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Samudrala SSK, North LM, Stamm KD, Earing MG, Frommelt MA, Willes R, Tripathi S, Dsouza NR, Zimmermann MT, Mahnke DK, Liang HL, Lund M, Lin C, Geddes GC, Mitchell ME, Tomita‐Mitchell A. Novel KLHL26 variant associated with a familial case of Ebstein's anomaly and left ventricular noncompaction. Mol Genet Genomic Med 2020; 8:e1152. [PMID: 31985165 PMCID: PMC7196453 DOI: 10.1002/mgg3.1152] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 01/11/2020] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Ebstein's anomaly (EA) is a rare congenital heart disease of the tricuspid valve and right ventricle. Patients with EA often manifest with left ventricular noncompaction (LVNC), a cardiomyopathy. Despite implication of cardiac sarcomere genes in some cases, very little is understood regarding the genetic etiology of EA/LVNC. Our study describes a multigenerational family with at least 10 of 17 members affected by EA/LVNC. METHODS We performed echocardiography on all family members and conducted exome sequencing of six individuals. After identifying candidate variants using two different bioinformatic strategies, we confirmed segregation with phenotype using Sanger sequencing. We investigated structural implications of candidate variants using protein prediction models. RESULTS Exome sequencing analysis of four affected and two unaffected members identified a novel, rare, and damaging coding variant in the Kelch-like family member 26 (KLHL26) gene located on chromosome 19 at position 237 of the protein (GRCh37). This variant region was confirmed by Sanger sequencing in the remaining family members. KLHL26 (c.709C > T p.R237C) segregates only with EA/LVNC-affected individuals (FBAT p < .05). Investigating structural implications of the candidate variant using protein prediction models suggested that the KLHL26 variant disrupts electrostatic interactions when binding to part of the ubiquitin proteasome, specifically Cullin3 (CUL3), a component of E3 ubiquitin ligase. CONCLUSION In this familial case of EA/LVNC, we have identified a candidate gene variant, KLHL26 (p.R237C), which may have an important role in ubiquitin-mediated protein degradation during cardiac development.
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Affiliation(s)
- Sai Suma K. Samudrala
- Department of Cell Biology, Neurobiology and AnatomyMedical College of WisconsinMilwaukeeWIUSA
| | - Lauren M. North
- Department of Otolaryngology and Communication SciencesMedical College of WisconsinMilwaukeeWIUSA
| | - Karl D. Stamm
- Department of SurgeryDivision of Cardiothoracic SurgeryMedical College of WisconsinMilwaukeeWIUSA
| | - Michael G. Earing
- Department of PediatricsChildren’s Hospital of WisconsinMilwaukeeWIUSA
- Herma Heart InstituteChildren’s Hospital of WisconsinMilwaukeeWIUSA
| | - Michele A. Frommelt
- Department of PediatricsChildren’s Hospital of WisconsinMilwaukeeWIUSA
- Herma Heart InstituteChildren’s Hospital of WisconsinMilwaukeeWIUSA
| | - Richard Willes
- Department of PediatricsChildren’s Hospital of WisconsinMilwaukeeWIUSA
| | - Swarnendu Tripathi
- Bioinformatics Research and Developmental LabGenomic Sciences and Precision Medicine CenterMedical College of WisconsinMilwaukeeWIUSA
| | - Nikita R. Dsouza
- Bioinformatics Research and Developmental LabGenomic Sciences and Precision Medicine CenterMedical College of WisconsinMilwaukeeWIUSA
| | - Michael T. Zimmermann
- Bioinformatics Research and Developmental LabGenomic Sciences and Precision Medicine CenterMedical College of WisconsinMilwaukeeWIUSA
- Clinical and Translational Science InstituteMedical College of WisconsinMilwaukeeWIUSA
| | - Donna K. Mahnke
- Department of SurgeryDivision of Cardiothoracic SurgeryMedical College of WisconsinMilwaukeeWIUSA
| | - Huan Ling Liang
- Department of SurgeryDivision of Cardiothoracic SurgeryMedical College of WisconsinMilwaukeeWIUSA
| | - Michael Lund
- Department of Obstetrics and GynecologyMedical College of WisconsinMilwaukeeWIUSA
| | - Chien‐Wei Lin
- Division of BiostatisticsMedical College of WisconsinMilwaukeeWIUSA
| | | | - Michael E. Mitchell
- Department of SurgeryDivision of Cardiothoracic SurgeryMedical College of WisconsinMilwaukeeWIUSA
- Herma Heart InstituteChildren’s Hospital of WisconsinMilwaukeeWIUSA
| | - Aoy Tomita‐Mitchell
