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Evans DR, Qiao Y, Trost B, Calli K, Martell S, Jones SJM, Scherer SW, Lewis MES. Complex Autism Spectrum Disorder with Epilepsy, Strabismus and Self-Injurious Behaviors in a Patient with a De Novo Heterozygous POLR2A Variant. Genes (Basel) 2022; 13:genes13030470. [PMID: 35328024 PMCID: PMC8955435 DOI: 10.3390/genes13030470] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/28/2022] [Accepted: 03/03/2022] [Indexed: 02/01/2023] Open
Abstract
Autism spectrum disorder (ASD) describes a complex and heterogenous group of neurodevelopmental disorders. Whole genome sequencing continues to shed light on the multifactorial etiology of ASD. Dysregulated transcriptional pathways have been implicated in neurodevelopmental disorders. Emerging evidence suggests that de novo POLR2A variants cause a newly described phenotype called ‘Neurodevelopmental Disorder with Hypotonia and Variable Intellectual and Behavioral Abnormalities’ (NEDHIB). The variable phenotype manifests with a spectrum of features; primarily early onset hypotonia and delay in developmental milestones. In this study, we investigate a patient with complex ASD involving epilepsy and strabismus. Whole genome sequencing of the proband−parent trio uncovered a novel de novo POLR2A variant (c.1367T>C, p. Val456Ala) in the proband. The variant appears deleterious according to in silico tools. We describe the phenotype in our patient, who is now 31 years old, draw connections between the previously reported phenotypes and further delineate this emerging neurodevelopmental phenotype. This study sheds new insights into this neurodevelopmental disorder, and more broadly, the genetic etiology of ASD.
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Affiliation(s)
- Daniel R. Evans
- Department of Family Practice, University of British Columbia (UBC), Victoria, BC V8R 1J8, Canada;
| | - Ying Qiao
- Medical Genetics, University of British Columbia (UBC), Vancouver, BC V6H 3N1, Canada; (Y.Q.); (K.C.); (S.M.); (S.J.M.J.)
- BC Children’s Hospital Research Institute, Vancouver, BC V6H 3N1, Canada
- iTARGET Autism, Vancouver, BC V6H 3N1, Canada
| | - Brett Trost
- The Centre for Applied Genomics and McLaughlin Centre, Hospital for Sick Children, University of Toronto, Toronto, ON M5G 0A4, Canada; (B.T.); (S.W.S.)
| | - Kristina Calli
- Medical Genetics, University of British Columbia (UBC), Vancouver, BC V6H 3N1, Canada; (Y.Q.); (K.C.); (S.M.); (S.J.M.J.)
- BC Children’s Hospital Research Institute, Vancouver, BC V6H 3N1, Canada
- iTARGET Autism, Vancouver, BC V6H 3N1, Canada
| | - Sally Martell
- Medical Genetics, University of British Columbia (UBC), Vancouver, BC V6H 3N1, Canada; (Y.Q.); (K.C.); (S.M.); (S.J.M.J.)
- BC Children’s Hospital Research Institute, Vancouver, BC V6H 3N1, Canada
- iTARGET Autism, Vancouver, BC V6H 3N1, Canada
| | - Steven J. M. Jones
- Medical Genetics, University of British Columbia (UBC), Vancouver, BC V6H 3N1, Canada; (Y.Q.); (K.C.); (S.M.); (S.J.M.J.)
- iTARGET Autism, Vancouver, BC V6H 3N1, Canada
- Michael Smith Genome Sciences Centre, Vancouver, BC V6H 3N1, Canada
| | - Stephen W. Scherer
- The Centre for Applied Genomics and McLaughlin Centre, Hospital for Sick Children, University of Toronto, Toronto, ON M5G 0A4, Canada; (B.T.); (S.W.S.)
| | - M. E. Suzanne Lewis
- Medical Genetics, University of British Columbia (UBC), Vancouver, BC V6H 3N1, Canada; (Y.Q.); (K.C.); (S.M.); (S.J.M.J.)
