The National Institutes of Health (NIH) , a part of the U.S. Department of Health and Human Services , is the nation’s medical research agency. It is made up of 27 Institutes and Centers , each with a specific research agenda.

Of these, one center and one institute are the primary forces behind the NIH’s clinical site of the Undiagnosed Diseases Network (UDN): the NIH Clinical Center, which is the largest hospital in the world totally dedicated to clinical research, and the National Human Genome Research Institute (NHGRI). Many medical specialties from other NIH research centers and institutes also contribute their expertise, including endocrinology, immunology, oncology, dermatology, dentistry, cardiology and genetics, among the dozens of participating senior attending physicians.

Leading this UDN clinical site are the Clinical Director and Deputy Clinical Director of NHGRI, Drs. William Gahl and Cynthia Tifft. A longtime leader in the field of rare diseases, Dr. Gahl co-founded and directs the NIH’s Undiagnosed Diseases Program (UDP) , a precursor to the UDN. The UDP began as an intramural program in 2008 to focus on the most puzzling medical cases referred to the NIH Clinical Center by physicians across the nation. In 2009, Dr. Tifft added her expertise to the effort as director of the Pediatric UDP, coordinating the selection and clinical evaluation of children whose diagnoses have long eluded the medical community.

Building on the success of the UDP in diagnosing both known and new diseases, the NIH Common Fund announced in 2012 that it will provide $145 million over seven years to achieve the same type of cross-disciplinary approach to disease diagnosis in academic medical centers around the United States. Hence, the UDN was born. In addition to continuing their practice at the UDP, Drs. Gahl and Tifft now advise the entire network based on their experience and lessons learned.




NIH names new clinical sites in Undiagnosed Diseases Network 
July 1, 2014
NIH News

Hard cases: Investigating rare & tough diseases 
May 20, 2012
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Medical Detectives Find Their First New Disease 
February 2, 2011
New York Times

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February 18, 2009
New York Times

NIH Launches Undiagnosed Diseases Program
May 19, 2008
NIH News




The NIH is the largest source of funding for medical research in the world. More than 80% of the NIH’s budget goes to more than 300,000 research personnel at over 2,500 universities and research institutions. In addition, about 6,000 scientists work in NIH’s own Intramural Research laboratories, most of which are on the NIH main campus. [source: http://www.nih.gov/about/] The Undiagnosed Diseases Network incorporates both of these approaches—intramural funding to the UDP site of the UDN, and external funding to the other sites and cores.