- Department of SurgeryDivision of Cardiothoracic SurgeryMedical College of WisconsinMilwaukeeWIUSA
- Herma Heart InstituteChildren’s Hospital of WisconsinMilwaukeeWIUSA
- Department of Biomedical EngineeringMedical College of WisconsinMilwaukeeWIUSA
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Sicko RJ, Browne ML, Rigler SL, Druschel CM, Liu G, Fan R, Romitti PA, Caggana M, Kay DM, Brody LC, Mills JL. Genetic Variants in Isolated Ebstein Anomaly Implicated in Myocardial Development Pathways. PLoS One 2016; 11:e0165174. [PMID: 27788187 PMCID: PMC5082909 DOI: 10.1371/journal.pone.0165174] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 10/08/2016] [Indexed: 01/21/2023] Open
Abstract
Ebstein anomaly (EA) is a rare heart defect in which the tricuspid valve is malformed and displaced. The tricuspid valve abnormalities can lead to backflow of blood from the right ventricle to the right atrium, preventing proper circulation of blood to the lungs. Although the etiology of EA is largely unresolved, increased prevalence of EA in those with a family history of congenital heart disease suggests EA has a genetic component. Copy number variants (CNVs) are a major source of genetic variation and have been implicated in a range of congenital heart defect phenotypes. We performed a systematic, genome-wide search for CNVs in 47 isolated EA cases using genotyping microarrays. In addition, we used a custom HaloPlex panel to sequence three known EA genes and 47 candidate EA genes. We identified 35 candidate CNVs in 24 (51%) EA cases. Rare sequence variants in genes associated with cardiomyopathy were identified in 11 (23%) EA cases. Two CNVs near the transcriptional repressor HEY1, a member of the NOTCH signaling pathway, were identified in three unrelated cases. All other candidate CNVs were each identified in a single case. At least 11 of 35 candidate CNVs include genes involved in myocardial development or function, including multiple genes in the BMP signaling pathway. We identified enrichment of gene sets involved in histone modification and cardiomyocyte differentiation, supporting the involvement of the developing myocardium in the etiology of EA. Gene set enrichment analysis also identified ribosomal RNA processing, a potentially novel pathway of altered cardiac development in EA. Our results suggest an altered myocardial program may contribute to abnormal tricuspid valve development in EA. Future studies should investigate abnormal differentiation of cardiomyocytes as a potential etiological factor in EA.
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Affiliation(s)
- Robert J. Sicko
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, New York, United States of America
| | - Marilyn L. Browne
- Congenital Malformations Registry, New York State Department of Health, Albany, New York, United States of America
- Department of Epidemiology and Biostatistics, University at Albany School of Public Health, Rensselaer, New York, United States of America
| | - Shannon L. Rigler
- Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, United States of America
- Department of Neonatology, Walter Reed National Military Medical Center, Bethesda, Maryland, United States of America
| | - Charlotte M. Druschel
- Congenital Malformations Registry, New York State Department of Health, Albany, New York, United States of America
- Department of Epidemiology and Biostatistics, University at Albany School of Public Health, Rensselaer, New York, United States of America
| | - Gang Liu
- Congenital Malformations Registry, New York State Department of Health, Albany, New York, United States of America
| | - Ruzong Fan
- Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, United States of America
| | - Paul A. Romitti
- Department of Epidemiology, College of Public Health, The University of Iowa, Iowa City, Iowa, United States of America
| | - Michele Caggana
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, New York, United States of America
| | - Denise M. Kay
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, New York, United States of America
| | - Lawrence C. Brody
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, United States of America
| | - James L. Mills
- Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, United States of America
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