Source
From the 1NIH Undiagnosed Diseases Program; 2Office of the Clinical Director, National Human Genome Research Institute; 3Medical Genetics Branch, National Human Genome Research Institute; 4NIH Clinical Center; 5Department of Neurology, Children's National Medical Center, Washington, DC; 6Neurogenetics Branch, National Institute of Neurological Disorders and Stroke; 7Office of Rare Diseases Research, Office of the Director; 8Social and Behavioral Research Branch, and 9NIH Intramural Sequencing Center, National Human Genome Research Institute, NIH, Bethesda, Maryland.
Abstract
PURPOSE:
This report describes the National Institutes of Health Undiagnosed Diseases Program, details the Program's application of genomic technology to establish diagnoses, and details the Program's success rate during its first 2 years.
METHODS:
Each accepted study participant was extensively phenotyped. A subset of participants and selected family members (29 patients and 78 unaffected family members) was subjected to an integrated set of genomic analyses including high-density single-nucleotide polymorphism arrays and whole exome or genome analysis.
RESULTS:
Of 1191 medical records reviewed, 326 patients were accepted and 160 were admitted directly to the National Institutes of Health Clinical Center on the Undiagnosed Diseases Program service. Of those, 47% were children, 55% were females, and 53% had neurologic disorders. Diagnoses were reached on 39 participants (24%) on clinical, biochemical, pathologic, or molecular grounds; 21 diagnoses involved rare or ultrarare diseases. Three disorders were diagnosed based on single-nucleotide polymorphism array analysis and three others using whole exome sequencing and filtering of variants. Two new disorders were discovered. Analysis of the single-nucleotide polymorphism array study cohort revealed that large stretches of homozygosity were more common in affected participants relative to controls.
CONCLUSIONS:
The National Institutes of Health Undiagnosed Diseases Program addresses an unmet need, i.e., the diagnosis of patients with complex, multisystem disorders. It may serve as a model for the clinical application of emerging genomic technologies and is providing insights into the characteristics of diseases that remain undiagnosed after extensive clinical workup.