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Gupta S, Fahiminiya S, Wang T, Dempsey Nunez L, Rosenblatt DS, Gibson WT, Gilfix B, Bergeron JJM, Jerome-Majewska LA. Somatic overgrowth associated with homozygous mutations in both MAN1B1 and SEC23A. Cold Spring Harb Mol Case Stud 2016; 2:a000737. [PMID: 27148587 PMCID: PMC4853519 DOI: 10.1101/mcs.a000737] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Using whole-exome sequencing, we identified homozygous mutations in two unlinked genes, SEC23A c.1200G>C (p.M400I) and MAN1B1 c.1000C>T (p.R334C), associated with congenital birth defects in two patients from a consanguineous family. Patients presented with carbohydrate-deficient transferrin, tall stature, obesity, macrocephaly, and maloccluded teeth. The parents were healthy heterozygous carriers for both mutations and an unaffected sibling with tall stature carried the heterozygous mutation in SEC23A only. Mutations in SEC23A are responsible for craniolenticosultura dysplasia (CLSD). CLSD patients are short, have late-closing fontanels, and have reduced procollagen (pro-COL1A1) secretion because of abnormal pro-COL1A1 retention in the endoplasmic reticulum (ER). The mutation we identified in MAN1B1 was previously associated with reduced MAN1B1 protein and congenital disorders of glycosylation (CDG). CDG patients are also short, are obese, and have abnormal glycan remodeling. Molecular analysis of fibroblasts from the family revealed normal levels of SEC23A in all cells and reduced levels of MAN1B1 in cells with heterozygous or homozygous mutations in SEC23A and MAN1B1. Secretion of pro-COL1A1 was increased in fibroblasts from the siblings and patients, and pro-COL1A1 was retained in Golgi of heterozygous and homozygous mutant cells, although intracellular pro-COL1A1 was increased in patient fibroblasts only. We postulate that increased pro-COL1A1 secretion is responsible for tall stature in these patients and an unaffected sibling, and not previously discovered in patients with mutations in either SEC23A or MAN1B1. The patients in this study share biochemical and cellular characteristics consistent with mutations in MAN1B1 and SEC23A, indicating a digenic disease.
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Affiliation(s)
- Swati Gupta
- Department of Human Genetics, McGill University, Montreal, Quebec H3A 1B1, Canada
| | - Somayyeh Fahiminiya
- Department of Human Genetics, McGill University, Montreal, Quebec H3A 1B1, Canada
| | - Tracy Wang
- Department of Human Genetics, McGill University, Montreal, Quebec H3A 1B1, Canada
| | - Laura Dempsey Nunez
- Department of Human Genetics, McGill University, Montreal, Quebec H3A 1B1, Canada
| | - David S Rosenblatt
- Department of Human Genetics, McGill University, Montreal, Quebec H3A 1B1, Canada;; Department of Pediatrics, McGill University, Montreal, Quebec H4A 3J1, Canada
| | - William T Gibson
- Department of Medical Genetics, Child and Family Research Institute, Vancouver, British Columbia V6H 3V4, Canada
| | - Brian Gilfix
- Department of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
| | - John J M Bergeron
- Department of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
| | - Loydie A Jerome-Majewska
- Department of Human Genetics, McGill University, Montreal, Quebec H3A 1B1, Canada;; Department of Pediatrics, McGill University, Montreal, Quebec H4A 3J1, Canada;; Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
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Yu HC, Coughlin CR, Geiger EA, Salvador BJ, Elias ER, Cavanaugh JL, Chatfield KC, Miyamoto SD, Shaikh TH. Discovery of a potentially deleterious variant in TMEM87B in a patient with a hemizygous 2q13 microdeletion suggests a recessive condition characterized by congenital heart disease and restrictive cardiomyopathy. Cold Spring Harb Mol Case Stud 2016; 2:a000844. [PMID: 27148590 PMCID: PMC4853521 DOI: 10.1101/mcs.a000844] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 02/03/2016] [Indexed: 01/22/2023] Open
Abstract
Restrictive cardiomyopathy (RCM) is a rare cause of heart muscle disease with the highest mortality rate among cardiomyopathy types. The etiology of RCM is poorly understood, although genetic causes have been implicated, and syndromic associations have been described. Here, we describe a patient with an atrial septal defect and restrictive cardiomyopathy along with craniofacial anomalies and intellectual disabilities. Initial screening using chromosomal microarray analysis (CMA) identified a maternally inherited 2q13 microdeletion. The patient had many of the features reported in previous cases with the recurrent 2q13 microdeletion syndrome. However, the inheritance of the microdeletion from an unaffected mother combined with the low incidence (10%) and milder forms of cardiac defects in previously reported cases made the clinical significance of the CMA results unclear. Whole-exome sequencing (WES) with trio-based analysis was performed and identified a paternally inherited TMEM87B mutation (c.1366A>G, p.Asn456Asp) in the patient. TMEM87B, a highly conserved, transmembrane protein of currently unknown function, lies within the critical region of the recurrent 2q13 microdeletion syndrome. Furthermore, a recent study had demonstrated that depletion of TMEM87B in zebrafish embryos affected cardiac development and led to cardiac hypoplasia. Thus, by combining CMA and WES, we potentially uncover an autosomal-recessive disorder characterized by a severe cardiac phenotype caused by mutations in TMEM87B. This study expands the spectrum of phenotypes associated with the recurrent 2q13 microdeletion syndrome and also further suggests the role of TMEM87B in its etiology, especially the cardiac pathology.
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Affiliation(s)
- Hung-Chun Yu
- Department of Pediatrics, Section of Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Curtis R Coughlin
- Department of Pediatrics, Section of Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Elizabeth A Geiger
- Department of Pediatrics, Section of Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Blake J Salvador
- Department of Pediatrics, Section of Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Ellen R Elias
- Department of Pediatrics, Section of Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Jean L Cavanaugh
- Department of Pediatrics, Division of Cardiology, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Kathryn C Chatfield
- Department of Pediatrics, Division of Cardiology, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Shelley D Miyamoto
- Department of Pediatrics, Division of Cardiology, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Tamim H Shaikh
- Department of Pediatrics, Section of Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA;; Colorado Intellectual and Developmental Disabilities Research Center (IDDRC), University of Colorado School of Medicine, Aurora, Colorado 80045, USA
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The Identification of Microdeletion and Reciprocal Microduplication in 22q11.2 Using High-Resolution CMA Technology. BIOMED RESEARCH INTERNATIONAL 2016; 2016:7415438. [PMID: 27123452 PMCID: PMC4830712 DOI: 10.1155/2016/7415438] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 03/13/2016] [Indexed: 01/05/2023]
Abstract
The chromosome 22q11.2 region has long been implicated in genomic diseases. Some genomic regions exhibit numerous low copy repeats with high identity in which they provide increased genomic instability and mediate deletions and duplications in many disorders. DiGeorge Syndrome is the most common deletion syndrome and reciprocal duplications could be occurring in half of the frequency of microdeletions. We described five patients with phenotypic variability that carries deletions or reciprocal duplications at 22q11.2 detected by Chromosomal Microarray Analysis. The CytoScan HD technology was used to detect changes in the genome copy number variation of patients who had clinical indication to global developmental delay and a normal karyotype. We observed in our study three microdeletions and two microduplications in 22q11.2 region with variable intervals containing known genes and unstudied transcripts as well as the LCRs that are often flanking and within this genomic rearrangement. The identification of these variants is of particular interest because it may provide insight into genes or genomic regions that are crucial for specific phenotypic manifestations and are useful to assist in the quest for understanding the mechanisms subjacent to genomic deletions and duplications.
