New genetic marker for aortic aneurysms

Researchers identify new genetic marker for aortic aneurysm risk

University of Otago researchers have played a major role in a multi-national collaboration identifying a new genetic marker for increased risk of abdominal aortic aneurysm (AAA) and other common diseases of the arteries and veins.

Co-directors of the University’s Vascular Research Group Professor Andre van Rij and Associate Professor Greg Jones led the New Zealand arm of the major study, which involved over 40,000 people across a dozen countries.

The findings from the Iceland-led genome-wide association scan study have just been published in the prestigious journal Nature Genetics.

Dr Jones says knowledge of the new genetic marker will help better identify people at increased risk of AAA, which is an often undiagnosed and deadly condition found in seven per cent of New Zealand men over the age of 60.

The disease involves the large blood vessel that supplies blood to the abdomen, pelvis, and legs becoming abnormally large or ballooning outward. If the aneurysm ruptures between 40-80% of patients will die of the condition.

“In combination with other genetic risk factors for AAA that are already known, several of which we were involved in discovering, this finding will aid efforts to pinpoint people at greatest risk and allow for earlier interventions,” Dr Jones says.

The research involved scanning the genetic make-up of patients with AAA and other vascular diseases and comparing the results with those of similar but healthy individuals.

“With our international colleagues we have shown that individuals with a common variant in a gene known as DAB2IP have a significantly increased risk of developing AAA.

“Interestingly, we also found this genetic marker was associated with a similarly heightened risk of suffering early-onset heart attacks, peripheral arterial disease and pulmonary embolisms.”

Dr Jones says the increased risk was found to be separate to non-genetic risk factors such as smoking, bad cholesterol, obesity, type 2 diabetes and high blood pressure.

“This means that people with this genetic variant who also have any or all of those risk factors are more likely to develop AAA and other vascular diseases.”

The findings also add to a growing body of evidence challenging traditional thinking that diseases of the arteries and of the veins are quite separate disorders, he says.

“The variant’s increased risk for several arterial diseases and for pulmonary embolism, which is a vein-related disease, suggests that common underlying physiological factors are at work.”

Unravelling the mechanisms involved could pave the way for new therapies for a range of vascular diseases, he says.

The Otago researchers’ contributions to the study included screening the list of possible candidate genes that were initially identified and later performing an independent analysis for the reported association with the DAB2IP gene through their own genome-wide association scan.

Dr Jones says a key factor in New Zealand’s successful contribution to the study has been the near-universal willingness of Otago and Southland AAA patients to take part in research efforts.

“We contributed the largest group of these cases for the international study and are very grateful for these patients’ support.”

The research was supported by a programme grant from the Health Research Council of New Zealand.

ENDS