rare, it was 19-times more common than expected in people who needed hospital treatment.
Dr Kenneth Baillie, an expert in genetics and critical care at Edinburgh University's Roslin Institute, said: "During the pandemic it was very unusual for a healthy person to become desperately sick with flu but it did happen to some people.
"It was a mystery why it affected those people so severely when most people were hardly affected at all. This research explains a fraction of why those individuals were so susceptible."
It is the first time a gene has been linked to the body's defences and could be used to screen for those most in need of vaccination.
Dr Baillie added: "You'd think of a virus as something that either infects you or it doesn't.
"In fact we know that your chance of getting an infectious disease is more strongly passed on in families than heart disease or cancer.
"Infectious diseases are themselves genetic. This is the first observation that a particular gene leads to susceptibility to flu."