N Engl J Med 2018 11 10;379(22):2131-2139. Epub 2018 Oct 10.
From Harvard Medical School (K.S., C.E., I.S.K., J.L., A.T.M., D.A.S.), Brigham and Women's Hospital (J.L.), and Massachusetts General Hospital (D.A.S.) - all in Boston; the National Institutes of Health Clinical Center (D.R.A., W.A.G., J.J.M., C.J.T.) and the National Human Genome Research Institute (A.L.W.), Bethesda, and the University of Maryland, College Park (A.M.C.-J., B.K., L.P.) - all in Maryland; Baylor College of Medicine, Houston (C.A.B., H.J.B., C.M.E., B.H.L., X.L., M.F.W., S.Y.); Stanford University, Stanford (J.A.B., C.R., M.T.W., E.A.A.), and the University of California, Los Angeles, Los Angeles (S.F.N., C.G.S.P.) - both in California; Vanderbilt University, Nashville (R.H., J.A.P.); HudsonAlpha Institute for Biotechnology, Huntsville, AL (H.J.J., E.A.W.); Oregon Health and Science University, Portland (D.M.K.); the Pacific Northwest National Laboratory, Richland, WA (T.O.M.); the University of Oregon, Eugene (J.H.P., M.W.); and Duke University, Durham, NC (V.S., N.M.W.).
Background: Many patients remain without a diagnosis despite extensive medical evaluation. The Undiagnosed Diseases Network (UDN) was established to apply a multidisciplinary model in the evaluation of the most challenging cases and to identify the biologic characteristics of newly discovered diseases. The UDN, which is funded by the National Institutes of Health, was formed in 2014 as a network of seven clinical sites, two sequencing cores, and a coordinating center. Later, a central biorepository, a metabolomics core, and a model organisms screening center were added.
Methods: We evaluated patients who were referred to the UDN over a period of 20 months. The patients were required to have an undiagnosed condition despite thorough evaluation by a health care provider. We determined the rate of diagnosis among patients who subsequently had a complete evaluation, and we observed the effect of diagnosis on medical care.
Results: A total of 1519 patients (53% female) were referred to the UDN, of whom 601 (40%) were accepted for evaluation. Of the accepted patients, 192 (32%) had previously undergone exome sequencing. Symptoms were neurologic in 40% of the applicants, musculoskeletal in 10%, immunologic in 7%, gastrointestinal in 7%, and rheumatologic in 6%. Of the 382 patients who had a complete evaluation, 132 received a diagnosis, yielding a rate of diagnosis of 35%. A total of 15 diagnoses (11%) were made by clinical review alone, and 98 (74%) were made by exome or genome sequencing. Of the diagnoses, 21% led to recommendations regarding changes in therapy, 37% led to changes in diagnostic testing, and 36% led to variant-specific genetic counseling. We defined 31 new syndromes.
Conclusions: The UDN established a diagnosis in 132 of the 382 patients who had a complete evaluation, yielding a rate of diagnosis of 35%. (Funded by the National Institutes of Health Common Fund.).