When the history of medicine in the late 20th Century and early 21st Century is written, one of the key figures and greatest contributors will be a native Chicagoan who was not even a physician. That man was James Watson, who earned his place in the annals of medicine as a molecular biologist and scientific visionary. In 1953, Watson along with Francis Crick and two less heralded scientists, Rosalind Franklin and Maurice Wilkins, discovered the DNA double helix, a discovery that provided the avenue for the current genetics revolution in medicine.
Their work was the starting point for the worldwide effort to sequence the human genome, the Holy Grail of man’s unique genetic heritage. Translation of the human genome will change the practice of medicine more than the discovery of the microscope, anesthesia or antibiotics. Physicians will eventually be able to practice medicine by tailoring care for each individual personally according to their genetic profile, something past generations of physicians could not have imagined.
More than a half-century after his momentous discovery, Watson was involved in another step in the genetics revolution. Recently, he was presented with a custom-made DVD, which took two months and $2 million to produce. The DVD contained virtually his entire personal genome sequence and even at that cost was truly a bargain because it was produced with new technology that afforded the cheapest, quickest complete human gene sequencing to date. By comparison, the Government’s Human Genome Project’s first reference genome, released less than five years ago, took over a decade and cost $3 billion to complete. Current advances in DNA testing and computer chip development will soon bring the cost of human genome identification down to a fraction of the cost of Watson’s and will make the sequencing available in a matter of days.
Meanwhile, simple genetic tests, identifying small fractions of the entire genome, are becoming available for use in the physician’s office. These tests have the theoretical ability to predict specifically which patients are likely to respond to different medications and what doses are most effective. In fact, the first widespread application of personalized genetics in clinical cardiology is now becoming a reality.
For decades, physicians had to prescribe a common blood thinner, warfarin (also known as coumadin), essentially on a trial-and-error basis. There was no alternative to this guesswork and the practice resulted in bleeding complications so frequently that for years warfarin has been among the top ten drugs causing adverse reactions in the United States. According to death certificates, in 2003 and 2004, it ranked first in number of deaths from therapeutic drugs causing adverse effects.
Now a breakthrough may have occurred. Last week, FDA officials suggested that doctors prescribing warfarin consider performing a recently discovered test identifying several genes in patients they intend to treat. The genes involved are responsible for the metabolism of warfarin and determine what dose of medicine the patient should receive. Formal studies of the role of gene testing for warfarin therapy must still be performed and questions of costs remain, but this genetic profiling is likely to become routine for all patients receiving warfarin within the next decade.
Genetics is changing the practice of other specialties besides cardiology. Researchers have identified genes associated with higher risks of developing breast and ovarian cancer as well as malignancies of the gastrointestinal tract. Based on genetic profiles, oncologists are creating strategies for early diagnosis and treatment of these tumors. Reproductive medicine and in vitro fertilization will benefit from improvements in genetic profiling. On the other end of life, researchers will soon understand more about the genetic mutations involved in the aging process and Alzheimer’s Disease.
One of medicine’s great 20th Century clinicians, William Bean, once wrote, “The one mark of maturity, especially in a physician, and perhaps it is even rarer in a scientist, is the capacity to deal with uncertainty.” Though he knew nothing of the human genome, Bean understood that uncertainty was an inevitable part of medical practice. There would always be things that would remain unknown to medical science. If he were alive today, he’d tip his hat to James Watson, who, though he never cared for a single patient, was responsible for eliminating a bit of the uncertainty of medical practice through the discovery of the double helix and his work with the human genome.
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