Rare Diseases: From Newborns to Nonagenarians

Part 1 of an Interview With Marshall L. Summar, MD

Laura A. Stokowski, RN, MS; Marshall L. Summar, MD


April 23, 2014

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Editor's Note:
A disease is considered rare in the United States if it affects fewer than 200,000 people. Collectively, however, rare diseases are believed to affect 1 in 10 people, and they can present at any stage of life.

It's impossible for front line clinicians to keep up to date on the thousands of known rare diseases, so they depend on experts such as Marshall L. Summar, MD, Chief of the Division of Genetics and Metabolism at Children's National Medical Center in Washington, DC, to help zero in on the possible cause when a patient -- whether it is a newborn or a nonagenarian -- presents with symptoms that suggest a rare disease.

Medscape recently spoke with Dr. Summar about advances in the diagnosis and management of rare diseases, and how clinicians can approach these patients and access the assistance of rare disease experts -- medicine's "puzzle-solvers."

Read Part 2 of this interview here.

Marshall L. Summar, MD

Greatest Recent Advances in Rare Diseases

Medscape: You have worked in the field for a long time. What advances do you believe are responsible for having the greatest impact on progress in identifying and treating inborn errors of metabolism (IEMs) and other rare diseases?

Dr. Summar: First and foremost has been the expansion in newborn screening, from the very good Guthrie test to the more expanded tandem mass spectroscopy test. That has had a huge impact on the field from the fatty acid oxidation disorders to the organic acidemias, and even some of the urea cycle disorders. It has allowed us to detect patients presymptomatically. In the past, we wouldn't have seen these children until they were very sick.

The second thing that has had a huge impact on the field is the development of consensus treatment guidelines. We have developed consensus treatment guidelines for urea cycle disorders; other groups have done so for the organic acidemias, and guidelines are coming along for the fatty acid oxidation disorders.

Gathering the best practices from all the different groups and bringing those together has been a real boon to the field. In the urea cycle field alone, we sat down back in 2001 and came up with a consensus protocol. We can now show in our longitudinal study that those guidelines have had an impact on survival as well as on developmental outcomes, so that is obviously a big boon for the field.

The third major advance is the new pharmaceuticals that we have. We have compounds for treating disorders that we have never had before. In the field of IEMs, we still have a long way to go. Drugs to treat lysosomal storage disorders have had the most development, but we are making progress in the intermediary metabolism field, too.

Finally, something that is every bit as important is our educational efforts -- getting the word out on what these patients look like. Once upon a time, physicians didn't pay a lot of attention to these diseases because it was assumed that they weren't treatable. It was best to devote your brain cells to remembering other things. Now that we have shown that these kids do survive -- that they can do pretty well, and even have some good outcomes -- I think physicians are starting to think more about them. We do a lot of education around early detection, early diagnosis, and response, and my experience has been that these efforts have been a tremendous help as well.

Medscape: A recent study showed that clinicians felt that they did not have enough education in the rare diseases field.[1] Is anything specific being done to educate students more about rare diseases?

Dr. Summar: Most of the efforts have been more local than national. Centers that have a lot of rare disease experts are going out to the local hospitals in their communities and teaching about rare diseases. It's very difficult. There are more than 7300 rare diseases, and each one has its own fascinating and in-depth profile. It is impossible to teach students about all of them during training.

Instead, I think we need more emphasis on teaching the right approach to a patient who might have a rare disease. As opposed to memorizing a set of facts and figures about any one disease, how do you approach the ill newborn and take into account the possibility of a rare disease? What laboratory tests can you use as screening tools? What things should you think about? When should you try to react quickly to what is going on with the patient? I think teaching that approach will be more effective.


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