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A catalog of hemizygous variation in 127 22q11 deletion patients. Hum Genome Var 2016; 3:15065. [PMID: 27274857 PMCID: PMC4892188 DOI: 10.1038/hgv.2015.65] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 10/30/2015] [Accepted: 11/02/2015] [Indexed: 02/06/2023] Open
Abstract
The 22q11.2 deletion syndrome is the most common microdeletion disorder, with wide phenotypic variability. To investigate variation within the non-deleted allele we performed targeted resequencing of the 22q11.2 region for 127 patients, identifying multiple deletion sizes, including two deletions with atypical breakpoints. We cataloged ~12,000 hemizygous variant positions, of which 84% were previously annotated. Within the coding regions 95 non-synonymous variants, three stop gains, and two frameshift insertions were identified, some of which we speculate could contribute to atypical phenotypes. We also catalog tolerability of 22q11 gene mutations based on related autosomal recessive disorders in man, embryonic lethality in mice, cross-species conservation and observations that some genes harbor more or less variants than expected. This extensive catalog of hemizygous variants will serve as a blueprint for future experiments to correlate 22q11DS variation with phenotype.
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Schiller SA, Seebode C, Wieser GL, Goebbels S, Möbius W, Horowitz M, Sarig O, Sprecher E, Emmert S. Establishment of Two Mouse Models for CEDNIK Syndrome Reveals the Pivotal Role of SNAP29 in Epidermal Differentiation. J Invest Dermatol 2015; 136:672-679. [PMID: 26747696 DOI: 10.1016/j.jid.2015.12.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 04/29/2015] [Accepted: 06/03/2015] [Indexed: 12/26/2022]
Abstract
Loss-of-function mutations in the synaptosomal-associated protein 29 (SNAP29) gene cause the cerebral dysgenesis, neuropathy, ichthyosis, and keratoderma syndrome. In this study, we created total (Snap29(-/-)) as well as keratinocyte-specific (Snap29(fl/fl)/K14-Cre) Snap29 knockout mice. Both mutant mice exhibited a congenital distinct ichthyotic phenotype resulting in neonatal lethality. Mutant mice revealed acanthosis and hyperkeratosis as well as abnormal keratinocyte differentiation and increased proliferation. In addition, the epidermal barrier was severely impaired. These results indicate an essential role of SNAP29 in epidermal differentiation and barrier formation. Markedly decreased deposition of lamellar body contents in mutant mice epidermis and the observation of malformed lamellar bodies indicate severe impairments in lamellar body function due to the Snap29 knockout. We also found increased microtubule associated protein-1 light chain 3, isoform B-II levels, unchanged p62/SQSTM1 protein amounts, and strong induction of the endoplasmic reticulum stress marker C/EBP homologous protein in mutant mice. This emphasizes a role of SNAP29 in autophagy and endoplasmic reticulum stress. Our murine models serve as powerful tools for investigating keratinocyte differentiation processes and provide insights into the essential contribution of SNAP29 to epidermal differentiation.
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Affiliation(s)
- Stina A Schiller
- Department of Dermatology, Venereology and Allergology, University Medical Center Goettingen, Goettingen, Germany
| | - Christina Seebode
- Department of Dermatology, Venereology and Allergology, University Medical Center Goettingen, Goettingen, Germany; Clinic for Dermatology and Venereology, University Medical Center Rostock, Rostock, Germany
| | - Georg L Wieser
- Department of Neurogenetics, Max-Planck-Institute for Experimental Medicine, Goettingen, Germany
| | - Sandra Goebbels
- Department of Neurogenetics, Max-Planck-Institute for Experimental Medicine, Goettingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max-Planck-Institute for Experimental Medicine, Goettingen, Germany
| | - Mia Horowitz
- Department of Cell Research and Immunology, Tel Aviv University, Tel Aviv, Israel
| | - Ofer Sarig
- Department of Dermatology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Eli Sprecher
- Department of Dermatology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Steffen Emmert
- Department of Dermatology, Venereology and Allergology, University Medical Center Goettingen, Goettingen, Germany; Clinic for Dermatology and Venereology, University Medical Center Rostock, Rostock, Germany.
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Boycott KM, Beaulieu CL, Kernohan KD, Gebril OH, Mhanni A, Chudley AE, Redl D, Qin W, Hampson S, Küry S, Tetreault M, Puffenberger EG, Scott JN, Bezieau S, Reis A, Uebe S, Schumacher J, Hegele RA, McLeod DR, Gálvez-Peralta M, Majewski J, Ramaekers VT, Nebert DW, Innes AM, Parboosingh JS, Abou Jamra R. Autosomal-Recessive Intellectual Disability with Cerebellar Atrophy Syndrome Caused by Mutation of the Manganese and Zinc Transporter Gene SLC39A8. Am J Hum Genet 2015; 97:886-93. [PMID: 26637978 DOI: 10.1016/j.ajhg.2015.11.002] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 11/03/2015] [Indexed: 12/17/2022] Open
Abstract
Manganese (Mn) and zinc (Zn) are essential divalent cations used by cells as protein cofactors; various human studies and animal models have demonstrated the importance of Mn and Zn for development. Here we describe an autosomal-recessive disorder in six individuals from the Hutterite community and in an unrelated Egyptian sibpair; the disorder is characterized by intellectual disability, developmental delay, hypotonia, strabismus, cerebellar atrophy, and variable short stature. Exome sequencing in one affected Hutterite individual and the Egyptian family identified the same homozygous variant, c.112G>C (p.Gly38Arg), affecting a conserved residue of SLC39A8. The affected Hutterite and Egyptian individuals did not share an extended common haplotype, suggesting that the mutation arose independently. SLC39A8 is a member of the solute carrier gene family known to import Mn, Zn, and other divalent cations across the plasma membrane. Evaluation of these two metal ions in the affected individuals revealed variably low levels of Mn and Zn in blood and elevated levels in urine, indicating renal wasting. Our findings identify a human Mn and Zn transporter deficiency syndrome linked to SLC39A8, providing insight into the roles of Mn and Zn homeostasis in human health and development.
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Affiliation(s)
- Kym M Boycott
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON K1H 8L1, Canada.
| | - Chandree L Beaulieu
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON K1H 8L1, Canada
| | - Kristin D Kernohan
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON K1H 8L1, Canada
| | - Ola H Gebril
- National Research Centre, El Bohoth Street, Dokki, Giza 12622, Egypt
| | - Aziz Mhanni
- Section of Genetics and Metabolism, Children's Hospital and the Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, MB R3A 1S1, Canada
| | - Albert E Chudley
- Section of Genetics and Metabolism, Children's Hospital and the Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, MB R3A 1S1, Canada
| | - David Redl
- Department of Medical Genetics, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Wen Qin
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON K1H 8L1, Canada
| | - Sarah Hampson
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON K1H 8L1, Canada
| | - Sébastien Küry
- Department of Medical Genetics, CHU Nantes, Nantes 44093, France
| | - Martine Tetreault
- Department of Human Genetics, McGill University, Montreal, QC H3A 1B1, Canada
| | | | - James N Scott
- Department of Radiology, Foothills Hospital, Calgary, AB T2N 2T9, Canada
| | - Stéphane Bezieau
- Department of Medical Genetics, CHU Nantes, Nantes 44093, France
| | - André Reis
- Institute of Human Genetics, FAU Erlangen-Nürnberg, Erlangen 91054, Germany
| | - Steffen Uebe
- Institute of Human Genetics, FAU Erlangen-Nürnberg, Erlangen 91054, Germany
| | | | - Robert A Hegele
- Robarts Research Institute and University of Western Ontario, London, ON N6A 5B7, Canada
| | - D Ross McLeod
- Department of Medical Genetics, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Marina Gálvez-Peralta
- Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Jacek Majewski
- Department of Human Genetics, McGill University, Montreal, QC H3A 1B1, Canada
| | - Vincent T Ramaekers
- Department of Paediatric Neurology, Centre Hospitalier Universitaire, Liege 4032, Belgium
| | - Daniel W Nebert
- Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA; Department of Pediatrics & Molecular Developmental Biology, Division of Human Genetics, Cincinnati Children's Hospital, Cincinnati, OH 45229, USA
| | - A Micheil Innes
- Department of Medical Genetics, University of Calgary, Calgary, AB T2N 4N1, Canada
| | | | - Rami Abou Jamra
- Institute of Human Genetics, FAU Erlangen-Nürnberg, Erlangen 91054, Germany.
