Cold Sores Due to a Single Gene

Specifically, individuals who suffer from cold sores triggered by Herpes Virus Simplex - 1 (HSV-1) several times a year may have a single nucleotide polymorphism in their gene C21orf91 – dubbed rs1062202. Researchers have suggested it be called by the more "easy-to-remember" name Cold Sore Susceptibility Gene 1 (CSSG1).

Having this genetic change of swapping a thymine to a cytosine nucleotide was significantly associated (p=0.0047) with more frequent cold sores. Analysis has also found collections of 5 variants that are transmitted together with the C21orf91 gene of which two seemed to be neutral in terms of cold sore frequency, one was protective, and two were associated with increased susceptibility.

What does this all mean for an individual? It means if your parents get them a lot, than you may too.

Such individuals may benefit from regular use of anti-viral antibiotics to prevent such frequent recurrences.

Reference:
C21orf91 genotypes correlate with herpes simplex labialis (cold sore) frequency: Description of a cold sore susceptibility gene. J Inf Dis 2011; DOI: 10.1093/infdis/jir633.