Molecular findings among patients referred for clinical whole-exome sequencing.

TitleMolecular findings among patients referred for clinical whole-exome sequencing.
Publication TypeJournal Article
Year of Publication2014
AuthorsYang, Y, Muzny, DM, Xia, F, Niu, Z, Person, R, Ding, Y, Ward, P, Braxton, A, Wang, M, Buhay, C, Veeraraghavan, N, Hawes, A, Chiang, T, Leduc, M, Beuten, J, Zhang, J, He, W, Scull, J, Willis, A, Landsverk, M, Craigen, WJ, Bekheirnia, MReza, Stray-Pedersen, A, Liu, P, Wen, S, Alcaraz, W, Cui, H, Walkiewicz, M, Reid, J, Bainbridge, M, Patel, A, Boerwinkle, E, Beaudet, AL, Lupski, JR, Plon, SE, Gibbs, RA, Eng, CM
Date Published2014 Nov 12
KeywordsAdolescent, Adult, Child, Child, Preschool, Exome, Female, Fetus, Genetic Diseases, Inborn, Genetic Testing, Genomics, Humans, Incidental Findings, Infant, Infant, Newborn, Male, Molecular Diagnostic Techniques, Mutation, Phenotype, Referral and Consultation, Sequence Analysis, DNA

IMPORTANCE: Clinical whole-exome sequencing is increasingly used for diagnostic evaluation of patients with suspected genetic disorders.OBJECTIVE: To perform clinical whole-exome sequencing and report (1) the rate of molecular diagnosis among phenotypic groups, (2) the spectrum of genetic alterations contributing to disease, and (3) the prevalence of medically actionable incidental findings such as FBN1 mutations causing Marfan syndrome.DESIGN, SETTING, AND PATIENTS: Observational study of 2000 consecutive patients with clinical whole-exome sequencing analyzed between June 2012 and August 2014. Whole-exome sequencing tests were performed at a clinical genetics laboratory in the United States. Results were reported by clinical molecular geneticists certified by the American Board of Medical Genetics and Genomics. Tests were ordered by the patient's physician. The patients were primarily pediatric (1756 [88%]; mean age, 6 years; 888 females [44%], 1101 males [55%], and 11 fetuses [1% gender unknown]), demonstrating diverse clinical manifestations most often including nervous system dysfunction such as developmental delay.MAIN OUTCOMES AND MEASURES: Whole-exome sequencing diagnosis rate overall and by phenotypic category, mode of inheritance, spectrum of genetic events, and reporting of incidental findings.RESULTS: A molecular diagnosis was reported for 504 patients (25.2%) with 58% of the diagnostic mutations not previously reported. Molecular diagnosis rates for each phenotypic category were 143/526 (27.2%; 95% CI, 23.5%-31.2%) for the neurological group, 282/1147 (24.6%; 95% CI, 22.1%-27.2%) for the neurological plus other organ systems group, 30/83 (36.1%; 95% CI, 26.1%-47.5%) for the specific neurological group, and 49/244 (20.1%; 95% CI, 15.6%-25.8%) for the nonneurological group. The Mendelian disease patterns of the 527 molecular diagnoses included 280 (53.1%) autosomal dominant, 181 (34.3%) autosomal recessive (including 5 with uniparental disomy), 65 (12.3%) X-linked, and 1 (0.2%) mitochondrial. Of 504 patients with a molecular diagnosis, 23 (4.6%) had blended phenotypes resulting from 2 single gene defects. About 30% of the positive cases harbored mutations in disease genes reported since 2011. There were 95 medically actionable incidental findings in genes unrelated to the phenotype but with immediate implications for management in 92 patients (4.6%), including 59 patients (3%) with mutations in genes recommended for reporting by the American College of Medical Genetics and Genomics.CONCLUSIONS AND RELEVANCE: Whole-exome sequencing provided a potential molecular diagnosis for 25% of a large cohort of patients referred for evaluation of suspected genetic conditions, including detection of rare genetic events and new mutations contributing to disease. The yield of whole-exome sequencing may offer advantages over traditional molecular diagnostic approaches in certain patients.

Alternate JournalJAMA
PubMed ID25326635
PubMed Central IDPMC4326249
Grant ListU54 HG006542 / HG / NHGRI NIH HHS / United States
U54 HD083092 / HD / NICHD NIH HHS / United States
U54 HG003273 / HG / NHGRI NIH HHS / United States
U01 HG006485 / HG / NHGRI NIH HHS / United States
K12 DK083014 / DK / NIDDK NIH HHS / United States
U01HG006485 / HG / NHGRI NIH HHS / United States
R01 NS058529 / NS / NINDS NIH HHS / United States

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