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Beyltjens T, Boudin E, Revencu N, Boeckx N, Bertrand M, Schütz L, Haack TB, Weber A, Biliouri E, Vinkšel M, Zagožen A, Peterlin B, Pai S, Telegrafi A, Henderson LB, Ells C, Turner L, Wuyts W, Van Hul W, Hendrickx G, Mortier GR. Heterozygous pathogenic variants involving CBFB cause a new skeletal disorder resembling cleidocranial dysplasia. J Med Genet 2022; 60:498-504. [PMID: 36241386 PMCID: PMC10176335 DOI: 10.1136/jmg-2022-108739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 09/03/2022] [Indexed: 11/03/2022]
Abstract
BACKGROUND Cleidocranial dysplasia (CCD) is a rare skeletal dysplasia with significant clinical variability. Patients with CCD typically present with delayed closure of fontanels and cranial sutures, dental anomalies, clavicular hypoplasia or aplasia and short stature. Runt-related transcription factor 2 (RUNX2) is currently the only known disease-causing gene for CCD, but several studies have suggested locus heterogeneity. METHODS The cohort consists of eight subjects from five unrelated families partially identified through GeneMatcher. Exome or genome sequencing was applied and in two subjects the effect of the variant was investigated at RNA level. RESULTS In each subject a heterozygous pathogenic variant in CBFB was detected, whereas no genomic alteration involving RUNX2 was found. Three CBFB variants (one splice site alteration, one nonsense variant, one 2 bp duplication) were shown to result in a premature stop codon. A large intragenic deletion was found to delete exon 4, without affecting CBFB expression. The effect of a second splice site variant could not be determined but most likely results in a shortened or absent protein. Affected individuals showed similarities with RUNX2-related CCD, including dental and clavicular abnormalities. Normal stature and neurocognitive problems were however distinguishing features. CBFB encodes the core-binding factor β subunit, which can interact with all RUNX proteins (RUNX1, RUNX2, RUNX3) to form heterodimeric transcription factors. This may explain the phenotypic differences between CBFB-related and RUNX2-related CCD. CONCLUSION We confirm the previously suggested locus heterogeneity for CCD by identifying five pathogenic variants in CBFB in a cohort of eight individuals with clinical and radiographic features reminiscent of CCD.
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Affiliation(s)
- Tessi Beyltjens
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium
| | - Eveline Boudin
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium
| | - Nicole Revencu
- Center for Human Genetics, Cliniques universitaires Saint-Luc and University of Louvain, Brussels, Belgium
| | - Nele Boeckx
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium
| | - Miriam Bertrand
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Leon Schütz
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Tobias B Haack
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Axel Weber
- Institute of Human Genetics, Justus Liebig University, Giessen, Germany
| | - Eleni Biliouri
- Institute of Human Genetics, Justus Liebig University, Giessen, Germany
| | - Mateja Vinkšel
- Clinical Institute of Genomic Medicine, University Medical Centre Ljubljana Division of Internal Medicine, Ljubljana, Slovenia
| | - Anja Zagožen
- Clinical Institute of Genomic Medicine, University Medical Centre Ljubljana Division of Internal Medicine, Ljubljana, Slovenia
| | - Borut Peterlin
- Clinical Institute of Genomic Medicine, University Medical Centre Ljubljana Division of Internal Medicine, Ljubljana, Slovenia
| | - Shashidhar Pai
- Children's Health, Division of Genetics, Medical University of South Carolina, Charleston, South Carolina, USA
| | | | | | - Courtney Ells
- Provincial Medical Genetics Program, Eastern Health, St. John's, Newfoundland, Canada
| | - Lesley Turner
- Provincial Medical Genetics Program, Eastern Health, St. John's, Newfoundland, Canada.,Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Wim Wuyts
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium
| | - Wim Van Hul
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium
| | - Gretl Hendrickx
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium .,Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Geert R Mortier
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium.,Department of Human Genetics, KU Leuven, Leuven, Belgium.,Center for Human Genetics, University Hospital Leuven, Leuven, Belgium
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Lengyel A, Pinti É, Eggermann T, Fekete G, Haltrich I. Deletion of 16q22.2q23.3 in a Boy with a Phenotype Reminiscent of Silver-Russell Syndrome. Mol Syndromol 2021; 12:300-304. [PMID: 34602957 DOI: 10.1159/000515941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/16/2021] [Indexed: 11/19/2022] Open
Abstract
A 15-month-old boy presented with growth and global developmental delay, feeding difficulties, sleep disturbance and several minor anomalies, including a large anterior fontanel, relative macrocephaly, and a triangular face. Clinical suspicion prompted genetic investigations for Silver-Russell syndrome and related disorders. SNP array analysis led to the diagnosis of an approximately 10-Mb large deletion of the long arm in chromosome 16q22.2q23.3. Interstitial deletions of 16q show a wide variability of related features; however, considering the differences in size and location of the deletions in the known patients, the phenotypic overlap is surprising. Here, we report a novel microdeletion, compare the proband with data from scientific literature and international databases, and discuss possible diagnostic implications.
