Whole Genome Sequencing Expands Diagnostic Utility and Improves Clinical Management in Pediatric Medicine

Dimitri J Stavropoulos, Daniele Merico, Rebekah Jobling, Sarah Bowdin, Nasim Monfared, Bhooma Thiruvahindrapuram, Thomas Nalpathamkalam, Giovanna Pellecchia, Ryan K C Yuen, Michael J Szego, Robin Z Hayeems, Randi Zlotnik Shaul, Michael Brudno, Marta Girdea, Brendan Frey, Babak Alipanahi, Sohnee Ahmed, Riyana Babul-Hirji, Ramses Badilla Porras, Melissa T Carter, Lauren Chad, Ayeshah Chaudhry, David Chitayat, Soghra Jougheh Doust, Cheryl Cytrynbaum, Lucie Dupuis, Resham Ejaz, Leona Fishman, Andrea Guerin, Bita Hashemi, Mayada Helal, Stacy Hewson, Michal Inbar-Feigenberg, Peter Kannu, Natalya Karp, Raymond Kim, Jonathan Kronick, Eriskay Liston, Heather MacDonald, Saadet Mercimek-Mahmutoglu, Roberto Mendoza-Londono, Enas Nasr, Graeme Nimmo, Nicole Parkinson, Nada Quercia, Julian Raiman, Maian Roifman, Andreas Schulze, Andrea Shugar, Cheryl Shuman, Pierre Sinajon, Komudi Siriwardena, Rosanna Weksberg, Grace Yoon, Chris Carew, Raith Erickson, Richard A Leach, Robert Klein, Peter N Ray, M Stephen Meyn, Stephen W Scherer, Ronald D Cohn, Christian R Marshall, Dimitri J Stavropoulos, Daniele Merico, Rebekah Jobling, Sarah Bowdin, Nasim Monfared, Bhooma Thiruvahindrapuram, Thomas Nalpathamkalam, Giovanna Pellecchia, Ryan K C Yuen, Michael J Szego, Robin Z Hayeems, Randi Zlotnik Shaul, Michael Brudno, Marta Girdea, Brendan Frey, Babak Alipanahi, Sohnee Ahmed, Riyana Babul-Hirji, Ramses Badilla Porras, Melissa T Carter, Lauren Chad, Ayeshah Chaudhry, David Chitayat, Soghra Jougheh Doust, Cheryl Cytrynbaum, Lucie Dupuis, Resham Ejaz, Leona Fishman, Andrea Guerin, Bita Hashemi, Mayada Helal, Stacy Hewson, Michal Inbar-Feigenberg, Peter Kannu, Natalya Karp, Raymond Kim, Jonathan Kronick, Eriskay Liston, Heather MacDonald, Saadet Mercimek-Mahmutoglu, Roberto Mendoza-Londono, Enas Nasr, Graeme Nimmo, Nicole Parkinson, Nada Quercia, Julian Raiman, Maian Roifman, Andreas Schulze, Andrea Shugar, Cheryl Shuman, Pierre Sinajon, Komudi Siriwardena, Rosanna Weksberg, Grace Yoon, Chris Carew, Raith Erickson, Richard A Leach, Robert Klein, Peter N Ray, M Stephen Meyn, Stephen W Scherer, Ronald D Cohn, Christian R Marshall

Abstract

The standard of care for first-tier clinical investigation of the etiology of congenital malformations and neurodevelopmental disorders is chromosome microarray analysis (CMA) for copy number variations (CNVs), often followed by gene(s)-specific sequencing searching for smaller insertion-deletions (indels) and single nucleotide variant (SNV) mutations. Whole genome sequencing (WGS) has the potential to capture all classes of genetic variation in one experiment; however, the diagnostic yield for mutation detection of WGS compared to CMA, and other tests, needs to be established. In a prospective study we utilized WGS and comprehensive medical annotation to assess 100 patients referred to a paediatric genetics service and compared the diagnostic yield versus standard genetic testing. WGS identified genetic variants meeting clinical diagnostic criteria in 34% of cases, representing a 4-fold increase in diagnostic rate over CMA (8%) (p-value = 1.42e-05) alone and >2-fold increase in CMA plus targeted gene sequencing (13%) (p-value = 0.0009). WGS identified all rare clinically significant CNVs that were detected by CMA. In 26 patients, WGS revealed indel and missense mutations presenting in a dominant (63%) or a recessive (37%) manner. We found four subjects with mutations in at least two genes associated with distinct genetic disorders, including two cases harboring a pathogenic CNV and SNV. When considering medically actionable secondary findings in addition to primary WGS findings, 38% of patients would benefit from genetic counseling. Clinical implementation of WGS as a primary test will provide a higher diagnostic yield than conventional genetic testing and potentially reduce the time required to reach a genetic diagnosis.

Keywords: Chromosomal Microarray Analysis; Diagnostic Yield; Whole Genome Sequencing.

Conflict of interest statement

Competing Interests: DM RJ, NM, BT, TN, GP, RKCY, MS, RH, RZS, MB, MG, BF, BA, SA, MTC, LC, AC, CC, LD, RE, LF, AG, BH, MH, SH, MIF, PK, NK, RK, JK, EL, HM, SMM, RML, EN, GN, NP, NQ, JR, MR, AS, AS, CS, PS, KS, RW, GY, CC, SWS, RDC, and CRM declare no conflicts of interest. SB, DJS, PNR and MSM are scientific advisors for Gene42 Inc., which provides support services for the free (open source) PhenoTips software. RE and RK are employees of Complete Genomics. RAL was an employee of Complete Genomics at the time of the study and is currently employed by WuXi NextCODE Genomics.

Figures

Figure 1
Figure 1
Overview of study design comparing the diagnostic yield of whole-genome sequencing compared with standard of care genetic testing. CMA, chromosomal microarray analysis; SNV, single-nucleotide variant; CNV, copy-number variant; HPO, Human Phenotype Ontology; Dx, diagnostic.

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Source: PubMed

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