AUG 21, 2013 12:00 PM PDT

Genetics of Coronary Artery Disease

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  • President, Chief Executive Officer and Chief Scientific Officer, Professor of Medicine, Director, Ruddy Canadian Cardiovascular Genetics Centre, University of Ottawa Heart Institute
      Robert Roberts is the President and CEO of the University of Ottawa Heart Institute and founding Director of The Ruddy Canadian Cardiovascular Genetics Centre. He received his M.D. from Dalhousie University and completed his residency in Internal Medicine and Fellowship in Cardiology at the University of Toronto. Funded by a Canadian Heart Foundation Scholarship, he pursued research in heart disease and in 1982 became Chief of Cardiology at Baylor College of Medicine in Houston, Texas. As a cardiologist, educator and scientist, he developed the MCBK Test which has been used to diagnose heart attacks for the past three decades. Dr. Roberts' research led him to molecular biology and genetics, during which time he discovered many genes responsible for heart disease. Dr. Roberts is generally regarded as one of the founders of molecular cardiology. Dr Roberts has had a distinguished and prolific career as a Cardiologist, Educator and Scientist having published over 850 scientific articles and received many awards including the 2012 Research Achievement Award from the Canadian Cardiovascular Society; the 2012 Distinguished Fellowship Award from the International Academy of Cardiology; the McLaughlin Medal from the Royal Society of Canada and the Albrecht Fleckenstein Memorial Award from the International Academy of Cardiology in 2008; Citation for Highly Cited Researcher from ISI Thomson Scientific in 2002; and the Distinguished Scientist Award from the American College of Cardiology in 1998.


    Susceptibility to coronary artery disease (CAD) is claimed to be 40% to 60% inherited, but until recently genetic risk factors predisposing to CAD have been elusive. Comprehensive prevention of CAD requires manipulation of genetic risk. The availability of microarrays of single-nucleotide polymorphisms enabling genome-wide association studies (GWAS) led to the discovery of 50 genetic risk variants for CAD. Surprisingly, 35 risk variants mediate their risk through unknown mechanisms, with only 17 associating with hypertension or lipids. Thus, there are several mechanisms contributing to the pathogenesis of CAD yet to be elucidated. The first risk variant discovered by GWAS was 9p21.3, which occurs in 75% of all populations except African, with a mean increased risk of 25% per copy. Of the 50 variants for CAD, the increased risk varies from 6% to 92% with a mean increased risk of 18%, occurring on average in 47% of the population. The maximum number of risk alleles per individual would be 100. In the CARDIoGRAM (Coronary Artery Disease Genome-wide Replication and Meta Analysis) study of 23 variants, the average per individual was 17, the minimum 7, and the maximum 37. The top 10th percentile has an odds ratio of 1.88 and the lowest percentile an odds ratio of 0.55. Routine genetic screening is unlikely until management is improved by genetic testing. Risk variants should provide pathophysiological insights and targets for novel therapy. While risk variants are less potent predictors of CAD, compared with biomarkers, they have the advantage of not changing in one's lifetime and are unaffected by diet, sex, age, or medication.

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