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Abstract
Genetic skin diseases, or genodermatoses, often have extracutaneous manifestations. Ocular manifestations in particular can have significant clinical implications, like blindness. Other manifestations, such as the corneal opacities that occur in X-linked ichthyosis, are asymptomatic but characteristic of a particular genodermatosis. Ophthalmologic examination can aid in diagnosis when characteristic findings are seen. The genodermatoses with ocular manifestations will be reviewed, but neurocutaneous, syndromes, genetic pigmentary disorders, and genetic metabolic diseases are not included because they are covered elsewhere in this issue.
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Affiliation(s)
- Melinda Jen
- Section of Pediatric Dermatology, Children's Hospital of Philadelphia; Departments of Pediatrics and Dermatology, Perelman School of Medicine at the University of Pennsylvania, 3550 Market St, Second floor, Philadelphia, PA, 19104.
| | - Sudha Nallasamy
- The Vision Center, Children's Hospital Los Angeles; Department of Ophthalmology, Keck School of Medicine, University of Southern California, 4650 Sunset Blvd, MS #88, Los Angeles, CA, 90027
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Williams CM, Savage JS, Harper MT, Moore SF, Hers I, Poole AW. Identification of roles for the SNARE-associated protein, SNAP29, in mouse platelets. Platelets 2015; 27:286-94. [PMID: 26587753 DOI: 10.3109/09537104.2015.1100282] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Platelets are critical for maintaining vascular hemostasis, but also play a major role in the formation of occlusive cardiovascular and cerebrovascular thrombi under disease conditions. Secretion of platelet alpha and dense granules is a requirement for efficient thrombus formation. Understanding and targeting the mechanisms of secretion is important to aid the development of effective antithrombotics. SNAP29 is a tSNARE found in platelets, but whose role has not been defined. Using a platelet-specific SNAP29 knockout mouse model, we assessed the role of SNAP29 in platelet secretion and function under standardized conditions and also in in vitro and in vivo thrombosis. The data showed no major defects in SNAP29-null platelets, but revealed a minor defect in α-granule secretion and a significant increase in embolization rate of thrombi in vivo. These data suggest that SNAP29 contributes to the regulation of platelet α-granule secretion and thrombus stability, possibly partially masked by functional redundancy with other tSNAREs, such as SNAP23.
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Affiliation(s)
- C M Williams
- a School of Physiology & Pharmacology , University of Bristol , Bristol , UK
| | - J S Savage
- a School of Physiology & Pharmacology , University of Bristol , Bristol , UK.,b Cancer Research UK Clinical Trials Unit (CRCTU), School of Cancer Sciences , University of Birmingham , Edgbaston, Birmingham , UK
| | - M T Harper
- a School of Physiology & Pharmacology , University of Bristol , Bristol , UK.,c Department of Pharmacology , University of Cambridge , Cambridge , UK
| | - S F Moore
- a School of Physiology & Pharmacology , University of Bristol , Bristol , UK
| | - I Hers
- a School of Physiology & Pharmacology , University of Bristol , Bristol , UK
| | - A W Poole
- a School of Physiology & Pharmacology , University of Bristol , Bristol , UK
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Abstract
22q11.2 deletion syndrome (22q11.2DS) is the most common chromosomal microdeletion disorder, estimated to result mainly from de novo non-homologous meiotic recombination events occurring in approximately 1 in every 1,000 fetuses. The first description in the English language of the constellation of findings now known to be due to this chromosomal difference was made in the 1960s in children with DiGeorge syndrome, who presented with the clinical triad of immunodeficiency, hypoparathyroidism and congenital heart disease. The syndrome is now known to have a heterogeneous presentation that includes multiple additional congenital anomalies and later-onset conditions, such as palatal, gastrointestinal and renal abnormalities, autoimmune disease, variable cognitive delays, behavioural phenotypes and psychiatric illness - all far extending the original description of DiGeorge syndrome. Management requires a multidisciplinary approach involving paediatrics, general medicine, surgery, psychiatry, psychology, interventional therapies (physical, occupational, speech, language and behavioural) and genetic counselling. Although common, lack of recognition of the condition and/or lack of familiarity with genetic testing methods, together with the wide variability of clinical presentation, delays diagnosis. Early diagnosis, preferably prenatally or neonatally, could improve outcomes, thus stressing the importance of universal screening. Equally important, 22q11.2DS has become a model for understanding rare and frequent congenital anomalies, medical conditions, psychiatric and developmental disorders, and may provide a platform to better understand these disorders while affording opportunities for translational strategies across the lifespan for both patients with 22q11.2DS and those with these associated features in the general population.
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Márquez-Ávila CS, Vizcaíno-Alarcón A, García-Delgado C, Núñez-Martínez PM, Flores-Ramírez F, Reyes-de la Rosa ADP, Mendelsberg-Fishbein P, Ibarra-Grajeda D, Medina-Bravo P, Balderrábano-Saucedo N, Esteva-Solsona S, Márquez-Quiróz LDC, Flores-Cuevas A, Sánchez-Urbina R, Morales-Jiménez AB, Garibay-Nieto N, Del Bosque-Garza J, Pietropaolo-Cienfuegos D, Gutiérrez-Camacho C, García-Morales L, Morán-Barroso VF. Velocardiofacial syndrome in Mexican patients: Unusually high prevalence of congenital heart disease. Int J Pediatr Otorhinolaryngol 2015; 79:1886-91. [PMID: 26409294 DOI: 10.1016/j.ijporl.2015.08.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Revised: 08/24/2015] [Accepted: 08/27/2015] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Velocardiofacial syndrome (VCFS) is the most common microdeletion syndrome with an incidence of 1:4000 live births. Its phenotype is highly variable with facial, velopharyngeal, cardiac, endocrine, immunologic and psychiatric abnormalities. It is caused by a microdeletion in chromosome 22q11.2. OBJECTIVES We present 7 years of experience evaluating patients with VCFS regarding their main clinical characteristics. MATERIAL AND METHODS The patients included were multidisciplinary evaluated and had a positive FISH analysis for del22q11.2. RESULTS A total of 62 patients were assessed, a 34 female/28 male ratio was observed with ages ranging from 9 days to 16 years, all but one patient had typical facial features. A diagnosis of congenital heart disease was established in 97% of the patients; other clinical characteristics were identified with different percentages such as cleft palate, and hypocalcaemia. Three cases had a familial presentation. DISCUSSION While the clinical findings of this study were in general terms in keeping with the literature, it is interesting the unexpectedly high percentage of congenital heart disease identified in Mexican children with VCFS that also was the main cause for clinical referral.
