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David Valle on the Johns Hopkins inHealth Initiative

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David Valle on the Johns Hopkins inHealth Initiative

Interviewed by Catherine Gara

David Valle on the Johns Hopkins inHealth Initiative

David Valle is director of the McKusick-Nathans Institute of Genetic Medicine. He works to discover the genetic causes of disease and is part of the Johns Hopkins inHealth steering committee.

What is Johns Hopkins inHealth?

VALLE: Johns Hopkins inHealth is a program developed by Johns Hopkins to enable a more individualized approach to patient care — and to improve our ability to keep people healthy in the first place. It brings together experts from a wide variety of fields to rethink today’s most pressing health care problems, find innovative solutions and then bring them to bear on the health of each individual patient. It’s our version of President Obama’s Precision Medicine Initiative.

How will this change the way we practice medicine? Why is it needed?

VALLE: A lot of medicine is still practiced as if “one size fits all.” For example, most adults are given the same drug dose regardless of their body mass. Weight is an obvious difference that we can easily measure, but now we also have the tools to analyze many other “invisible” qualities, like genes and biochemical signatures, that can influence outcomes just as much, if not more. We need to start taking these differences into account as we treat people.

What is the role of genetics in all of this?

VALLE: We are still very early in the process of understanding the human genome, but more is being discovered every day. We know that most genetic differences between people probably have no functional consequences and are therefore neutral in regards to health. Another, much smaller, set of genetic differences directly cause disease. A third set of differences are not causative on their own but do affect risk for disease; they can produce disease in combination with other risk variants and various environmental factors. As we learn more, we will be able to use these differences to subdivide patients into more homogeneous groups that share risk variants and environmental histories. This individualization will lead to better understanding of why individual patients get sick and how to tailor their therapy so that it is more effective with less risk of complications. An easy example of how genetic differences can influence treatment response is a genetic variant — present in about 5 percent of individuals — that confers sensitivity for a life-threatening complication for treatment with the anti-AIDs drug abacavir. Failure to test for this variant exposes the patient to a potentially fatal complication. 

Do you envision every baby having his or her genome sequenced at birth someday?

VALLE: Yes, but we’re not ready yet. There are many potential social pitfalls, like scaring people unnecessarily or prematurely when they learn they have a certain genetic predisposition. Thus, these changes in medical practice will have to be thought through carefully before we proceed, but I think it will be possible to minimize the risks and maximize the benefits.

What has to be developed in the long term to put individualized medicine into practice?

VALLE: We need to start collecting genetic information, including family histories, from more patients. We need to be rigorous in gathering patients’ clinical information — geneticists call this “phenotyping” — and their environmental information: everything from what sports they play to what toxins they might have been exposed to. We need to integrate all of the blood tests, medical images, biopsy results and treatments for every patient, and follow them to see if they are getting better or worse. Then, we have to develop the bioinformatics tools to store all of that information safely and code it in a way that can be analyzed meaningfully. Last but not least, we have to change education for doctors and patients so that they understand these new approaches and take advantage of them. These are all part of the Johns Hopkins inHealth mission.

What’s an example of a project designed to accomplish the goals of Johns Hopkins inHealth?

VALLE: There’s a very genetics-oriented project underway to better our treatment of patients with cystic fibrosis (CF). It’s led by Garry Cutting in the McKusick-Nathans Institute of Genetic Medicine. CF is a multisystem disease that is usually fatal by the age of 40. It’s caused by defects in a single gene, called CFTR, with nearly 2,000 mutations reported in that gene with a range of functional consequences. Cutting and his team have also shown that variation in several other genes around the genome influence how each individual CF patient responds to loss of CFTR function. Similarly, they have also identified key environmental variables that influence the severity and progression of CF. They are now trying to integrate this information to individualize the prognosis and treatment of each CF patient to provide the best quality and duration of life possible.