- BC Children’s Hospital Research Institute, Vancouver, BC V6H 3N1, Canada
- iTARGET Autism, Vancouver, BC V6H 3N1, Canada
- Correspondence:
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Deb S, Kuckovic A, Anderson A, Berei J, Sreenivasappa S, Ross J, Martell S, Vitali C, Schulz W, Racherla K, Puri N. P1.19 Lung Cancer Screening Initiative and Identification of Novel Blood Biomarkers for Early Detection of Lung Cancer. J Thorac Oncol 2019. [DOI: 10.1016/j.jtho.2019.09.076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Qiao Y, Bagheri H, Tang F, Badduke C, Martell S, Lewis SME, Robinson W, Connolly MB, Arbour L, Rajcan-Separovic E. Exome sequencing identified a de novo mutation of PURA gene in a patient with familial Xp22.31 microduplication. Eur J Med Genet 2018; 62:103-108. [PMID: 29908350 DOI: 10.1016/j.ejmg.2018.06.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 06/08/2018] [Accepted: 06/10/2018] [Indexed: 11/28/2022]
Abstract
The clinical significance of Xp22.31 microduplication is controversial as it is reported in subjects with developmental delay (DD), their unaffected relatives and unrelated controls. We performed multifaceted studies in a family of a boy with hypotonia, dysmorphic features and DD who carried a 600 Kb Xp22.31 microduplication (7515787-8123310bp, hg19) containing two genes, VCX and PNPLA4. The duplication was transmitted from his cognitively normal maternal grandfather. We found no evidence of the duplication causing the proband's DD and congenital anomalies based on unaltered expression of PNPLA4 in the proband and his mother in comparison to controls and preferential activation of the paternal chromosome X with Xp22.31 duplication in proband's mother. However, a de novo, previously reported deleterious, missense mutation in Pur-alpha gene (PURA) (5q31.2), with a role in neuronal differentiation was detected in the proband by exome sequencing. We propose that the variability in the phenotype in carriers of Xp22.31 microduplication can be due to a second and more deleterious genetic mutation in more severely affected carriers. Widespread use of whole genome next generation sequencing in families with Xp22.31 CNV could help identify such cases.
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Affiliation(s)
- Ying Qiao
- Department of Pathology and Laboratory Medicine, UBC, Vancouver, BC, Canada; BC Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Hani Bagheri
- Department of Pathology and Laboratory Medicine, UBC, Vancouver, BC, Canada
| | - Flamingo Tang
- Department of Pathology and Laboratory Medicine, UBC, Vancouver, BC, Canada
| | | | - Sally Martell
- Department of Pathology and Laboratory Medicine, UBC, Vancouver, BC, Canada
| | - Suzanne M E Lewis
- BC Children's Hospital Research Institute, Vancouver, BC, Canada; Department of Medical Genetics, UBC, Vancouver, BC, Canada
| | - Wendy Robinson
- Department of Medical Genetics, UBC, Vancouver, BC, Canada
| | - Mary B Connolly
- Division of Pediatric Neurology, Department of Pediatrics, UBC and BC Children's Hospital, Vancouver, BC, Canada
| | - Laura Arbour
- Department of Medical Genetics, University of Victoria, Victoria, BC, Canada.
| | - Evica Rajcan-Separovic
- Department of Pathology and Laboratory Medicine, UBC, Vancouver, BC, Canada; BC Children's Hospital Research Institute, Vancouver, BC, Canada.
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Qiao Y, Badduke C, Tang F, Cowieson D, Martell S, Lewis SME, Peñaherrera MS, Robinson WP, Volchuk A, Rajcan-Separovic E. Whole exome sequencing of families with 1q21.1 microdeletion or microduplication. Am J Med Genet A 2017; 173:1782-1791. [DOI: 10.1002/ajmg.a.38247] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 03/16/2017] [Indexed: 01/24/2023]
Affiliation(s)
- Ying Qiao
- Department of Pathology; University of British Columbia (UBC); Vancouver British Columbia Canada
- BC Children's Hospital Research Institute; Vancouver British Columbia Canada
| | - Chansonette Badduke
- Department of Pathology; University of British Columbia (UBC); Vancouver British Columbia Canada
| | - Flamingo Tang
- Department of Pathology; University of British Columbia (UBC); Vancouver British Columbia Canada
| | - David Cowieson
- Division of Advanced Diagnostics-Metabolism Toronto General Research Institute; University Health Network; Toronto Ontario Canada
| | - Sally Martell
- Department of Pathology; University of British Columbia (UBC); Vancouver British Columbia Canada