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Affiliation(s)
- Candy Sue Márquez-Ávila
- Department of Audiology and Phoniatrics, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Alfredo Vizcaíno-Alarcón
- Department of Cardiology, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Constanza García-Delgado
- Department of Genetics, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Paulina María Núñez-Martínez
- Department of Genetics, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Francisco Flores-Ramírez
- Department of Genetics, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Alejandra del Pilar Reyes-de la Rosa
- Department of Genetics, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Paola Mendelsberg-Fishbein
- Department of Genetics, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Diana Ibarra-Grajeda
- Department of Audiology and Phoniatrics, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Patricia Medina-Bravo
- Department of Endocrinology, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Norma Balderrábano-Saucedo
- Department of Cardiology, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Salvador Esteva-Solsona
- Department of Endocrinology, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Luz del Carmen Márquez-Quiróz
- Department of Genetics, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Arturo Flores-Cuevas
- Department of Genetics, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Rocío Sánchez-Urbina
- Department of Genetics, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Ariadna Berenice Morales-Jiménez
- Department of Genetics, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Nayely Garibay-Nieto
- Department of Endocrinology, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Jesús Del Bosque-Garza
- Department of Psychiatrics, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Dino Pietropaolo-Cienfuegos
- Department of Allergy and Inmunology, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Claudia Gutiérrez-Camacho
- Department of Education, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Leticia García-Morales
- Department of Endocrinology, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
| | - Verónica Fabiola Morán-Barroso
- Department of Genetics, Hospital Infantil de México Federico Gómez, Calle Dr. Márquez 162, Colonia Doctores, Delegación Cuauhtémoc, C.P. 06720, Mexico City, Mexico.
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61
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Faden M, AlZahrani F, Mendoza-Londono R, Dupuis L, Hartley T, Kannu P, Raiman J, Howard A, Qin W, Tetreault M, Xi J, Al-Thamer I, Maas R, Boycott K, Alkuraya F, Alkuraya FS. Identification of a Recognizable Progressive Skeletal Dysplasia Caused by RSPRY1 Mutations. Am J Hum Genet 2015; 97:608-15. [PMID: 26365341 DOI: 10.1016/j.ajhg.2015.08.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 08/10/2015] [Indexed: 02/02/2023] Open
Abstract
Skeletal dysplasias are highly variable Mendelian phenotypes. Molecular diagnosis of skeletal dysplasias is complicated by their extreme clinical and genetic heterogeneity. We describe a clinically recognizable autosomal-recessive disorder in four affected siblings from a consanguineous Saudi family, comprising progressive spondyloepimetaphyseal dysplasia, short stature, facial dysmorphism, short fourth metatarsals, and intellectual disability. Combined autozygome/exome analysis identified a homozygous frameshift mutation in RSPRY1 with resulting nonsense-mediated decay. Using a gene-centric "matchmaking" system, we were able to identify a Peruvian simplex case subject whose phenotype is strikingly similar to the original Saudi family and whose exome sequencing had revealed a likely pathogenic homozygous missense variant in the same gene. RSPRY1 encodes a hypothetical RING and SPRY domain-containing protein of unknown physiological function. However, we detect strong RSPRY1 protein localization in murine embryonic osteoblasts and periosteal cells during primary endochondral ossification, consistent with a role in bone development. This study highlights the role of gene-centric matchmaking tools to establish causal links to genes, especially for rare or previously undescribed clinical entities.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Fowzan S Alkuraya
- Department of Genetics, King Faisal and Research Center, Riyadh 11211, Saudi Arabia; Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia.
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62
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Balan S, Iwayama Y, Toyota T, Toyoshima M, Maekawa M, Yoshikawa T. 22q11.2 deletion carriers and schizophrenia-associated novel variants. Br J Psychiatry 2015; 204:398-9. [PMID: 24482440 DOI: 10.1192/bjp.bp.113.138420] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The penetrance of schizophrenia risk in carriers of the 22q11.2 deletion is high but incomplete, suggesting the possibility of additional genetic defects. We performed whole exome sequencing on two individuals with 22q11.2 deletion, one with schizophrenia and the other who was psychosis-free. The results revealed novel genetic variants related to neuronal function exclusively in the person with schizophrenia (frameshift: KAT8, APOH and SNX31; nonsense: EFCAB11 and CLVS2). This study paves the way towards a more complete understanding of variant dose and genetic architecture in schizophrenia.
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Affiliation(s)
- S Balan
- S. Balan, PhD, Y. Iwayama, MS, T. Toyota, MD, PhD, M. Toyoshima, PhD, M. Maekawa, MD, PhD, T. Yoshikawa, MD, PhD, Laboratory for Molecular Psychiatry, RIKEN Brain Science Institute, Saitama, Japan
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63
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Whole-Genome Sequencing Suggests Schizophrenia Risk Mechanisms in Humans with 22q11.2 Deletion Syndrome. G3-GENES GENOMES GENETICS 2015; 5:2453-61. [PMID: 26384369 PMCID: PMC4632064 DOI: 10.1534/g3.115.021345] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Chromosome 22q11.2 microdeletions impart a high but incomplete risk for schizophrenia. Possible mechanisms include genome-wide effects of DGCR8 haploinsufficiency. In a proof-of-principle study to assess the power of this model, we used high-quality, whole-genome sequencing of nine individuals with 22q11.2 deletions and extreme phenotypes (schizophrenia, or no psychotic disorder at age >50 years). The schizophrenia group had a greater burden of rare, damaging variants impacting protein-coding neurofunctional genes, including genes involved in neuron projection (nominal P = 0.02, joint burden of three variant types). Variants in the intact 22q11.2 region were not major contributors. Restricting to genes affected by a DGCR8 mechanism tended to amplify between-group differences. Damaging variants in highly conserved long intergenic noncoding RNA genes also were enriched in the schizophrenia group (nominal P = 0.04). The findings support the 22q11.2 deletion model as a threshold-lowering first hit for schizophrenia risk. If applied to a larger and thus better-powered cohort, this appears to be a promising approach to identify genome-wide rare variants in coding and noncoding sequence that perturb gene networks relevant to idiopathic schizophrenia. Similarly designed studies exploiting genetic models may prove useful to help delineate the genetic architecture of other complex phenotypes.
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64
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Poot M, Haaf T. Mechanisms of Origin, Phenotypic Effects and Diagnostic Implications of Complex Chromosome Rearrangements. Mol Syndromol 2015; 6:110-34. [PMID: 26732513 DOI: 10.1159/000438812] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/23/2015] [Indexed: 01/08/2023] Open
Abstract
Complex chromosome rearrangements (CCRs) are currently defined as structural genome variations that involve more than 2 chromosome breaks and result in exchanges of chromosomal segments. They are thought to be extremely rare, but their detection rate is rising because of improvements in molecular cytogenetic technology. Their population frequency is also underestimated, since many CCRs may not elicit a phenotypic effect. CCRs may be the result of fork stalling and template switching, microhomology-mediated break-induced repair, breakage-fusion-bridge cycles, or chromothripsis. Patients with chromosomal instability syndromes show elevated rates of CCRs due to impaired DNA double-strand break responses during meiosis. Therefore, the putative functions of the proteins encoded by ATM, BLM, WRN, ATR, MRE11, NBS1, and RAD51 in preventing CCRs are discussed. CCRs may exert a pathogenic effect by either (1) gene dosage-dependent mechanisms, e.g. haploinsufficiency, (2) mechanisms based on disruption of the genomic architecture, such that genes, parts of genes or regulatory elements are truncated, fused or relocated and thus their interactions disturbed - these mechanisms will predominantly affect gene expression - or (3) mixed mutation mechanisms in which a CCR on one chromosome is combined with a different type of mutation on the other chromosome. Such inferred mechanisms of pathogenicity need corroboration by mRNA sequencing. Also, future studies with in vitro models, such as inducible pluripotent stem cells from patients with CCRs, and transgenic model organisms should substantiate current inferences regarding putative pathogenic effects of CCRs. The ramifications of the growing body of information on CCRs for clinical and experimental genetics and future treatment modalities are briefly illustrated with 2 cases, one of which suggests KDM4C (JMJD2C) as a novel candidate gene for mental retardation.
