Rheumatoid arthritis drug (thiopurine) increases risk of pancreatitis depending on your genes

People with a particular genetic variation are four times more likely to develop pancreatitis if they are prescribed thiopurine, a group of drugs used for rheumatoid arthritis and inflammatory bowel disease, says research published in Nature Genetics.
Experts found that 17% of people who have two copies of a particular genetic marker are likely to go on to develop pancreatitis if they are prescribed thiopurine drugs (such as azathioprine and mercaptopurine).
It is already known that about 4% of people who are prescribed these drugs develop pancreatitis, an inflammation of the pancreas, which can be fatal. But the new work identified a group of patients whose genetic make-up means they are more than four times more likely to develop the condition when given these drugs.
Over 150 hospitals from around the world collected genetic data on people with irritable bowel disease who developed pancreatitis to allow the team to identify regions of the genome that could make people more susceptible to developing this serious drug side effect.
The team found a genetic marker in the HLA area of the genome, which is associated with how the body responds to infection. People with two copies of the marker had a 17% chance of developing pancreatitis after being given a thiopurine, while those with one copy had a 9% chance.
“We can now theoretically identify which patients could be at increased risk of developing pancreatitis,” explains Dr Graham Heap who is involved in the work. “We are hoping that this test will be formed into a tool kit of DNA based tests that also assess other important side effects of these drugs such as liver damage or white blood cell counts. We would then be able to use this to identify at-risk patients and ultimately save lives.”

Image credit: Johannes Ahlmann