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Silipigni R, Cattaneo E, Baccarin M, Fumagalli M, Bedeschi MF. Rare interstitial deletion of chromosome 2p11.2p12. Report of a new patient with developmental delay and unusual clinical features. Eur J Med Genet 2015; 59:39-42. [PMID: 26700408 DOI: 10.1016/j.ejmg.2015.12.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 12/04/2015] [Accepted: 12/07/2015] [Indexed: 11/16/2022]
Abstract
De novo interstitial deletions of the short arm of chromosome 2 are rare chromosomal abnormalities. Patients showing these kind of microdeletions have developmental delay/intellectual disability, minor facial anomalies including high forehead, frontal bossing, broad nasal bridge, abnormal ears and congenital defects such as skeletal and genital malformations. We describe the second child of a healthy and non consanguineous couple presenting at birth multiple malformations and minor facial anomalies. Because of the clinical findings, an array CGH analysis was performed using Agilent 60K microarray oligonucleotide. The analysis detected a 9.3 Mb deletion on the short arm of chromosome 2 at band p11.2p12 spanning the bases 77,946,599-87,277,610. The five patients previously described display a minimal common deleted region which explains the clinical features shared by all of them, while their individual characteristics might be explained by the different sizes of the deletion. The common deleted region involves several genes (CTNNA2, LRRTM1, REEP1), highly expressed in the nervous system. The deletion found in this case overlaps with most of those reported in literature but our patient displays extra clinical signs such as bilateral choanal atresia and atrial septal defect. It was impossible to find any direct correlation between the genes involved in the deletion and the choanal atresia and the heart defect. The question remains open as to whether these clinical features are a consequence of the deletion or are due to a second pathogenic event. Our case emphasizes the difficulties to find a close correlation between a large deletion and a well defined clinical picture. As only five patients with 2p11.2p12 deletions, reported in the literature are characterized by array CGH, further reports will be necessary to well define a clinical phenotype related to the 2p11.2p12 microdeletion.
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Affiliation(s)
- Rosamaria Silipigni
- Laboratory of Medical Genetics, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
| | - Elisa Cattaneo
- Medical Genetics Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Marco Baccarin
- Laboratory of Medical Genetics, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Monica Fumagalli
- Neonatal Intensive Care Unit, Department of Clinical Science and Community Health, Università degli Studi di Milano and Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
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Evers C, Maas B, Koch KA, Jauch A, Janssen JWG, Sutter C, Parker MJ, Hinderhofer K, Moog U. Mosaic deletion of EXOC6B: further evidence for an important role of the exocyst complex in the pathogenesis of intellectual disability. Am J Med Genet A 2014; 164A:3088-94. [PMID: 25256811 DOI: 10.1002/ajmg.a.36770] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 08/07/2014] [Indexed: 12/21/2022]
Abstract
We describe a boy with developmental delay, speech delay, and minor dysmorphic features with a heterozygous de novo ∼460 kb deletion at 2p13.2 involving only parts of EXOC6B present in about 50% of lymphocytes. This widely expressed gene encodes the exocyst component 6B, which is part of a multiprotein complex required for targeted exocytosis. Little is known about the effect of EXOC6B haploinsufficiency. In 2008, a patient with a complex syndromic phenotype, including left renal agenesis, neutropenia, recurrent pulmonary infections, long bone diaphysis broadening, growth retardation, and developmental delay (DD) was found to carry a de novo translocation t(2;7) involving TSN3 and EXOC6B. Further characterization of the translocation indicated that disruption of TSN3 may be responsible for the skeletal phenotype. Recently, a heterozygous deletion of EXOC6B along with a deletion of the CYP26B1 gene has been reported in a boy with intellectual disability, speech delay, hyperactivity, facial asymmetry, a dysplastic ear, brachycephaly, and mild joint contractures. Additionally, disruption of EXOC6B by a de novo balanced translocation t(2;8) has been described in a patient with developmental delay, epilepsy, autistic and aggressive behavior. This is the first report of a de novo deletion affecting only EXOC6B in an individual with developmental delay. In conclusion, based on our findings and recent data from the literature, there is evidence that EXOC6B and the exocyst complex might play an important role in the molecular pathogenesis of intellectual disability.
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Affiliation(s)
- Christina Evers
- Institute of Human Genetics, Heidelberg University, Heidelberg, Germany
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Hong KW, Kim SS, Kim Y. Genome-wide association study of orthostatic hypotension and supine-standing blood pressure changes in two korean populations. Genomics Inform 2013; 11:129-34. [PMID: 24124408 PMCID: PMC3794085 DOI: 10.5808/gi.2013.11.3.129] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 08/02/2013] [Accepted: 08/06/2013] [Indexed: 12/18/2022] Open
Abstract
Orthostatic hypotension (OH) is defined by a 20-mm Hg difference of systolic blood pressure (dtSBP) and/or a 10-mm Hg difference of diastolic blood pressure (dtDBP) between supine and standing, and OH is associated with a failure of the cardiovascular reflex to maintain blood pressure on standing from a supine position. To understand the underlying genetic factors for OH traits (OH, dtSBP, and dtDBP), genome-wide association studies (GWASs) using 333,651 single nucleotide polymorphisms (SNPs) were conducted separately for two population-based cohorts, Ansung (n = 3,173) and Ansan (n = 3,255). We identified 8 SNPs (5 SNPs for dtSBP and 3 SNPs for dtDBP) that were repeatedly associated in both the Ansung and Ansan cohorts and had p-values of <1 × 10-5 in the meta-analysis. Unfortunately, the SNPs of the OH case control GWAS did not pass our p-value criteria. Four of 8 SNPs were located in the intergenic region of chromosome 2, and the nearest gene (CTNNA2) was located at 1 Mb of distance. CTNNA2 is a linker between cadherin adhesion receptors and the actin cytoskeleton and is essential for stabilizing dendritic spines in rodent hippocampal neurons. Although there is no report about the function in blood pressure regulation, hippocampal neurons interact primarily with the autonomic nervous system and might be related to OH. The remaining SNPs, rs7098785 of dtSBP trait and rs6892553, rs16887217, and rs4959677 of dtDBP trait were located in the PIK3AP1 intron, ACTBL2-3' flanking, STAR intron, and intergenic region, respectively, but there was no clear functional link to blood pressure regulation.
