Grand Rounds: Genomic Medicine: Hope, Hype and Reality

June 10, 2009

Grand Rounds ImageKristen Lee MD

Please also see the clinical vignette presented before Grand Rounds on the 13th of May.

The Medical Grand Rounds lecture on May 13, 2009 titled “ Genomic Medicine: Hope, Hype and Reality” was presented by Dr. Robert Desnick, M.D., Ph. D. Professor and Chair of the Department of Genetics and Genomic Sciences at the Mount Sinai School of Medicine.

Dr. Desnick began with therapeutic revolutions in the 20th century which include the discovery of antibiotics, vaccines, transplant medicine, laporoscopic and robotic surgeries and finally, genome based medicine. Gene discovery has enabled us to elucidate the pathophysiology of diseases, predict and prevent diseases and discover new interventions and therapies. These have collectively allowed us to provide individualized or “personalized medicine”- which is the hope of genome based medicine.

For example, in common diseases such as allergy, asthma, cancers, coronary artery disease, obstructive lung disease, diabetes,…etc, the goal is to identify predisposing genes through methods of linkage analysis and genome wide association studies in order to understand the pathophysiology and ultimately, provide new and improved therapies. Some successes in this area include the identification of a gene variant for Crohn’s disease that involves bacterial recognition and the hope of finding a new target for therapy.

Some early successes have stimulated many genome wide studies for common disease and high expectations for identifying susceptible genes. This is the hype. Proponents offer medicine that is predictive, preventive and “personalized.” Many companies now offer genome based risk predictions where you can “Know thyself” and have your genotype for certain diseases or your entire genome sequenced for anywhere between $399 to $350,000! The question and ethical dilemma that arises from all this information is whether knowing your risk through gene sequencing is really predictive or just premature.

The reality is that genome based medicine is in its infancy, and few common disease susceptibility genes have been identified that will actually impact medical practice. Through these analyses, family history seems to trump everything and has a high predictive value. However, successes in cancer research and pharmocogenetics will predict survival, relapse, and optimal therapy with minimal side effects. Examples include gene expression-based survival prediction in lung adenocarcinoma and prediction of warfarin metabolism sensitivity based on the genes for cytochrome P450/CYP 2C9 and VKORC1. As medical professionals, we may or may not embrace the future of genome-based medicine, but we can at least be prepared to advise the patients who will.

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