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Qi M, Stenson PD, Ball EV, Tainer JA, Bacolla A, Kehrer-Sawatzki H, Cooper DN, Zhao H. Distinct sequence features underlie microdeletions and gross deletions in the human genome. Hum Mutat 2021; 43:328-346. [PMID: 34918412 PMCID: PMC9069542 DOI: 10.1002/humu.24314] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 11/02/2021] [Accepted: 12/14/2021] [Indexed: 11/18/2022]
Abstract
Microdeletions and gross deletions are important causes (~20%) of human inherited disease and their genomic locations are strongly influenced by the local DNA sequence environment. This notwithstanding, no study has systematically examined their underlying generative mechanisms. Here, we obtained 42,098 pathogenic microdeletions and gross deletions from the Human Gene Mutation Database (HGMD) that together form a continuum of germline deletions ranging in size from 1 to 28,394,429 bp. We analyzed the DNA sequence within 1 kb of the breakpoint junctions and found that the frequencies of non‐B DNA‐forming repeats, GC‐content, and the presence of seven of 78 specific sequence motifs in the vicinity of pathogenic deletions correlated with deletion length for deletions of length ≤30 bp. Further, we found that the presence of DR, GQ, and STR repeats is important for the formation of longer deletions (>30 bp) but not for the formation of shorter deletions (≤30 bp) while significantly (χ2, p < 2E−16) more microhomologies were identified flanking short deletions than long deletions (length >30 bp). We provide evidence to support a functional distinction between microdeletions and gross deletions. Finally, we propose that a deletion length cut‐off of 25–30 bp may serve as an objective means to functionally distinguish microdeletions from gross deletions.
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Affiliation(s)
- Mengling Qi
- Department of Medical Research Center, Sun Yat-sen Memorial Hospital; Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangzhou, China
| | - Peter D Stenson
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - Edward V Ball
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - John A Tainer
- Departments of Cancer Biology and of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Albino Bacolla
- Departments of Cancer Biology and of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | | | - David N Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - Huiying Zhao
- Department of Medical Research Center, Sun Yat-sen Memorial Hospital; Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangzhou, China
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Kelmemi W, Teeuw ME, Bochdanovits Z, Ouburg S, Jonker MA, Alkuraya F, Hashem M, Kayserili H, van Haeringen A, Sheridan E, Masri A, Cobben JM, Rizzu P, Kostense PJ, Dommering CJ, Henneman L, Bouhamed-Chaabouni H, Heutink P, Ten Kate LP, Cornel MC. Determining the genome-wide kinship coefficient seems unhelpful in distinguishing consanguineous couples with a high versus low risk for adverse reproductive outcome. BMC MEDICAL GENETICS 2015; 16:50. [PMID: 26188928 PMCID: PMC4557855 DOI: 10.1186/s12881-015-0191-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 06/17/2015] [Indexed: 11/25/2022]
Abstract
Background Offspring of consanguineous couples are at increased risk of congenital disorders. The risk increases as parents are more closely related. Individuals that have the same degree of relatedness according to their pedigree, show variable genomic kinship coefficients. To investigate whether we can differentiate between couples with high- and low risk for offspring with congenital disorders, we have compared the genomic kinship coefficient of consanguineous parents with a child affected with an autosomal recessive disorder with that of consanguineous parents with only healthy children, corrected for the degree of pedigree relatedness. Methods 151 consanguineous couples (73 cases and 78 controls) from 10 different ethnic backgrounds were genotyped on the Affymetrix platform and passed quality control checks. After pruning SNPs in linkage disequilibrium, 57,358 SNPs remained. Kinship coefficients were calculated using three different toolsets: PLINK, King and IBDelphi, yielding five different estimates (IBDelphi, PLINK (all), PLINK (by population), King robust (all) and King homo (by population)). We performed a one-sided Mann Whitney test to investigate whether the median relative difference regarding observed and expected kinship coefficients is bigger for cases than for controls. Furthermore, we fitted a mixed effects linear model to correct for a possible population effect. Results Although the estimated degrees of genomic relatedness