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Affiliation(s)
- Martin Poot
- Department of Human Genetics, University of Würzburg, Würzburg, Germany
| | - Thomas Haaf
- Department of Human Genetics, University of Würzburg, Würzburg, Germany
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65
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Hladilkova E, Barøy T, Fannemel M, Vallova V, Misceo D, Bryn V, Slamova I, Prasilova S, Kuglik P, Frengen E. A recurrent deletion on chromosome 2q13 is associated with developmental delay and mild facial dysmorphisms. Mol Cytogenet 2015; 8:57. [PMID: 26236398 PMCID: PMC4521466 DOI: 10.1186/s13039-015-0157-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 07/05/2015] [Indexed: 11/24/2022] Open
Abstract
We report two unrelated patients with overlapping chromosome 2q13 deletions (patient 1 in chr2:111415137-113194067 bp and patient 2 in chr2:110980342-113007823 bp, hg 19). Patient 1 presents with developmental delay, microcephaly and mild dysmorphic facial features, and patient 2 with autism spectrum disorder, borderline cognitive abilities, deficits in attention and executive functions and mild dysmorphic facial features. The mother and maternal grandmother of patient 1 were healthy carriers of the deletion. Previously, 2q13 deletions were reported in 27 patients, and the interpretation of its clinical significance varied. Our findings support that the 2q13 deletion is associated with a developmental delay syndrome manifesting with variable expressivity and reduced penetrance which poses a challenge for genetic counselling as well as the clinical recognition of 2q13 deletion patients.
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Affiliation(s)
- Eva Hladilkova
- Department of Medical Genetics, University of Oslo and Oslo University Hospital, P.O.Box 1036, Blindern, N-0315 Oslo, Norway.,Department of Medical Genetics, University Hospital, Children Medical Hospital, Brno, Czech Republic
| | - Tuva Barøy
- Department of Medical Genetics, University of Oslo and Oslo University Hospital, P.O.Box 1036, Blindern, N-0315 Oslo, Norway
| | - Madeleine Fannemel
- Department of Medical Genetics, University of Oslo and Oslo University Hospital, P.O.Box 1036, Blindern, N-0315 Oslo, Norway
| | - Vladimira Vallova
- Department of Medical Genetics, University Hospital, Children Medical Hospital, Brno, Czech Republic.,Department of Genetics and Molecular Biology, Institute of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno - Bohunice, Czech Republic
| | - Doriana Misceo
- Department of Medical Genetics, University of Oslo and Oslo University Hospital, P.O.Box 1036, Blindern, N-0315 Oslo, Norway
| | - Vesna Bryn
- Department of Habilitation, Sykehuset Innlandet HF, Lillehammer, Norway
| | - Iva Slamova
- Department of Genetics and Molecular Biology, Institute of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno - Bohunice, Czech Republic.,Sanatorium Helios ltd., Laboratory of Medical Genetics, Brno, Czech Republic
| | - Sarka Prasilova
- Department of Medical Genetics, University Hospital, Children Medical Hospital, Brno, Czech Republic
| | - Petr Kuglik
- Department of Medical Genetics, University Hospital, Children Medical Hospital, Brno, Czech Republic.,Department of Genetics and Molecular Biology, Institute of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno - Bohunice, Czech Republic
| | - Eirik Frengen
- Department of Medical Genetics, University of Oslo and Oslo University Hospital, P.O.Box 1036, Blindern, N-0315 Oslo, Norway
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66
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Chung JH, Cai J, Suskin BG, Zhang Z, Coleman K, Morrow BE. Whole-Genome Sequencing and Integrative Genomic Analysis Approach on Two 22q11.2 Deletion Syndrome Family Trios for Genotype to Phenotype Correlations. Hum Mutat 2015; 36:797-807. [PMID: 25981510 DOI: 10.1002/humu.22814] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 05/01/2015] [Indexed: 12/20/2022]
Abstract
The 22q11.2 deletion syndrome (22q11DS) affects 1:4,000 live births and presents with highly variable phenotype expressivity. In this study, we developed an analytical approach utilizing whole-genome sequencing (WGS) and integrative analysis to discover genetic modifiers. Our pipeline combined available tools in order to prioritize rare, predicted deleterious, coding and noncoding single-nucleotide variants (SNVs), and insertion/deletions from WGS. We sequenced two unrelated probands with 22q11DS, with contrasting clinical findings, and their unaffected parents. Proband P1 had cognitive impairment, psychotic episodes, anxiety, and tetralogy of Fallot (TOF), whereas proband P2 had juvenile rheumatoid arthritis but no other major clinical findings. In P1, we identified common variants in COMT and PRODH on 22q11.2 as well as rare potentially deleterious DNA variants in other behavioral/neurocognitive genes. We also identified a de novo SNV in ADNP2 (NM_014913.3:c.2243G>C), encoding a neuroprotective protein that may be involved in behavioral disorders. In P2, we identified a novel nonsynonymous SNV in ZFPM2 (NM_012082.3:c.1576C>T), a known causative gene for TOF, which may act as a protective variant downstream of TBX1, haploinsufficiency of which is responsible for congenital heart disease in individuals with 22q11DS.
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Affiliation(s)
- Jonathan H Chung
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York
| | - Jinlu Cai
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Barrie G Suskin
- Department of Obstetrics & Gynecology and Women's Health, Montefiore Medical Center, Bronx, New York
| | - Zhengdong Zhang
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York
| | - Karlene Coleman
- Children's Healthcare of Atlanta at Egleston, Atlanta, Georgia
| | - Bernice E Morrow
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York
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67
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Mendoza-Londono R, Fahiminiya S, Majewski J, Tétreault M, Nadaf J, Kannu P, Sochett E, Howard A, Stimec J, Dupuis L, Roschger P, Klaushofer K, Palomo T, Ouellet J, Al-Jallad H, Mort J, Moffatt P, Boudko S, Bächinger HP, Rauch F, Rauch F. Recessive osteogenesis imperfecta caused by missense mutations in SPARC. Am J Hum Genet 2015; 96:979-85. [PMID: 26027498 DOI: 10.1016/j.ajhg.2015.04.021] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 04/28/2015] [Indexed: 11/26/2022] Open
Abstract
Secreted protein, acidic, cysteine-rich (SPARC) is a glycoprotein that binds to collagen type I and other proteins in the extracellular matrix. Using whole-exome sequencing to identify the molecular defect in two unrelated girls with severe bone fragility and a clinical diagnosis of osteogenesis imperfecta type IV, we identified two homozygous variants in SPARC (GenBank: NM_003118.3; c.497G>A [p.Arg166His] in individual 1; c.787G>A [p.Glu263Lys] in individual 2). Published modeling and site-directed mutagenesis studies had previously shown that the residues substituted by these mutations form an intramolecular salt bridge in SPARC and are essential for the binding of SPARC to collagen type I. The amount of SPARC secreted by skin fibroblasts was reduced in individual 1 but appeared normal in individual 2. The migration of collagen type I alpha chains produced by these fibroblasts was mildly delayed on SDS-PAGE gel, suggesting some overmodification of collagen during triple helical formation. Pulse-chase experiments showed that collagen type I secretion was mildly delayed in skin fibroblasts from both individuals. Analysis of an iliac bone sample from individual 2 showed that trabecular bone was hypermineralized on the material level. In conclusion, these observations show that homozygous mutations in SPARC can give rise to severe bone fragility in humans.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Frank Rauch
- Shriners Hospital for Children, Montréal, QC H3G 1A6, Canada.
