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Dharmadhikari AV, Ghosh R, Yuan B, Liu P, Dai H, Al Masri S, Scull J, Posey JE, Jiang AH, He W, Vetrini F, Braxton AA, Ward P, Chiang T, Qu C, Gu S, Shaw CA, Smith JL, Lalani S, Stankiewicz P, Cheung SW, Bacino CA, Patel A, Breman AM, Wang X, Meng L, Xiao R, Xia F, Muzny D, Gibbs RA, Beaudet AL, Eng CM, Lupski JR, Yang Y, Bi W. Copy number variant and runs of homozygosity detection by microarrays enabled more precise molecular diagnoses in 11,020 clinical exome cases. Genome Med 2019; 11:30. [PMID: 31101064 PMCID: PMC6525387 DOI: 10.1186/s13073-019-0639-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 04/09/2019] [Indexed: 02/02/2023] Open
Abstract
Background Exome sequencing (ES) has been successfully applied in clinical detection of single nucleotide variants (SNVs) and small indels. However, identification of copy number variants (CNVs) using ES data remains challenging. The purpose of this study is to understand the contribution of CNVs and copy neutral runs of homozygosity (ROH) in molecular diagnosis of patients referred for ES. Methods In a cohort of 11,020 consecutive ES patients, an Illumina SNP array analysis interrogating mostly coding SNPs was performed as a quality control (QC) measurement and for CNV/ROH detection. Among these patients, clinical chromosomal microarray analysis (CMA) was performed at Baylor Genetics (BG) on 3229 patients, either before, concurrently, or after ES. We retrospectively analyzed the findings from CMA and the QC array. Results The QC array can detect ~ 70% of pathogenic/likely pathogenic CNVs (PCNVs) detectable by CMA. Out of the 11,020 ES cases, the QC array identified PCNVs in 327 patients and uniparental disomy (UPD) disorder-related ROH in 10 patients. The overall PCNV/UPD detection rate was 5.9% in the 3229 ES patients who also had CMA at BG; PCNV/UPD detection rate was higher in concurrent ES and CMA than in ES with prior CMA (7.2% vs 4.6%). The PCNVs/UPD contributed to the molecular diagnoses in 17.4% (189/1089) of molecularly diagnosed ES cases with CMA and were estimated to contribute in 10.6% of all molecularly diagnosed ES cases. Dual diagnoses with both PCNVs and SNVs were detected in 38 patients. PCNVs affecting single recessive disorder genes in a compound heterozygous state with SNVs were detected in 4 patients, and homozygous deletions (mostly exonic deletions) were detected in 17 patients. A higher PCNV detection rate was observed for patients with syndromic phenotypes and/or cardiovascular abnormalities. Conclusions Our clinical genomics study demonstrates that detection of PCNV/UPD through the QC array or CMA increases ES diagnostic rate, provides more precise molecular diagnosis for dominant as well as recessive traits, and enables more complete genetic diagnoses in patients with dual or multiple molecular diagnoses. Concurrent ES and CMA using an array with exonic coverage for disease genes enables most effective detection of both CNVs and SNVs and therefore is recommended especially in time-sensitive clinical situations. Electronic supplementary material The online version of this article (10.1186/s13073-019-0639-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Rajarshi Ghosh
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Bo Yuan
- Baylor Genetics Laboratories, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Pengfei Liu
- Baylor Genetics Laboratories, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Hongzheng Dai
- Baylor Genetics Laboratories, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | | | - Jennifer Scull
- Baylor Genetics Laboratories, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Jennifer E Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | | | - Weimin He
- Baylor Genetics Laboratories, Houston, TX, USA
| | | | - Alicia A Braxton
- Baylor Genetics Laboratories, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Patricia Ward
- Baylor Genetics Laboratories, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Theodore Chiang
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
| | - Chunjing Qu
- Baylor Genetics Laboratories, Houston, TX, USA
| | - Shen Gu
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Chad A Shaw
- Baylor Genetics Laboratories, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Janice L Smith
- Baylor Genetics Laboratories, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Seema Lalani
- Baylor Genetics Laboratories, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Pawel Stankiewicz
- Baylor Genetics Laboratories, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Sau-Wai Cheung
- Baylor Genetics Laboratories, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Carlos A Bacino
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Texas Children's Hospital, Houston, TX, USA
| | - Ankita Patel
- Baylor Genetics Laboratories, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Amy M Breman
- Baylor Genetics Laboratories, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Xia Wang
- Baylor Genetics Laboratories, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Linyan Meng
- Baylor Genetics Laboratories, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Rui Xiao
- Baylor Genetics Laboratories, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Fan Xia
- Baylor Genetics Laboratories, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Donna Muzny
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
| | - Richard A Gibbs
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
| | - Arthur L Beaudet
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Christine M Eng
- Baylor Genetics Laboratories, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA.,Texas Children's Hospital, Houston, TX, USA
| | - Yaping Yang
- Baylor Genetics Laboratories, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Weimin Bi
- Baylor Genetics Laboratories, Houston, TX, USA. .,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.
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