- BC Children's Hospital Research Institute; Vancouver British Columbia Canada
| | | | - Maria S. Peñaherrera
- BC Children's Hospital Research Institute; Vancouver British Columbia Canada
- Department of Medical Genetics; UBC; Vancouver British Columbia Canada
| | - Wendy P. Robinson
- BC Children's Hospital Research Institute; Vancouver British Columbia Canada
- Department of Medical Genetics; UBC; Vancouver British Columbia Canada
| | - Allen Volchuk
- Keenan Research Centre for Biomedical Science; St. Michael's Hospital; Toronto Ontario Canada
| | - Evica Rajcan-Separovic
- Department of Pathology; University of British Columbia (UBC); Vancouver British Columbia Canada
- BC Children's Hospital Research Institute; Vancouver British Columbia Canada
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Bagheri H, Badduke C, Qiao Y, Colnaghi R, Abramowicz I, Alcantara D, Dunham C, Wen J, Wildin RS, Nowaczyk MJ, Eichmeyer J, Lehman A, Maranda B, Martell S, Shan X, Lewis SM, O’Driscoll M, Gregory-Evans CY, Rajcan-Separovic E. Identifying candidate genes for 2p15p16.1 microdeletion syndrome using clinical, genomic, and functional analysis. JCI Insight 2016; 1:e85461. [PMID: 27699255 PMCID: PMC5033885 DOI: 10.1172/jci.insight.85461] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 02/09/2016] [Indexed: 01/14/2023] Open
Abstract
The 2p15p16.1 microdeletion syndrome has a core phenotype consisting of intellectual disability, microcephaly, hypotonia, delayed growth, common craniofacial features, and digital anomalies. So far, more than 20 cases of 2p15p16.1 microdeletion syndrome have been reported in the literature; however, the size of the deletions and their breakpoints vary, making it difficult to identify the candidate genes. Recent reports pointed to 4 genes (XPO1, USP34, BCL11A, and REL) that were included, alone or in combination, in the smallest deletions causing the syndrome. Here, we describe 8 new patients with the 2p15p16.1 deletion and review all published cases to date. We demonstrate functional deficits for the above 4 candidate genes using patients' lymphoblast cell lines (LCLs) and knockdown of their orthologs in zebrafish. All genes were dosage sensitive on the basis of reduced protein expression in LCLs. In addition, deletion of XPO1, a nuclear exporter, cosegregated with nuclear accumulation of one of its cargo molecules (rpS5) in patients' LCLs. Other pathways associated with these genes (e.g., NF-κB and Wnt signaling as well as the DNA damage response) were not impaired in patients' LCLs. Knockdown of xpo1a, rel, bcl11aa, and bcl11ab resulted in abnormal zebrafish embryonic development including microcephaly, dysmorphic body, hindered growth, and small fins as well as structural brain abnormalities. Our multifaceted analysis strongly implicates XPO1, REL, and BCL11A as candidate genes for 2p15p16.1 microdeletion syndrome.
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Affiliation(s)
- Hani Bagheri
- Department of Pathology and Laboratory Medicine, University of British Columbia (UBC), Vancouver, British Columbia, Canada
- Child and Family Research Institute, Vancouver, British Columbia, Canada
| | - Chansonette Badduke
- Department of Pathology and Laboratory Medicine, University of British Columbia (UBC), Vancouver, British Columbia, Canada
- Child and Family Research Institute, Vancouver, British Columbia, Canada
| | - Ying Qiao
- Department of Pathology and Laboratory Medicine, University of British Columbia (UBC), Vancouver, British Columbia, Canada
- Child and Family Research Institute, Vancouver, British Columbia, Canada
| | - Rita Colnaghi
- Human DNA Damage Response Disorders Group, Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
| | - Iga Abramowicz
- Human DNA Damage Response Disorders Group, Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
| | - Diana Alcantara
- Human DNA Damage Response Disorders Group, Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
| | - Christopher Dunham
- Department of Pathology and Laboratory Medicine, University of British Columbia (UBC), Vancouver, British Columbia, Canada
| | - Jiadi Wen
- University of Texas at Dallas, Dallas, Texas, USA
| | | | - Malgorzata J.M. Nowaczyk
- Department of Pathology and Molecular Medicine, McMaster University Medical Centre, Hamilton, Ontario, Canada
| | | | - Anna Lehman
- Department of Medical Genetics, UBC, Vancouver, British Columbia, Canada