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68
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Swillen A, McDonald-McGinn D. Developmental trajectories in 22q11.2 deletion. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2015; 169:172-81. [PMID: 25989227 DOI: 10.1002/ajmg.c.31435] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Chromosome 22q11.2 deletion syndrome (22q11.2DS), a neurogenetic condition, is the most common microdeletion syndrome affecting 1 in 2,000-4,000 live births and involving haploinsufficiency of ∼50 genes resulting in a multisystem disorder. Phenotypic expression is highly variable and ranges from severe life-threatening conditions to only a few associated features. Most common medical problems include: congenital heart disease, in particular conotruncal anomalies; palatal abnormalities, most frequently velopharyngeal incompetence (VPI); immunodeficiency; hypocalcemia due to hypoparathyroidism; genitourinary anomalies; severe feeding/gastrointestinal differences; and subtle dysmorphic facial features. The neurocognitive profile is also highly variable, both between individuals and during the course of development. From infancy onward, motor delays (often with hypotonia) and speech/language deficits are commonly observed. During the preschool and primary school ages, learning difficulties are very common. The majority of patients with 22q11.2DS have an intellectual level that falls in the borderline range (IQ 70-84), and about one-third have mild to moderate intellectual disability. More severe levels of intellectual disability are uncommon in children and adolescents but are more frequent in adults. Individuals with 22q11.2DS are at an increased risk for developing several psychiatric disorders including attention deficit with hyperactivity disorder (ADHD), autism spectrum disorder (ASD), anxiety and mood disorders, and psychotic disorders and schizophrenia. In this review, we will focus on the developmental phenotypic transitions regarding cognitive development in 22q11.2DS from early preschool to adulthood, and on the changing behavioral/psychiatric phenotype across age, on a background of frequently complex medical conditions.
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69
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Ben-Salem S, Nara S, Al-Shamsi AM, Valle D, Ali BR, Al-Gazali L. New Arab family with cerebral dysgenesis, neuropathy, ichthyosis and keratoderma syndrome suggests a possible founder effect for the c.223delG mutation. J Dermatol 2015; 42:821-2. [PMID: 25958742 DOI: 10.1111/1346-8138.12917] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Salma Ben-Salem
- Department of Pathology, College of Medicine and Heath Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Sobreira Nara
- Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Aisha M Al-Shamsi
- Department of Pediatrics, Tawam Hospital, Al-Ain, United Arab Emirates
| | - David Valle
- Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Bassam R Ali
- Department of Pathology, College of Medicine and Heath Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Lihadh Al-Gazali
- Department of Pediatrics, College of Medicine and Heath Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
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70
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Ben-Omran T, Fahiminiya S, Sorfazlian N, Almuriekhi M, Nawaz Z, Nadaf J, Abu Khadija K, Zaineddin S, Kamel H, Majewski J, Tropepe V. Nonsense mutation in theWDR73gene is associated with Galloway-Mowat syndrome. J Med Genet 2015; 52:381-90. [DOI: 10.1136/jmedgenet-2014-102707] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 03/22/2015] [Indexed: 01/10/2023]
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71
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Pagnamenta AT, Howard MF, Wisniewski E, Popitsch N, Knight SJL, Keays DA, Quaghebeur G, Cox H, Cox P, Balla T, Taylor JC, Kini U. Germline recessive mutations in PI4KA are associated with perisylvian polymicrogyria, cerebellar hypoplasia and arthrogryposis. Hum Mol Genet 2015; 24:3732-41. [PMID: 25855803 PMCID: PMC4459391 DOI: 10.1093/hmg/ddv117] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 04/03/2015] [Indexed: 01/06/2023] Open
Abstract
Polymicrogyria (PMG) is a structural brain abnormality involving the cerebral cortex that results from impaired neuronal migration and although several genes have been implicated, many cases remain unsolved. In this study, exome sequencing in a family where three fetuses had all been diagnosed with PMG and cerebellar hypoplasia allowed us to identify regions of the genome for which both chromosomes were shared identical-by-descent, reducing the search space for causative variants to 8.6% of the genome. In these regions, the only plausibly pathogenic mutations were compound heterozygous variants in PI4KA, which Sanger sequencing confirmed segregated consistent with autosomal recessive inheritance. The paternally transmitted variant predicted a premature stop mutation (c.2386C>T; p.R796X), whereas the maternally transmitted variant predicted a missense substitution (c.5560G>A; p.D1854N) at a conserved residue within the catalytic domain. Functional studies using expressed wild-type or mutant PI4KA enzyme confirmed the importance of p.D1854 for kinase activity. Our results emphasize the importance of phosphoinositide signalling in early brain development.
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Affiliation(s)
- Alistair T Pagnamenta
- National Institute for Health Research Biomedical Research Centre, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Malcolm F Howard
- National Institute for Health Research Biomedical Research Centre, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Eva Wisniewski
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD 20892, USA
| | - Niko Popitsch
- National Institute for Health Research Biomedical Research Centre, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Samantha J L Knight
- National Institute for Health Research Biomedical Research Centre, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - David A Keays
- Institute of Molecular Pathology, Vienna 1030, Austria
| | | | - Helen Cox
- West Midlands Regional Clinical Genetics Service, Clinical Genetics Unit and
| | - Phillip Cox
- Department of Histopathology, Birmingham Women's Hospital NHS Foundation Trust, Birmingham B15 2TG, UK
| | - Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jenny C Taylor
- National Institute for Health Research Biomedical Research Centre, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Usha Kini
- Department of Clinical Genetics, Oxford University Hospitals NHS Trust, Oxford OX3 9DU, UK,
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72
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Almuriekhi M, Shintani T, Fahiminiya S, Fujikawa A, Kuboyama K, Takeuchi Y, Nawaz Z, Nadaf J, Kamel H, Kitam AK, Samiha Z, Mahmoud L, Ben-Omran T, Majewski J, Noda M. Loss-of-Function Mutation in APC2 Causes Sotos Syndrome Features. Cell Rep 2015; 10:1585-1598. [PMID: 25753423 DOI: 10.1016/j.celrep.2015.02.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 01/14/2015] [Accepted: 01/31/2015] [Indexed: 01/24/2023] Open
Abstract
Sotos syndrome, characterized by intellectual disability and characteristic facial features, is caused by haploinsufficiency in the NSD1 gene. We conducted an etiological study on two siblings with Sotos features without mutations in NSD1 and detected a homozygous frameshift mutation in the APC2 gene by whole-exome sequencing, which resulted in the loss of function of cytoskeletal regulation in neurons. Apc2-deficient (Apc2-/-) mice exhibited impaired learning and memory abilities along with an abnormal head shape. Endogenous Apc2 expression was downregulated by the knockdown of Nsd1, indicating that APC2 is a downstream effector of NSD1 in neurons. Nsd1 knockdown in embryonic mouse brains impaired the migration and laminar positioning of cortical neurons, as observed in Apc2-/- mice, and this defect was rescued by the forced expression of Apc2. Thus, APC2 is a crucial target of NSD1, which provides an explanation for the intellectual disability associated with Sotos syndrome.
