deCODE Complete

Genetic factors have a recognized impact on the development of Abdominal Aortic Aneurysms, with 15-20% of affected individuals reporting a family history of the condition.

The deCODE Complete Scan analyzes your patients’ DNA and provides you with a personalized interpretation of their genetic risk for developing Abdominal Aortic Aneurysm.

Genetic factors impact the risk of developing Abdominal Aortic Aneurysms – Knowing your patients’ genetic risk is knowing more about their overall risk

Abdominal aortic aneurysms are bulges in weakened sections of the aorta

The aorta is the body´s largest artery, carrying blood from the heart to smaller branch arteries. An aortic aneurysm is an abnormal weakening of parts of the aorta wall. The pressure from blood flowing through the aorta can cause the weakened part to bulge. An aneurysm can stretch the aorta wall to the extent that it finally bursts or ruptures. A ruptured aneurysm can cause severe internal bleeding and leads to death in over 65% of instances. Fortunately, especially when diagnosed early, an aortic aneurysm can be treated, or even cured, with highly effective and safe treatments.

The two main types of aortic aneurysms are abdominal and thoracic

There are two main types of aortic aneurysms, thoracic and abdominal, depending on which part of the aorta is affected; the upper part that traverses the chest (thoracic aortic aneurysm or TAA) or the lower part that traverses the abdomen (abdominal aortic aneurysm or AAA). About three in four of all aortic aneurysms are AAA.

Most AAAs are without symptoms until rupture or near rupture

In most cases individuals experience no symptoms at all or only vague symptoms of AAA until the aneurysm is near rupture or ruptures. Therefore the true prevalence of AAA is not known, but it is estimated that 1.5% to 9% of men and 1% to 2% of women have this condition. AAA ruptures cause roughly 15,000 deaths every year in the United States.

Genetics contribute to the risk of developing AAA

Research suggests that AAA has a strong familial component. This indicates that there is an important genetic contribution to the risk of developing AAA. Our scientists at deCODE genetics have identified a common genetic variant on chromosome 9 that is associated with increased risk of AAA (Helgadottir et al, 2008). The same variant also increases the risk of Heart Attack in individuals of both European and Asian ancestry and Brain Aneurysm in European individuals.

deCODEhealth calculates your patients’ genetic risk for Abdominal Aortic Aneurysm

Several genetic variants have been identified that increase the risk of developing AAA. The number of variants included in the deCODEhealth Genetic Scan for each ethnic group are listed in the table below. These variants are used to provide a personalized interpretation of their genetic risk for developing AAA.

	Number of Variants Measured
European ancestry	3

At present, the necessary scientific information to interpret the genetic risk for individuals of other ethnicities is not available. This information will be added as soon as it becomes available and we are assured of its quality.

Who is at increased risk for AAA?

Although the ultimate causes for AAA are still unclear, the known risk factors are:

• Age and gender: AAA is most commonly encountered in older men. The condition is 2-5 times more common in men than women and the incidence increases with age in both sexes. In populations over age 60, estimates of prevalence range from 2% to 8%. AAA is uncommon in both men and women younger than 50 years of age.
• Smoking: Smoking is the single most important environmental risk factor and the more people smoke, the greater the risk. This is probably because the underlying cause for most AAA is atherosclerosis of the aorta, which is exacerbated by smoking. Research has shown that the prevalence of AAA in tobacco smokers is more than four times that of life-long non-smokers.
• Other cardiovascular risk factors: Some cardiovascular risk factors such as high blood pressure and abnormal cholesterol levels have been associated with AAA, whereas others, such as diabetes, have not.
• Ethnicity: AAA is diagnosed less frequently in Asians and African-Americans than individuals of European descent.
• Genetics: Genetic factors have a recognized impact on the development of AAA, with 15-20% of affected individuals reporting a family history of the condition. The lifetime risk of AAA in a first degree relative (parent, child or sibling) of a patient with AAA is 11-28% or 3-7 times that of the general population (with a lifetime risk of 4%).

Not smoking is the single most important strategy to prevent AAA

The single most important prevention strategy is not to smoke and if smoking, to stop. A healthy lifestyle in general is recommended, including regular exercise and maintenance of a normal weight.

The American College of Cardiology recommends a screening abdominal aortic ultrasound for men 60 years of age or older who are either siblings of AAA patients or have parents with AAA as well as for male smokers (current and former smokers) between 65 and 75 years of age.

When diagnosed early, an AAA can be successfully treated

In all patients with recognized Abdominal Aortic Aneurysm, blood pressure and cholesterol control is recommended and generally, surgical repair is planned for all aneurysms which are 5.5 centimeters (2.2 inches) and larger as well as all symptomatic AAA regardless of diameter. Urgency of surgical repair depends on the risk of rupture.

More information

If concerned about AAA, their doctor is their best resource. Additional information about AAA can be found on these web sites:

• American Heart Association
• American Academy of Family Physicians
• MedlinePlus – Trusted Health Information for You
• National Heart Lung and Blood Institute

Scientific references

1. Diehm N, Dick F, Schaffner T, Schmidli J, Kalka C, Di Santo S, Voelzmann J, Baumgartner I. Novel insight into the pathobiology of abdominal aortic aneurysm and potential future treatment concepts. Prog Cardiovasc Dis. 2007 Nov-Dec;50(3):209-17. Review.
2. Helgadottir A, Thorleifsson G, Magnusson KP, et al. The same sequence variant on 9p21 associates with myocardial infarction, abdominal aortic aneurysm and intracranial aneurysm. Nat Genet. 2008 Feb;40(2):217-24.
3. Iribarren C, Darbinian JA, Go AS, Fireman BH, Lee CD, Grey DP.Traditional and novel risk factors for clinically diagnosed abdominal aortic aneurysm: the Kaiser multiphasic health checkup cohort study. Ann Epidemiol. 2007 Sep;17(9):669-78.
4. Kuivaniemi H, Platsoucas CD, Tilson MD 3rd. Aortic aneurysms: an immune disease with a strong genetic component. Circulation. 2008 Jan 15;117(2):242-52. Review.
5. Sakalihasan N, Limet R, Defawe OD. Abdominal aortic aneurysm. Lancet. 2005 Apr 30-May 6;365(9470):1577-89. Review.

This content was last reviewed on February 16, 2012.