| | - Bruno Maranda
- Medical Genetics, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Sally Martell
- Department of Pathology and Laboratory Medicine, University of British Columbia (UBC), Vancouver, British Columbia, Canada
- Child and Family Research Institute, Vancouver, British Columbia, Canada
| | - Xianghong Shan
- Department of Ophthalmology, UBC, Vancouver, British Columbia, Canada
| | - Suzanne M.E. Lewis
- Department of Medical Genetics, UBC, Vancouver, British Columbia, Canada
| | - Mark O’Driscoll
- Human DNA Damage Response Disorders Group, Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
| | | | - Evica Rajcan-Separovic
- Department of Pathology and Laboratory Medicine, University of British Columbia (UBC), Vancouver, British Columbia, Canada
- Child and Family Research Institute, Vancouver, British Columbia, Canada
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Qiao Y, Wen J, Tang F, Martell S, Shomer N, Leung PCK, Stephenson MD, Rajcan-Separovic E. Whole exome sequencing in recurrent early pregnancy loss. Mol Hum Reprod 2016; 22:364-72. [PMID: 26826164 DOI: 10.1093/molehr/gaw008] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 01/25/2016] [Indexed: 12/20/2022] Open
Abstract
STUDY HYPOTHESIS Exome sequencing can identify genetic causes of idiopathic recurrent pregnancy loss (RPL). STUDY FINDING We identified compound heterozygous deleterious mutations affecting DYNC2H1 and ALOX15 in two out of four families with RPL. Both genes have a role in early development. Bioinformatics analysis of all genes with rare and putatively pathogenic mutations in miscarriages and couples showed enrichment in pathways relevant to pregnancy loss, including the complement and coagulation cascades pathways. WHAT IS KNOWN ALREADY Next generation sequencing (NGS) is increasingly being used to identify known and novel gene mutations in children with developmental delay and in fetuses with ultrasound-detected anomalies. In contrast, NGS is rarely used to study pregnancy loss. Chromosome microarray analysis detects putatively causative DNA copy number variants (CNVs) in ∼2% of miscarriages and CNVs of unknown significance (predominantly parental in origin) in up to 40% of miscarriages. Therefore, a large number of miscarriages still have an unknown cause. STUDY DESIGN, SAMPLES/MATERIALS, METHODS Whole exome sequencing (WES) was performed using Illumina HiSeq 2000 platform on seven euploid miscarriages from four families with RPL. Golden Helix SVS v8.1.5 was used for data assessment and inheritance analysis for deleterious DNA variants predicted to severely disrupt protein-coding genes by introducing a frameshift, loss of the stop codon, gain of the stop codon, changes in splicing or the initial codon. Webgestalt (http://bioinfo.vanderbilt.edu/webgestalt/) was used for pathway and disease association enrichment analysis of a gene pool containing putatively pathogenic variants in miscarriages and couples in comparison to control gene pools. MAIN RESULTS AND THE ROLE OF CHANCE Compound heterozygous mutations in DYNC2H1 and ALOX15 were identified in miscarriages from two families with RPL. DYNC2H1 is involved in cilia biogenesis and has been associated with fetal lethality in humans. ALOX15 is expressed in placenta and its dysregulation has been associated with inflammation, placental, dysfunction, abnormal oxidative stress response and angiogenesis. The pool of putatively pathogenic single nucleotide variants (SNVs) and small insertions and deletions (indels) detected in the miscarriages showed enrichment in 'complement and coagulation cascades pathway', and 'ciliary motility disorders'. We conclude that CNVs, individual SNVs and pool of deleterious gene mutations identified by exome sequencing could contribute to RPL. LIMITATIONS, REASONS FOR CAUTION The size of our sample cohort is small. The functional effect of candidate mutations should be evaluated to determine whether the mutations are causative. WIDER IMPLICATIONS OF THE FINDINGS This is the first study to assess whether SNVs may contribute to the pathogenesis of miscarriage. Furthermore, our findings suggest that collective effect of mutations in relevant biological pathways could be implicated in RPL. STUDY FUNDING AND COMPETING INTERESTS The study was funded by Canadian Institutes of Health Research (grant MOP 106467) and Michael Smith Foundation of Health Research Career Scholar salary award to ERS.