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Affiliation(s)
- Mariam Almuriekhi
- Section of Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, P.O. Box 3050, Doha, Qatar
| | - Takafumi Shintani
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki 444-8787, Japan; School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8787, Japan
| | - Somayyeh Fahiminiya
- Department of Human Genetics, Faculty of Medicine, McGill University, Montreal, QC H3A 1B1, Canada; McGill University and Génome Québec Innovation Centre, Montreal, QC H3A 0G1, Canada
| | - Akihiro Fujikawa
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki 444-8787, Japan
| | - Kazuya Kuboyama
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki 444-8787, Japan
| | - Yasushi Takeuchi
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki 444-8787, Japan
| | - Zafar Nawaz
- Cytogenetic and Molecular Cytogenetic Laboratory, Department of Laboratory Medicine and Pathology, Hamad Medical Corporation, P.O. Box 3050, Doha, Qatar
| | - Javad Nadaf
- Department of Human Genetics, Faculty of Medicine, McGill University, Montreal, QC H3A 1B1, Canada; McGill University and Génome Québec Innovation Centre, Montreal, QC H3A 0G1, Canada
| | - Hussein Kamel
- Department of Radiology, Hamad Medical Corporation, P.O. Box 3050, Doha, Qatar
| | - Abu Khadija Kitam
- Cytogenetic and Molecular Cytogenetic Laboratory, Department of Laboratory Medicine and Pathology, Hamad Medical Corporation, P.O. Box 3050, Doha, Qatar
| | - Zaineddin Samiha
- Cytogenetic and Molecular Cytogenetic Laboratory, Department of Laboratory Medicine and Pathology, Hamad Medical Corporation, P.O. Box 3050, Doha, Qatar
| | - Laila Mahmoud
- Section of Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, P.O. Box 3050, Doha, Qatar
| | - Tawfeg Ben-Omran
- Section of Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, P.O. Box 3050, Doha, Qatar
| | - Jacek Majewski
- Department of Human Genetics, Faculty of Medicine, McGill University, Montreal, QC H3A 1B1, Canada; McGill University and Génome Québec Innovation Centre, Montreal, QC H3A 0G1, Canada
| | - Masaharu Noda
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki 444-8787, Japan; School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8787, Japan.
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73
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Cole-Carpenter syndrome is caused by a heterozygous missense mutation in P4HB. Am J Hum Genet 2015; 96:425-31. [PMID: 25683117 DOI: 10.1016/j.ajhg.2014.12.027] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 12/29/2014] [Indexed: 11/21/2022] Open
Abstract
Cole-Carpenter syndrome is a severe bone fragility disorder that is characterized by frequent fractures, craniosynostosis, ocular proptosis, hydrocephalus, and distinctive facial features. To identify the cause of Cole-Carpenter syndrome in the two individuals whose clinical results were presented in the original description of this disorder, we performed whole-exome sequencing of genomic DNA samples from both individuals. The two unrelated individuals had the same heterozygous missense mutation in exon 9 of P4HB (NM_000918.3: c.1178A>G [p.Tyr393Cys]), the gene that encodes protein disulfide isomerase (PDI). In one individual, the P4HB mutation had arisen de novo, whereas in the other the mutation was transmitted from the clinically unaffected father who was a mosaic carrier of the variant. The mutation was located in the C-terminal disulfide isomerase domain of PDI, sterically close to the enzymatic center, and affected disulfide isomerase activity in vitro. Skin fibroblasts showed signs of increased endoplasmic reticulum stress, but despite the reported importance of PDI for collagen type I production, the rate of collagen type I secretion appeared normal. In conclusion, Cole-Carpenter syndrome is caused by a specific de novo mutation in P4HB that impairs the disulfide isomerase activity of PDI.
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74
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Kloosterman WP, Hochstenbach R. Deciphering the pathogenic consequences of chromosomal aberrations in human genetic disease. Mol Cytogenet 2014; 7:100. [PMID: 25606056 PMCID: PMC4299681 DOI: 10.1186/s13039-014-0100-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 12/08/2014] [Indexed: 01/14/2023] Open
Abstract
Chromosomal aberrations include translocations, deletions, duplications, inversions, aneuploidies and complex rearrangements. They underlie genetic disease in roughly 15% of patients with multiple congenital abnormalities and/or mental retardation (MCA/MR). In genetic diagnostics, the pathogenicity of chromosomal aberrations in these patients is typically assessed based on criteria such as phenotypic similarity to other patients with the same or overlapping aberration, absence in healthy individuals, de novo occurrence, and protein coding gene content. However, a thorough understanding of the molecular mechanisms that lead to MCA/MR as a result of chromosome aberrations is often lacking. Chromosome aberrations can affect one or more genes in a complex manner, such as by changing the regulation of gene expression, by disrupting exons, and by creating fusion genes. The precise delineation of breakpoints by whole-genome sequencing enables the construction of local genomic architecture and facilitates the prediction of the molecular determinants of the patient's phenotype. Here, we review current methods for breakpoint identification and their impact on the interpretation of chromosome aberrations in patients with MCA/MR. In addition, we discuss opportunities to dissect disease mechanisms based on large-scale genomic technologies and studies in model organisms.
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Affiliation(s)
- Wigard P Kloosterman
- Department of Medical Genetics, Center for Molecular Medicine, University Medical Center Utrecht, P.O. Box 85060, 3508 AB Utrecht, The Netherlands
| | - Ron Hochstenbach
- Department of Medical Genetics, Genome Diagnostics, P.O. Box 85090, 3508 AB Utrecht, The Netherlands
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75
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Leoni C, Stevenson DA, Geiersbach KB, Paxton CN, Krock BL, Mao R, Rope AF. Neural tube defects and atypical deletion on 22q11.2. Am J Med Genet A 2014; 164A:2701-6. [PMID: 25123577 DOI: 10.1002/ajmg.a.36701] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 06/20/2014] [Indexed: 11/07/2022]
Abstract
The 22q11.2 deletion syndrome (22q11.2DS) is a common microdeletion disorder. Most of the patients show the common 3 Mb deletion but proximal 1.5 Mb deletion and unusual deletions located outside the common deleted region, have been detected particularly with the advance of comparative cytogenomic microarray technologies. The individuals reported in the literature with unusual deletions involving the 22q11 region, showed milder facial phenotypes, decreased incidence of cardiac anomalies, and intellectual disability. We describe two sibs with an atypical 0.8 Mb microdeletion of chromosome 22q11 who both showed myelomeningocele and mild facial dysmorphisms. The association between neural tube defect and the clinical diagnosis of Di George anomaly/velocardiofacial syndrome is well documented in the literature, but not all cases had molecular studies to determine breakpoint regions. This report helps to narrow a potential critical region for neural tube defects associated with 22q11 deletions.
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Affiliation(s)
- Chiara Leoni
- Center for Rare Diseases, Departments of Pediatrics, Catholic University, Rome, Italy; University of Utah, Department of Pediatrics, Division of Medical Genetics, Salt Lake City, Utah
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76
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Gos M, Fahiminiya S, Poznański J, Klapecki J, Obersztyn E, Piotrowicz M, Wierzba J, Posmyk R, Bal J, Majewski J. Contribution of RIT1 mutations to the pathogenesis of Noonan syndrome: four new cases and further evidence of heterogeneity. Am J Med Genet A 2014; 164A:2310-6. [PMID: 24939608 DOI: 10.1002/ajmg.a.36646] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 05/21/2014] [Indexed: 11/11/2022]
Affiliation(s)
- Monika Gos
- Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland
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77
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Watson CT, Marques-Bonet T, Sharp AJ, Mefford HC. The genetics of microdeletion and microduplication syndromes: an update. Annu Rev Genomics Hum Genet 2014; 15:215-244. [PMID: 24773319 DOI: 10.1146/annurev-genom-091212-153408] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Chromosomal abnormalities, including microdeletions and microduplications, have long been associated with abnormal developmental outcomes. Early discoveries relied on a common clinical presentation and the ability to detect chromosomal abnormalities by standard karyotype analysis or specific assays such as fluorescence in situ hybridization. Over the past decade, the development of novel genomic technologies has allowed more comprehensive, unbiased discovery of microdeletions and microduplications throughout the human genome. The ability to quickly interrogate large cohorts using chromosome microarrays and, more recently, next-generation sequencing has led to the rapid discovery of novel microdeletions and microduplications associated with disease, including very rare but clinically significant rearrangements. In addition, the observation that some microdeletions are associated with risk for several neurodevelopmental disorders contributes to our understanding of shared genetic susceptibility for such disorders. Here, we review current knowledge of microdeletion/duplication syndromes, with a particular focus on recurrent rearrangement syndromes.
