By Medical Discovery News
July 28, 2012
It took 10 years and over $3 billion to sequence the first human genome. Now, more than three dozen companies will soon offer personal genome sequencing for less than $1,000. So anyone can mail a tissue sample and get a USB drive with their DNA sequence in return. The problem is a person can’t do much with all that information just yet.
One of the great promises of this technology is that one day, doctors will routinely practice personalized medicine. Genome sequencing may eventually identify a person’s susceptibility to developing certain diseases, predict how a disease will progress, and how the person will respond to different types of treatments.
Certain genetic disorders are easily predictable based on the inheritance of simple genetic variances. For example, inheriting two hemoglobin genetic mutations can cause sickle cell disease. Other examples of genetic diseases easily identified by DNA sequencing include muscular dystrophy, chronic myelogenous leukemia, hemophilia, and Huntington’s disease, which are among an estimated 4,000 single gene disorders.
Genome sequencing will likely identify more of these relatively simple genetic disorders involving one or a few genes. However, the majority of diseases are going to be much more complex, and involve multiple genes with products that may interact or combine to influence disease development.
As a result, the potential of genome sequencing will be limited until scientists are able to further understand how diseases develop. For years scientists have studied identical twins to determine whether genes or the environment have a greater impact on disease development. Surprisingly, twins with the same genomes, socioeconomic background, childhood environment, upbringing, and environmental exposures usually do not die of the same thing.
This shows that any set of risk predictors is not defined well enough to guarantee a person’s health destiny. In time, geneticists may be able to define these genetic risk factors, making them more reliable. But even when a genetic test clears someone of the risk for certain diseases, it is not a free pass because environment and lifestyle choices are critical factors.
It’s possible that as geneticists better understand the role of specific genes on human health, genome sequencing may be a valuable tool for guiding physicians on how to treat diseases. Since people respond differently to treatments and drugs, this information may help doctors personalize treatment plans so that they are safe and effective for each individual.
Even though genome sequencing is becoming affordable, there’s little a person can do with the information right now. Also, consider how insurance companies or potential employers could misuse such private information. Always ask about a company’s privacy policy before deciding to plunk down the money for a test.
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Pamela K. Bond 