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Affiliation(s)
- Ying Qiao
- Department of Pathology, BC Child and Family Research Institute (CFRI), University of British Columbia (UBC), Vancouver, BC, Canada
| | - Jiadi Wen
- University of Texas, Dallas, TX, USA
| | - Flamingo Tang
- Department of Pathology, BC Child and Family Research Institute (CFRI), University of British Columbia (UBC), Vancouver, BC, Canada
| | - Sally Martell
- Department of Pathology, BC Child and Family Research Institute (CFRI), University of British Columbia (UBC), Vancouver, BC, Canada
| | - Naomi Shomer
- Department of Pathology, BC Child and Family Research Institute (CFRI), University of British Columbia (UBC), Vancouver, BC, Canada
| | - Peter C K Leung
- Department of Obstetrics and Gynaecology, University of British Columbia, Vancouver, BC, Canada V6Z 2 K5
| | - Mary D Stephenson
- University of Chicago and University of Illinois at Chicago, Chicago, IL, USA
| | - Evica Rajcan-Separovic
- Department of Pathology, BC Child and Family Research Institute (CFRI), University of British Columbia (UBC), Vancouver, BC, Canada
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Bagheri H, Wen J, Hanna CW, Tang F, Martell S, Qiao Y, Leung P, Robinson W, Stephenson M, Rajcan-Separovic E. MG-123 Genomics of early pregnancy loss. J Med Genet 2015. [DOI: 10.1136/jmedgenet-2015-103577.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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8
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Qiao Y, Tang F, Martell S, Badduke C, Cowieson D, Chow E, Marles S, Lewis SME, Volchuk A, Rajcan-Separovic E. MG-118 Towards understanding phenotypic variability using exome sequencing. J Med Genet 2015. [DOI: 10.1136/jmedgenet-2015-103577.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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9
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Wen J, Hanna CW, Martell S, Leung PC, Lewis SM, Robinson WP, Stephenson MD, Rajcan-Separovic E. Functional consequences of copy number variants in miscarriage. Mol Cytogenet 2015; 8:6. [PMID: 25674159 PMCID: PMC4324423 DOI: 10.1186/s13039-015-0109-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [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: 12/13/2014] [Accepted: 01/09/2015] [Indexed: 02/01/2023] Open
Abstract
Background The presence of unique copy number variations (CNVs) in miscarriages suggests that their integral genes have a role in maintaining early pregnancy. In our previous work, we identified 19 unique CNVs in ~40% of studied euploid miscarriages, which were predominantly familial in origin. In our current work, we assessed their relevance to miscarriage by expression analysis of 14 genes integral to CNVs in available miscarriage chorionic villi. As familial CNVs could cause miscarriage due to imprinting effect, we investigated the allelic expression of one of the genes (TIMP2) previously suggested to be maternally expressed in placenta and involved in placental remodelling and embryo development. Results Six out of fourteen genes had detectable expression in villi and for three genes the RNA and protein expression was altered due to maternal CNVs. These genes were integral to duplication on Xp22.2 (TRAPPC2 and OFD1) or disrupted by a duplication mapping to 17q25.3 (TIMP2). RNA and protein expression was increased for TRAPPC2 and OFD1 and reduced for TIMP2 in carrier miscarriages. The three genes have roles in processes important for pregnancy development such as extracellular matrix homeostasis (TIMP2 and TRAPPC2) and cilia function (OFD1). TIMP2 allelic expression was not affected by the CNV in miscarriages in comparison to control elective terminations. Conclusion We propose that functional studies of CNVs could help determine if and how the miscarriage CNVs affect the expression of integral genes. In case of parental CNVs, assessment of the function of their integral genes in parental reproductive tissues should be also considered in the future, especially if they affect processes relevant for pregnancy development and support. Electronic supplementary material The online version of this article (doi:10.1186/s13039-015-0109-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jiadi Wen
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, V6T 2B5 Canada.,Child & Family Research Institute, Vancouver, V5Z 4H4 Canada
| | - Courtney W Hanna
- Child & Family Research Institute, Vancouver, V5Z 4H4 Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, V6T 1Z3 Canada
| | - Sally Martell
- Child & Family Research Institute, Vancouver, V5Z 4H4 Canada
| | - Peter Ck Leung