with the different toolsets show substantial variability, correlation measures between the different estimators demonstrated moderate to strong correlations. Controls have higher point estimates for genomic kinship coefficients. The one-sided Mann Whitney test did not show any evidence for a higher median relative difference for cases compared to controls. Neither did the regression analysis exhibit a positive association between case–control status and genomic kinship coefficient. Conclusions In this case–control setting, in which we compared consanguineous couples corrected for degree of pedigree relatedness, a higher degree of genomic relatedness was not significantly associated with a higher likelihood of having an affected child. Further translational research should focus on which parts of the genome and which pathogenic mutations couples are sharing. Looking at relatedness coefficients by determining genome-wide SNPs does not seem to be an effective measure for prospective risk assessment in consanguineous parents. Electronic supplementary material The online version of this article (doi:10.1186/s12881-015-0191-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- W Kelmemi
- Laboratory of Human Genetics, Faculty of Medicine, University of Tunis El Manar, Tunis, Tunisia
| | - M E Teeuw
- Department of Clinical Genetics, VU University Medical Center, Mail BS7, D450, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands.,EMGO Institute for Health and Care Research, VU University Medical Center, Mail BS7, D450, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands
| | - Z Bochdanovits
- Department of Clinical Genetics, VU University Medical Center, Mail BS7, D450, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands
| | - S Ouburg
- Laboratory of Immunogenetics, Medical Microbiology and Infection Control, Research School V-ICI, VU University Medical Center, Amsterdam, The Netherlands
| | - M A Jonker
- Department of Epidemiology and Biostatistics, VU University Medical Center, Amsterdam, The Netherlands
| | - F Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - M Hashem
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - H Kayserili
- Medical Genetics Department, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey
| | - A van Haeringen
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands.,Juliana Children's Hospital, Hague, The Netherlands
| | - E Sheridan
- Bradford Institute for Health Research, Bradford Royal Infirmary, Bradford, UK.,Department of Genetics, Wellcome Trust Brenner Building, St James's University Hospital, Leeds, UK
| | - A Masri
- Division of Child Neurology, Department of Pediatrics, University of Jordan, Amman, Jordan
| | - J M Cobben
- Department of Pediatric Genetics, AMC University Hospital, Amsterdam, The Netherlands
| | - P Rizzu
- Department of Clinical Genetics, VU University Medical Center, Mail BS7, D450, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands.,Genome Biology of Neurodegenerative Diseases, German Center for Neurodegenerative Diseases, Tübingen, Germany
| | - P J Kostense
- Department of Epidemiology and Biostatistics, VU University Medical Center, Amsterdam, The Netherlands
| | - C J Dommering
- Department of Clinical Genetics, VU University Medical Center, Mail BS7, D450, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands
| | - L Henneman
- Department of Clinical Genetics, VU University Medical Center, Mail BS7, D450, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands.,EMGO Institute for Health and Care Research, VU University Medical Center, Mail BS7, D450, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands
| | - H Bouhamed-Chaabouni
- Laboratory of Human Genetics, Faculty of Medicine, University of Tunis El Manar, Tunis, Tunisia
| | - P Heutink
- Department of Clinical Genetics, VU University Medical Center, Mail BS7, D450, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands.,Genome Biology of Neurodegenerative Diseases, German Center for Neurodegenerative Diseases, Tübingen, Germany
| | - L P Ten Kate
- Department of Clinical Genetics, VU University Medical Center, Mail BS7, D450, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands.,EMGO Institute for Health and Care Research, VU University Medical Center, Mail BS7, D450, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands
| | - M C Cornel
- Department of Clinical Genetics, VU University Medical Center, Mail BS7, D450, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands. .,EMGO Institute for Health and Care Research, VU University Medical Center, Mail BS7, D450, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands.
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