October 25, 2018
Not every doctor is an adroit diagnostician—and even those who are will admit to being stumped occasionally by a patient’s symptoms. Now, there is help, even for the hardest cases, from the Undiagnosed Diseases Network—a program created by the National Institutes of Health in 2012.
The program, which first was conceived back in 2008, now depends on a network of collaborative healthcare institutions nationwide—and cross-disciplinary physicians at those institutions—including Baylor College of Medicine, Brigham and Women’s Hospital, Boston Children’s Hospital, Massachusetts General Hospital, Children’s Hospital at Philadelphia and University of Pennsylvania, Duke University and Columbia University, Harvard Medical School and University of Alabama at Birmingham, Mayo Clinic, Stanford Medicine, UCLA, University of Miami School of Medicine, University of Utah, University of Washington School of Medicine and Seattle Children’s Hospital, Vanderbilt University Medical Center, and Washington University in St. Louis.
Through the efforts of the network, more than 100 patients afflicted by mysterious illnesses have been diagnosed to date—and 31 new diseases have been identified.
“Our goal is to take on the hardest cases in medicine — to find patients and families with conditions that no one has been able to solve,” explained Euan Ashley, M.D., a professor of Medicine (Cardiology) at Stanford University, in a news release from the school. “We wanted to provide a place that these people could come, so the Undiagnosed Diseases Network came together to try to answer that need.”
The group, which comprises hundred of doctors, has so far sleuthed out 132 of 382 previously unknown ailments —or roughly 35%.
Some of these patients had been waiting decades to put a name to their illness. They tell us how much of a relief it is simply to know what they were up against,” Ashley said. But what’s most exciting, he said, was that for 80% of the network’s diagnoses, they distilled actionable information, such as changes to patient therapy, adjustments to future diagnostic testing and recommendations for family screening.
“Our findings underscore the impact that establishing a clear diagnosis can have on clinical decision-making for previously undiagnosed patients,” said Kimberly Splinter, associate director Research Operations for the network’s Coordinating Center and a genetic counselor at Harvard Medical School. “We hope that the results of this analysis will provide a compelling case for adopting some of the network’s diagnostic approaches more broadly in an attempt to clarify diagnoses and refine treatment for patients with rare conditions.”
Splinter is the lead author (and Ashley is the senior author) of a paper describing the study that was published online on October 11 in The New England Journal of Medicine.
Of the 1,519 applications from patients that the network received when it was formed, 601 were accepted based on the likelihood that the network would be able to help them, given their past medical records and available data. Now, Ashley and the team of physicians have seen more than half of those patients, combining traditional medicine with increasingly cutting-edge diagnostic tests. The network continues to accept applications.
“We do this Sherlock Holmes-like detective work-up by carefully observing, gathering information and asking pointed questions, but we’re also pairing that with the most advanced genomic technologies to try to solve their case,” Ashley said.
Every patient had their genome sequenced, even those whose genomes had been previously sequenced. The field of genetic and genomic testing moves so quickly, Ashley explained, that even patients who’ve had their genome sequenced six months ago benefit from another look. In coordination with genome sequencing, the physicians looked at patients’ RNA profiles, analyzing precursor molecules to the proteins found in their bodies. They also broke down a collection of molecules called metabolites, which form as a product of metabolism and can hint at where metabolic processes go wrong.
“Some cases are solved simply because we know more today than we did a year ago,” Ashley said.
Among those diagnosed, most exhibited rare versions of known diseases, broadening the symptomatic information doctors can look for when evaluating patients for those particular diseases in the future. But in 31 patients, the network identified previously unknown syndromes.
A particularly interesting case study is provided by co-author Matthew Wheeler, M.D., assistant professor of Medicine at Stanford and executive director of the Stanford Center for Undiagnosed Diseases. The case involved a patient whom the network followed for multiple years. The patient had mysterious and life-threatening episodes of something called lactic acidosis, a dangerous buildup of lactic acid in the body.
“It’s sort of like an extreme version of when you exercise intensely, and you feel that burn from the lactate buildup — only it’s your whole body that feels that way,” Wheeler said. “Lactic acidosis can also cause your acid-base balance to be out of whack, and when people have severe acid-base disturbances, they’re at high risk for arrhythmia or death.”
It wasn’t clear why the patient was experiencing these symptoms, which seemed to be prompted by a cold or flu. After giving the patient the full gamut of tests and analyzing sequencing information, a team of Stanford scientists found the culprit: a single mutation in the gene ATP5F1D, which is involved in the function of mitochondria, the cell’s powerhouse.
The genetic oddity and symptoms had never been classified together officially, but from connections within the network and in some instances word of mouth, the scientists found that other doctors around the world had patients plagued by this syndrome. In verifying that the mutation causes the syndrome—called mitochondrial complex V deficiency, nuclear type 5 — network collaborators on the study developed animal models to show causality.
“This is a new type of scientific odyssey,” Ashley said. “We’re learning about biology in a way that could help not just one family, but potentially dozens, even hundreds, of families who suffer that same rare condition. That’s the biggest benefit of this network effect — the impact of identifying one patient’s disease could end up being global.”
Even the patients who did not receive a diagnosis benefit from knowing that a team continues to investigate their conditions and that the future may hold an answer even if the present does not.
“We’ve had patients tell us that just knowing that there is a team looking into their condition, that there is someone in the world who has not given up on them, scientists continuing to keep an eye on the literature — that provides hope,” Ashley said.
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