- Child & Family Research Institute, Vancouver, V5Z 4H4 Canada.,Department of Obstetrics and Gynaecology, University of British Columbia, Vancouver, V6Z 2 K5 Canada
| | - Suzanne Me Lewis
- Department of Medical Genetics, University of British Columbia, Vancouver, V6T 1Z3 Canada
| | - Wendy P Robinson
- Child & Family Research Institute, Vancouver, V5Z 4H4 Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, V6T 1Z3 Canada
| | - Mary D Stephenson
- Department of Obstetrics and Gynecology, University of Illinois at Chicago, Chicago, 60612 USA
| | - Evica Rajcan-Separovic
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, V6T 2B5 Canada.,Child & Family Research Institute, Vancouver, V5Z 4H4 Canada
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Qiao Y, Mondal K, Trapani V, Wen J, Carpenter G, Wildin R, Price EM, Gibbons RJ, Eichmeyer J, Jiang R, DuPont B, Martell S, Lewis SME, Robinson WP, O'Driscoll M, Wolf FI, Zwick ME, Rajcan-Separovic E. Variant ATRX syndrome with dysfunction of ATRX and MAGT1 genes. Hum Mutat 2014; 35:58-62. [PMID: 24130152 DOI: 10.1002/humu.22465] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 09/24/2013] [Accepted: 10/02/2013] [Indexed: 01/10/2023]
Abstract
A 0.8 kb intronic duplication in MAGT1 and a single base pair deletion in the last exon of ATRX were identified using a chromosome X-specific microarray and exome sequencing in a family with five males demonstrating intellectual disability (ID) and unusual skin findings (e.g., generalized pruritus). MAGT1 is an Mg²⁺ transporter previously associated with primary immunodeficiency and ID, whereas mutations in ATRX cause ATRX-ID syndrome. In patient cells, the function of ATRX was demonstrated to be abnormal based on altered RNA/protein expression, hypomethylation of rDNA, and abnormal cytokinesis. Dysfunction of MAGT1 was reflected in reduced RNA/protein expression and Mg²⁺ influx. The mutation in ATRX most likely explains the ID, whereas MAGT1 disruption could be linked to abnormal skin findings, as normal magnesium homeostasis is necessary for skin health. This work supports observations that multiple mutations collectively contribute to the phenotypic variability of syndromic ID, and emphasizes the importance of correlating clinical phenotype with genomic and cell function analyses.
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Wen J, Lopes F, Soares G, Farrell SA, Nelson C, Qiao Y, Martell S, Badukke C, Bessa C, Ylstra B, Lewis S, Isoherranen N, Maciel P, Rajcan-Separovic E. Phenotypic and functional consequences of haploinsufficiency of genes from exocyst and retinoic acid pathway due to a recurrent microdeletion of 2p13.2. Orphanet J Rare Dis 2013; 8:100. [PMID: 23837398 PMCID: PMC3710273 DOI: 10.1186/1750-1172-8-100] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 07/03/2013] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Rare, recurrent genomic imbalances facilitate the association of genotype with abnormalities at the "whole body" level. However, at the cellular level, the functional consequences of recurrent genomic abnormalities and how they can be linked to the phenotype are much less investigated. METHOD AND RESULTS We report an example of a functional analysis of two genes from a new, overlapping microdeletion of 2p13.2 region (from 72,140,702-72,924,626). The subjects shared intellectual disability (ID), language delay, hyperactivity, facial asymmetry, ear malformations, and vertebral and/or craniofacial abnormalities. The overlapping region included two genes, EXOC6B and CYP26B1, which are involved in exocytosis/Notch signaling and retinoic acid (RA) metabolism, respectively, and are of critical importance for early morphogenesis, symmetry as well as craniofacial, skeleton and brain development. The abnormal function of EXOC6B was documented in patient lymphoblasts by its reduced expression and with perturbed expression of Notch signaling pathway genes HES1 and RBPJ, previously noted to be the consequence of EXOC6B dysfunction in animal and cell line models. Similarly, the function of CYP26B1 was affected by the deletion since the retinoic acid induced expression of this gene in patient lymphoblasts was significantly lower compared to controls (8% of controls). CONCLUSION Haploinsufficiency of CYP26B1 and EXOC6B genes involved in retinoic acid and exocyst/Notch signaling pathways, respectively, has not been reported previously in humans. The developmental anomalies and phenotypic features of our subjects are in keeping with the dysfunction of these genes, considering their known role. Documenting their dysfunction at the cellular level in patient cells enhanced our understanding of biological processes which contribute to the clinical phenotype.
