3 months ago our family dog got sick. Her liver was very inflamed. The evaluation revealed copper deposits in her liver. This was likely due to a genetic defect – very common in several breeds in dogs, but not common in hers. Despite efforts to remove the copper with medication, the damage was too severe, and we lost her about a month ago.
This prompted some research into her family history – one “cousin” died from liver issues, but it was not known if it was copper related. There is a blood test that can see if a dog had the “copper” gene and my wife and I started discussing what we would have done differently if we had known.
Since cloning the human genome, we have identified genes and mutations associated with cancer, drug sensitivities and the risk of other chronic conditions. We have also identified mutations that may not have any impact on health, and others that the impact is unclear or unknown.
Using that genetic knowledge to direct diagnosis and treatment is called personalized or precision medicine
. It was mentioned in the Federal Budget for 2016
and the National Institutes of Health
is dedicating significant research money to it. There have been several direct to consumer companies offering to read your DNA and tell you what diseases you are at risk for.
How is this done and what can you really learn?
Precision Medicine assumes that by running a person’s DNA code you will get results that shows what diseases you are likely to get – heart disease, diabetes, cancer, etc. For those diseases you already have, it can tell you which medications are most likely to be effective. Plans can then be developed to treat illness and recommend screening programs based on one’s DNA code – offering medications with the best chance of success to those with the proper codes and not giving them to people who are not likely to respond or be at increased risk of toxicity.
There are already examples of this in use today. We avoid medications in people with certain genetic markers because they are more susceptible to side effects (people may be more or less sensitive to certain blood thinners based on their DNA). Many cancers, from lung to breast to lymphoma and leukemia have genetic markers run to see what treatments are likely to work. Perhaps the most famous use of genetic testing determining treatment is Angelina Jolie
. She tested positive for the BRCA1 gene greatly increasing her risk of breast and ovarian cancer. She then elected to have mastectomies and her ovaries and uterus removed before any cancer developed.
Genetic based diagnosis and treatment has the potential to change the way we evaluate risk and treatment. However, checklist testing and treatment is not personal. Blind application of data to a person without context (history) reduces medical care to algorithms and formula without the personalization it is supposed to offer. There is a social and ethical side to the use of genetic information that we are just beginning to understand, from privacy laws to insurance regulation to job security. Would you hire someone you knew had an increased risk of and potentially expensive illness if you were responsible for paying for their care? Would you marry someone knowing their illness potential? Have children? These are all issues that need to be sorted out as we move into this new paradigm for healthcare.
Most importantly, people need good information on what their tests mean. Many of the kits available now report mutations that aren’t clearly associated with disease. The FDA ordered one company to stop selling its test and services
due to non-compliance with testing regulations. They have since started selling a very specific test for a single condition, but not a general DNA analysis. The next age of primary care will involve helping people curate and collate their genetic information.
Do I worry that the genetic classification of diagnosis and treatment will make me obsolete?
To the contrary, I think it can make me better at what I do. I already strive to get to know my patients, understand how health or lack thereof fits in the rest of their life. We discuss risk for future disease, concerns about hereditary and what medicines are best for them. That is personalized medicine. Getting to know my patients at the genetic level can only strengthen that bond. Using the information we get from genetic testing and putting it in the context of the person sitting across from me is how we put the Personal in Personalized Medicine.
The path to wellness begins with a proper diagnosis