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Affiliation(s)
- Kyung-Won Hong
- Division of Epidemiology and Health Index, Center for Genome Science, Korea National Institute of Health, Korea Centers for Disease Control and Prevention, Cheongwon 363-951, Korea
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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] [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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Rocca MS, Fabretto A, Faletra F, Carlet O, Skabar A, Gasparini P, Pecile V. Contribution of SNP arrays in diagnosis of deletion 2p11.2–p12. Gene 2012; 492:315-8. [DOI: 10.1016/j.gene.2011.10.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 09/30/2011] [Accepted: 10/11/2011] [Indexed: 11/26/2022]
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Tzschach A, Graul-Neumann LM, Konrat K, Richter R, Ebert G, Ullmann R, Neitzel H. Interstitial deletion 2p11.2-p12: Report of a patient with mental retardation and review of the literature. Am J Med Genet A 2009; 149A:242-5. [DOI: 10.1002/ajmg.a.32637] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Seidel J, Heller A, Senger G, Starke H, Chudoba I, Kelbova C, Tönnies H, Neitzel H, Haase C, Beensen V, Zintl F, Claussen U, Liehr T. A multiple translocation event in a patient with hexadactyly, facial dysmorphism, mental retardation and behaviour disorder characterised comprehensively by molecular cytogenetics. Case report and review of the literature. Eur J Pediatr 2003; 162:582-8. [PMID: 12819962 DOI: 10.1007/s00431-003-1254-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2002] [Revised: 04/14/2003] [Accepted: 04/22/2003] [Indexed: 11/30/2022]
Abstract
UNLABELLED We report a 13-year-old female patient with multiple congenital abnormalities (microcephaly, facial dysmorphism, anteverted dysplastic ears and postaxial hexadactyly), mental retardation, and adipose-gigantism. Ultrasonography revealed no signs of a heart defect or renal abnormalities. She showed no speech development and suffered from a behavioural disorder. CNS abnormalities were excluded by cerebral MRI. Initial cytogenetic studies by Giemsa banding revealed an aberrant karyotype involving three chromosomes, t(2;4;11). By high resolution banding and multicolour fluoresence in-situ hybridisation (M-FISH, MCB), chromosome 1 was also found to be involved in the complex chromosomal aberrations, confirming the karyotype 46,XX,t(2;11;4).ish t(1;4;2;11)(q43;q21.1;p12-p13.1;p14.1). To the best of our knowledge no patient has been previously described with such a complex translocation involving 4 chromosomes. This case demonstrates that conventional chromosome banding techniques such as Giemsa banding are not always sufficient to characterise complex chromosomal abnormalities. Only by the additional utilisation of molecular cytogenetic techniques could the complexity of the present chromosomal rearrangements and the origin of the involved chromosomal material be detected. Further molecular genetic studies will be performed to clarify the chromosomal breakpoints potentially responsible for the observed clinical symptoms. CONCLUSION This report demonstrates that multicolour-fluorescence in-situ hybridisation studies should be performed in patients with congenital abnormalities and suspected aberrant karyotypes in addition to conventional Giemsa banding.
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Affiliation(s)
- Jörg Seidel
- Department of Paediatrics, Friedrich-Schiller University, Kochstrasse 2, 07740 Jena, Germany.
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Lacbawan FL, White BJ, Anguiano A, Rigdon DT, Ball KD, Bromage GB, Yang X, DiFazio MP, Levin SW. Rare interstitial deletion (2)(p11.2p13) in a child with pericentric inversion (2)(p11.2q13) of paternal origin. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1096-8628(19991119)87:2<139::aid-ajmg5>3.0.co;2-j] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
We report on an infant with a karyotype of 46,XY,del(2) (p11.2p13), the fourth reported case in the literature. At birth, the child had eventration of the diaphragm. His phenotype was suggestive of a connective tissue disorder with scoliosis, pectus carinatum, long slender fingers, camptodactyly, cryptorchidism, hypertonia and myopia. His facial appearance was mildly dysmorphic and strongly resembled a previously reported patient with the same deletion. The child expired at 2 months of age. Some generalizations can be made about the phenotype for del(2)(p11.2p13), despite reporting of cases at different ages.
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Affiliation(s)
- S L Wenger
- Department of Pediatrics, University of Pittsburgh, Children's Hospital of Pittsburgh, PA, USA
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