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Affiliation(s)
- Jiadi Wen
- Child and Family Research Institute, Department of Pathology, University of British Columbia, Vancouver, BC, Canada
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Qiao Y, Tyson C, Hrynchak M, Lopez-Rangel E, Hildebrand J, Martell S, Fawcett C, Kasmara L, Calli K, Harvard C, Liu X, Holden JJA, Lewis SME, Rajcan-Separovic E. Clinical application of 2.7M Cytogenetics array for CNV detection in subjects with idiopathic autism and/or intellectual disability. Clin Genet 2012; 83:145-54. [PMID: 22369279 DOI: 10.1111/j.1399-0004.2012.01860.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Higher resolution whole-genome arrays facilitate the identification of smaller copy number variations (CNVs) and their integral genes contributing to autism and/or intellectual disability (ASD/ID). Our study describes the use of one of the highest resolution arrays, the Affymetrix(®) Cytogenetics 2.7M array, coupled with quantitative multiplex polymerase chain reaction (PCR) of short fluorescent fragments (QMPSF) for detection and validation of small CNVs. We studied 82 subjects with ASD and ID in total (30 in the validation and 52 in the application cohort) and detected putatively pathogenic CNVs in 6/52 cases from the application cohort. This included a 130-kb maternal duplication spanning exons 64-79 of the DMD gene which was found in a 3-year-old boy manifesting autism and mild neuromotor delays. Other pathogenic CNVs involved 4p14, 12q24.31, 14q32.31, 15q13.2-13.3, and 17p13.3. We established the optimal experimental conditions which, when applied to select small CNVs for QMPSF confirmation, reduced the false positive rate from 60% to 25%. Our work suggests that selection of small CNVs based on the function of integral genes, followed by review of array experimental parameters resulting in highest confirmation rate using multiplex PCR, may enhance the usefulness of higher resolution platforms for ASD and ID gene discovery.
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Affiliation(s)
- Y Qiao
- BC Child and Family Research Institute, Vancouver, BC, Canada
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Harvard C, Strong E, Mercier E, Colnaghi R, Alcantara D, Chow E, Martell S, Tyson C, Hrynchak M, McGillivray B, Hamilton S, Marles S, Mhanni A, Dawson AJ, Pavlidis P, Qiao Y, Holden JJ, Lewis SME, O'Driscoll M, Rajcan-Separovic E. Understanding the impact of 1q21.1 copy number variant. Orphanet J Rare Dis 2011; 6:54. [PMID: 21824431 PMCID: PMC3180300 DOI: 10.1186/1750-1172-6-54] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2011] [Accepted: 08/08/2011] [Indexed: 01/10/2023] Open
Abstract
Background 1q21.1 Copy Number Variant (CNV) is associated with a highly variable phenotype ranging from congenital anomalies, learning deficits/intellectual disability (ID), to a normal phenotype. Hence, the clinical significance of this CNV can be difficult to evaluate. Here we described the consequences of the 1q21.1 CNV on genome-wide gene expression and function of selected candidate genes within 1q21.1 using cell lines from clinically well described subjects. Methods and Results Eight subjects from 3 families were included in the study: six with a 1q21.1 deletion and two with a 1q21.1 duplication. High resolution Affymetrix 2.7M array was used to refine the 1q21.1 CNV breakpoints and exclude the presence of secondary CNVs of pathogenic relevance. Whole genome expression profiling, studied in lymphoblast cell lines (LBCs) from 5 subjects, showed enrichment of genes from 1q21.1 in the top 100 genes ranked based on correlation of expression with 1q21.1 copy number. The function of two top genes from 1q21.1, CHD1L/ALC1 and PRKAB2, was studied in detail in LBCs from a deletion and a duplication carrier. CHD1L/ALC1 is an enzyme with a role in chromatin modification and DNA damage response while PRKAB2 is a member of the AMP kinase complex, which senses and maintains systemic and cellular energy balance. The protein levels for CHD1L/ALC1 and PRKAB2 were changed in concordance with their copy number in both LBCs. A defect in chromatin remodeling was documented based on impaired decatenation (chromatid untangling) checkpoint (DCC) in both LBCs. This defect, reproduced by CHD1L/ALC1 siRNA, identifies a new role of CHD1L/ALC1 in DCC. Both LBCs also showed elevated levels of micronuclei following treatment with a Topoisomerase II inhibitor suggesting increased DNA breaks. AMP kinase function, specifically in the deletion containing LBCs, was attenuated. Conclusion Our studies are unique as they show for the first time that the 1q21.1 CNV not only causes changes in the expression of its key integral genes, associated with changes at the protein level, but also results in changes in their known function, in the case of AMPK, and newly identified function such as DCC activation in the case of CHD1L/ALC1. Our results support the use of patient lymphoblasts for dissecting the functional sequelae of genes integral to CNVs in carrier cell lines, ultimately enhancing understanding of biological processes which may contribute to the clinical phenotype.
