Rare Disorders ID'd by NIH Undiagnosed Diseases Program
Integrated high-density SNP arrays, whole exome or genome analyses used to aid diagnosis
THURSDAY, Oct. 13 (HealthDay News) -- The extensive application of genomic technology under the U.S. National Institutes of Health Undiagnosed Diseases Program (NIH-UDP) helps diagnose complex and rare multisystem disorders, according to a report published online Sept. 26 in Genetics in Medicine.
William A. Gahl, M.D., Ph.D., from the National Human Genome Research Institute in Bethesda, Md., and colleagues evaluated the NIH UDP's success rate during its first two years, and detailed its use of genomic technology to diagnose patients with complex disorders. Each patient with an undiagnosed disorder under the NIH-UDP was phenotyped in detail. In addition, 29 participants and their 78 selected, unaffected family members underwent an integrated set of genomic analyses, including high-density single-nucleotide polymorphism (SNP) arrays and whole exome or genome analysis.
The authors found that the NIH-UDP reviewed 1,191 medical records in its first two years, of which 326 patients were accepted, and 160 directly admitted under the NIH-UDP service. These included 47 percent children, 53 percent females, and 53 percent neurologic disorders. Of the patients admitted under NIH-UDP, 24 percent (39 patients) were diagnosed on clinical, biochemical, pathologic, or molecular grounds with 21 diagnoses of rare or ultrarare diseases. SNP array analysis formed the basis of three diagnoses, and three others were based on whole exome sequencing and filtering of variants. The NIH-UDP also discovered two new disorders. Analysis of the SNP array group showed that affected participants more commonly had large stretches of homozygosity compared to controls.
"The NIH UDP addresses an unmet need, i.e., the diagnosis of patients with complex, multisystem disorders," the authors write.