Gene discovery could lead to new cold sore treatments
MedWire News: US researchers have discovered a gene that influences the development of cold sores, and shown that some forms of the gene increase the risk for recurrent outbreaks while other forms have a protective effect.
"This discovery could have important implications for the development of drugs that affect cold sore frequency," write Dr John Kriesel (University of Utah, Salt Lake City), who led the study, and coauthors in the Journal of Infectious Diseases.
Cold sores are caused by infection with a virus called herpes simplex virus type 1 (HSV-1). Once infected, the virus can never be eliminated; instead, it lies dormant within the body's nervous system and can be reactivated at any time.
More than 70% of the US population is thought to be infected with the HSV-1 virus, but not all will develop cold sores. Of those that do, some people suffer outbreaks every few weeks or so while others may have an outbreak only once every 5-10 years.
"Researchers believe that three factors contribute to HSV-1 reactivation: the virus itself, exposure to environmental factors, and genetic susceptibility," explain Dr Kriesel and colleagues. "The goal of our investigation was to define genes linked to cold sore frequency."
For their study, the researchers recruited 335 people who were known to be infected with HSV-1 and asked them how often they developed cold sores. They then obtained a blood sample from each participant and extracted DNA for genetic analysis.
Dr Kriesel's team found that variations in a little-known gene called "C21orf91," located on chromosome 21, was strongly associated with how often the participants developed cold sores.
There were five major variations in the gene: two appeared to protect against HSV-1 reactivation while two increased the chance of outbreaks.
In view of their findings, the researchers propose re-naming the gene the "Cold Sore Susceptibility Gene-1", or CSSG1.
Dr Kriesel and colleagues say that more research is needed to confirm their findings in other groups of individuals, and hope that in the future the discovery could lead to new treatments for HSV-1, for which there is currently no cure.
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By Joanna Lyford