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Affiliation(s)
- Chansonette Harvard
- Child and Family Research Institute, Molecular Cytogenetics and Array Laboratory, 950 West 28th Avenue, Vancouver, BC, Canada
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Dommels YEM, Butts CA, Zhu S, Davy M, Martell S, Hedderley D, Barnett MPG, McNabb WC, Roy NC. Characterization of intestinal inflammation and identification of related gene expression changes in mdr1a(-/-) mice. Genes Nutr 2007; 2:209-23. [PMID: 18850176 DOI: 10.1007/s12263-007-0051-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Accepted: 01/24/2007] [Indexed: 12/31/2022]
Abstract
Multidrug resistance targeted mutation (mdr1a (-/-) ) mice spontaneously develop intestinal inflammation. The aim of this study was to further characterize the intestinal inflammation in mdr1a (-/-) mice. Intestinal samples were collected to measure inflammation and gene expression changes over time. The first signs of inflammation occurred around 16 weeks of age and most mdr1a (-/-) mice developed inflammation between 16 and 27 weeks of age. The total histological injury score was the highest in the colon. The inflammatory lesions were transmural and discontinuous, revealing similarities to human inflammatory bowel diseases (IBD). Genes involved in inflammatory response pathways were up-regulated whereas genes involved in biotransformation and transport were down-regulated in colonic epithelial cell scrapings of inflamed mdra1 (-/-) mice at 25 weeks of age compared to non-inflamed FVB mice. These results show overlap to human IBD and strengthen the use of this in vivo model to study human IBD. The anti-inflammatory regenerating islet-derived genes were expressed at a lower level during inflammation initiation in non-inflamed colonic epithelial cell scrapings of mdr1a (-/-) mice at 12 weeks of age. This result suggests that an insufficiently suppressed immune response could be crucial to the initiation and development of intestinal inflammation in mdr1a (-/-) mice.
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Affiliation(s)
- Y E M Dommels
- Crop & Food Research, Private Bag 11600, Palmerston North, 4442, New Zealand
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15
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Abstract
OBJECTIVES This study aimed to determine whether nitroglycerin (NTG) treatment affects matrix metalloproteinase (MMP) gene expression and activities in human macrophages. BACKGROUND Nitroglycerin is one of the most frequently used therapeutic agents for the symptomatic relief of stable or unstable coronary artery disease; however, its effects on vascular biology are poorly characterized. Despite its powerful vasodilator activity, NTG has not been shown to improve outcomes in coronary disease. We now describe evidence that NTG has potentially pro-inflammatory effects in human monocyte-derived macrophages (MDMs). METHODS Human monocytes were isolated from whole blood by elutriation and allowed to differentiate into macrophages over eight to 10 days. The MDMs were then treated for 4 or 24 h with control media, pharmacologically relevant doses of NTG or other nitric oxide donors. Matrix metalloproteinase activity was measured by zymography, protein levels measured by enzyme-linked immunosorbent assay and messenger ribonucleic acid (mRNA) levels were quantified by competitive reverse transcription-polymerase chain reaction. RESULTS The major MMP expressed by MDMs was MMP-9. Nitroglycerin treatment stimulated a dose-dependent increase in MMP-9 mRNA levels (NTG 200 pmol: 193 +/- 6% and NTG 2,000 pmol: 372 +/- 9% compared to controls, p < 0.005) and MMP-9 activity (NTG 200: 142 +/- 5.5% and NTG 2,000: 167 +/- 11% compared to controls, p < 0.005). Nitroglycerin 2,000 pmol also increased MMP-2 and MMP-7 mRNA levels to 187 +/- 8% and 183 +/- 21% of control values, respectively (p < 0.05). Furthermore, tissue inhibitor of metalloproteinase (TIMP)-1 (the major tissue inhibitor of MMPs) mRNA and protein levels were decreased in NTG 2,000 pmol-treated MDMs compared with control cells (mRNA: 67 +/- 7%, p < 0.005; protein: 45 +/- 5%, p < 0.005). CONCLUSIONS Nitroglycerin in pharmacologically relevant concentrations activates MMP but represses TIMP expression in human macrophages. The subsequent imbalance in MMP/TIMP expression associated with NTG treatment could promote matrix degradation, with potentially adverse effects on plaque stability.
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Affiliation(s)
- Alison K Death
- Department of Medicine, University of Sydney, Sydney, Australia
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