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Affiliation(s)
- Corey T Watson
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Tomas Marques-Bonet
- Institut de Biologia Evolutiva, Universitat Pompeu Fabra/CSIC, 08003 Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain.,Centro Nacional de Análisis Genómico, 08023 Barcelona, Spain
| | - Andrew J Sharp
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Heather C Mefford
- Department of Pediatrics, University of Washington, Seattle, Washington 98195
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78
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Czeschik JC, Hehr U, Hartmann B, Lüdecke HJ, Rosenbaum T, Schweiger B, Wieczorek D. 160 kb deletion in ISPD unmasking a recessive mutation in a patient with Walker–Warburg syndrome. Eur J Med Genet 2013; 56:689-94. [DOI: 10.1016/j.ejmg.2013.09.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 09/30/2013] [Indexed: 01/03/2023]
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79
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Srebniak MI, Diderich KEM, Govaerts LCP, Joosten M, Riedijk S, Galjaard RJH, Van Opstal D. Types of array findings detectable in cytogenetic diagnosis: a proposal for a generic classification. Eur J Hum Genet 2013; 22:856-8. [PMID: 24193341 DOI: 10.1038/ejhg.2013.254] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
| | - Karin E M Diderich
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Marieke Joosten
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Sam Riedijk
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Diane Van Opstal
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
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80
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Fahiminiya S, Almuriekhi M, Nawaz Z, Staffa A, Lepage P, Ali R, Hashim L, Schwartzentruber J, Abu Khadija K, Zaineddin S, Gamal H, Majewski J, Ben-Omran T. Whole exome sequencing unravels disease-causing genes in consanguineous families in Qatar. Clin Genet 2013; 86:134-41. [PMID: 24102521 DOI: 10.1111/cge.12280] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 08/16/2013] [Accepted: 09/12/2013] [Indexed: 01/02/2023]
Abstract
Whole exome sequencing (WES) has greatly facilitated the identification of causal mutations for diverse human genetic disorders. We applied WES as a molecular diagnostic tool to identify disease-causing genes in consanguineous families in Qatar. Seventeen consanguineous families with diverse disorders were recruited. Initial mutation screening of known genes related to the clinical diagnoses did not reveal the causative mutations. Using WES approach, we identified the definitive disease-causing mutations in four families: (i) a novel nonsense homozygous (c.1034C>G) in PHKG2 causing glycogen storage disease type 9C (GSD9C) in a male with initial diagnosis of GSD3; (ii) a novel homozygous 1-bp deletion (c.915del) in NSUN2 in a male proband with Noonan-like syndrome; (iii) a homozygous SNV (c.1598C>G) in exon 11 of IDUA causing Hurler syndrome in a female proband with unknown clinical diagnosis; (iv) a de novo known splicing mutation (c.1645+1G>A) in PHEX in a female proband with initial diagnosis of autosomal recessive hypophosphatemic rickets. Applying WES as a diagnostic tool led to the unambiguous identification of disease-causing mutations in phenotypically complex disorders or correction of the initial clinical diagnosis in ˜25% of our cases.
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Affiliation(s)
- S Fahiminiya
- Department of Human Genetics, Faculty of Medicine, McGill University and Genome Quebec Innovation Center, Montreal, Quebec, Canada
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81
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Rojnueangnit K, Robin NH. Craniosynostosis and radial ray defect: a rare presentation of 22q11.2 deletion syndrome. Am J Med Genet A 2013; 161A:2024-6. [PMID: 23813949 DOI: 10.1002/ajmg.a.36004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 03/31/2013] [Indexed: 11/06/2022]
Abstract
A newborn with bilateral coronal craniosynostosis, hypoplastic thumbs, imperforate anus, and prenatal growth restriction was evaluated and given the clinical diagnosis of Baller-Gerold syndrome (BGS). While confirmatory testing of RECQL4 was pending, the infant developed unexplained hypocalcemia, prompting testing for a 22q11.2 deletion. Subsequently, the infant was found to have a 22q11.2 deletion, and was negative for an RECQL4 mutation. We therefore conclude that 22q11.2 deletion syndrome can present with findings resembling the BGS phenotype.
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Affiliation(s)
- Kitiwan Rojnueangnit
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL 35294-0024, USA
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82
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Genetic insights into the functional elements of language. Hum Genet 2013; 132:959-86. [PMID: 23749164 DOI: 10.1007/s00439-013-1317-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 05/22/2013] [Indexed: 12/11/2022]
Abstract
Language disorders cover a wide range of conditions with heterologous and overlapping phenotypes and complex etiologies harboring both genetic and environmental influences. Genetic approaches including the identification of genes linked to speech and language phenotypes and the characterization of normal and aberrant functions of these genes have, in recent years, unraveled complex details of molecular and cognitive mechanisms and provided valuable insight into the biological foundations of language. Consistent with this approach, we have reviewed the functional aspects of allelic variants of genes which are currently known to be either causally associated with disorders of speech and language or impact upon the spectrum of normal language ability. We have also reviewed candidate genes associated with heritable speech and language disorders. In addition, we have evaluated language phenotypes and associated genetic components in developmental syndromes that, together with a spectrum of altered language abilities, manifest various phenotypes and offer details of multifactorial determinants of language function. Data from this review have revealed a predominance of regulatory networks involved in the control of differentiation and functioning of neurons, neuronal tracks and connections among brain structures associated with both cognitive and language faculties. Our findings, furthermore, have highlighted several multifactorial determinants in overlapping speech and language phenotypes. Collectively this analysis has revealed an interconnected developmental network and a close association of the language faculty with cognitive functions, a finding that has the potential to provide insight into linguistic hypotheses defining in particular, the contribution of genetic elements to and the modular nature of the language faculty.
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83
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Carvill GL, Mefford HC. Microdeletion syndromes. Curr Opin Genet Dev 2013; 23:232-9. [PMID: 23664828 DOI: 10.1016/j.gde.2013.03.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 03/11/2013] [Accepted: 03/25/2013] [Indexed: 01/11/2023]
Abstract
The recent explosion in the implementation of genome-wide microarray technology to discover rare, pathogenic genomic rearrangements in a variety of diseases has led to the discovery of numerous microdeletion syndromes. It is now clear that these microdeletions are associated with extensive phenotypic heterogeneity and incomplete penetrance. A subset of recurrent microdeletions underpin diverse phenotypes, including intellectual disability, autism, epilepsy and neuropsychiatric disorders. Recent studies highlight a role for additional low frequency variants, or 'second hits' to account for this variability. The implementation of massively parallel sequencing and epigenetic models may provide a powerful prospective approach to the delineation of microdeletion syndrome phenotypes.
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Affiliation(s)
- Gemma L Carvill
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA 98195, USA
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