A team of researchers uncovered a specific gene variant linked to an adverse drug reaction resulting in liver injury in people with multiple sclerosis. It is the first time researchers have been able to establish a validated genetic marker for a drug-induced harm in people with MS. The findings inform a broader understanding of genetic risk of drug reactions in MS and may lead to clinically useful tests for more individualized approaches to MS treatment and care.

According the researchers at the University of British Columbia, one in 50 people with MS who are treated with interferon-beta, one of the most commonly prescribed MS therapies, will develop abnormally high levels of liver enzymes. They found that the risk of liver injury increases eight fold with this marker. They said it's important to be able to understand who might be most at risk so physicians can intervene with an altered treatment plan or increased monitoring to prevent liver damage.

The genetic marker was identified with the help of 150 patients from five Canadian clinics and then validated in 120 patients from three sites in the U.S. and one in Sweden.

Liver injury is a common side effect of many drugs, but this is the first time researchers have connected a genetic marker with a biologic drug and elevated risk of liver injury. Currently people with MS have their blood monitored for increased liver enzymes, which can indicate potential injury.

Interferon-beta is a first-generation MS drug that is prescribed to treat the relapse-remitting form of the disease. The biologic drug works with an individual's own interferons – naturally occurring molecules – that exist in the body to reduce inflammation.

The study was published the journal Nature Genetics.