A new study has identified four locations in the genome associated with a risk for the most common type of hernia, offering 
researchers insight into the possible genetic mechanisms that make some people more likely than others to develop this painful condition.
“Surgical repair of inguinal hernias is one of the most commonly performed operations in the world, yet little is known about the genetic mechanisms that predispose individuals to develop them,” said Eric Jorgenson, PhD, research scientist at the Kaiser Permanente Division of Research.
The study, by scientists from Kaiser and the University of California at San Francisco, is the first large-scale genetic study looking at the risk of inguinal hernias in adults. As part of the study the findings were replicated using 23andMe’s data.
Researchers started by conducting a Genome Wide Association Study using data from Kaiser Permanente’s large patient research database, called the Genetic Epidemiology Research in Adult Health and Aging cohort.
Along with genetic data from 110,000 people, this cohort also includes participants’ electronic medical records. This allowed researchers to look specifically for genetic associations among patients who’d undergone surgery for a hernia. That first step revealed four specific locations in the genome associated with risk for having a hernia.
With that information, researchers at UC San Francisco then look more deeply at the biology around those genetic locations. They looked at how those genes – involved in the development of connective tissue in the body – expressed themselves in mice. What they found that at least two of these genes or gene regions operate in the same biological pathway, according to Nadav Ahituv, PhD, associate professor at UCSF’s Department of Bioengineering and Therapeutic Sciences.
The researchers believe that the findings suggest that gene regions identified in this study influence susceptibility for hernias because they regulate both collagen and elastin in the body, influencing the strength of connective tissue.
Hernias develop often when pressure or strain pushes an organ or other tissue through a weak spot in surrounding muscle or connective tissue. This often happens in the groin or stomach area, and can be very painful and can lead to several complications if the hernia also cuts off blood flow.
Men carry a much higher lifetime risk for the condition – more than four times as likely – than women whose lifetime risk is about six percent. But for both men and women the risk of developing a hernia increases as they age.
The authors said the study will help guide further research and may help identify more effective treatments to prevent hernias.