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Affiliation(s)
- Anna Lengyel
- 2nd Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Éva Pinti
- 2nd Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Thomas Eggermann
- Institute of Human Genetics, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - György Fekete
- 2nd Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Irén Haltrich
- 2nd Department of Pediatrics, Semmelweis University, Budapest, Hungary
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3
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Henslee G, Williams CL, Liu P, Bertuch AA. Identification and characterization of novel ACD variants: modulation of TPP1 protein level offsets the impact of germline loss-of-function variants on telomere length. Cold Spring Harb Mol Case Stud 2021; 7:a005454. [PMID: 33446513 PMCID: PMC7903889 DOI: 10.1101/mcs.a005454] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 02/04/2021] [Indexed: 12/13/2022] Open
Abstract
Telomere biology disorders, largely characterized by telomere lengths below the first centile for age, are caused by variants in genes associated with telomere replication, structure, or function. One of these genes, ACD, which encodes the shelterin protein TPP1, is associated with both autosomal dominantly and autosomal recessively inherited telomere biology disorders. TPP1 recruits telomerase to telomeres and stimulates telomerase processivity. Several studies probing the effect of various synthetic or patient-derived variants have mapped specific residues and regions of TPP1 that are important for interaction with TERT, the catalytic component of telomerase. However, these studies have come to differing conclusions regarding ACD haploinsufficiency. Here, we report a proband with compound heterozygous novel variants in ACD (NM_001082486.1)-c.505_507delGAG, p.(Glu169del); and c.619delG, p.(Asp207Thrfs*22)-and a second proband with a heterozygous chromosomal deletion encompassing ACD: arr[hg19] 16q22.1(67,628,846-67,813,408)x1. Clinical data, including symptoms and telomere length within the pedigrees, suggested that loss of one ACD allele was insufficient to induce telomere shortening or confer clinical features. Further analyses of lymphoblastoid cell lines showed decreased nascent ACD RNA and steady-state mRNA, but normal TPP1 protein levels, in cells containing heterozygous ACD c.619delG, p.(Asp207Thrfs*22), or the ACD-encompassing chromosomal deletion compared to controls. Based on our results, we conclude that cells are able to compensate for loss of one ACD allele by activating a mechanism to maintain TPP1 protein levels, thus maintaining normal telomere length.
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Affiliation(s)
- Gabrielle Henslee
- Baylor College of Medicine, Integrated Molecular and Biomedical Sciences Graduate Program, Houston, Texas 77030, USA
- Baylor College of Medicine, Department of Pediatrics, Hematology/Oncology, Houston, Texas 77030, USA
- Texas Children's Hospital, Cancer and Hematology Centers, Houston, Texas 77030, USA
| | - Christopher L Williams
- Baylor College of Medicine, Department of Pediatrics, Hematology/Oncology, Houston, Texas 77030, USA
- Texas Children's Hospital, Cancer and Hematology Centers, Houston, Texas 77030, USA
| | - Pengfei Liu
- Baylor College of Medicine, Department of Molecular and Human Genetics, Houston, Texas 77030, USA
- Baylor Genetics, Houston, Texas 77021, USA
| | - Alison A Bertuch
- Baylor College of Medicine, Integrated Molecular and Biomedical Sciences Graduate Program, Houston, Texas 77030, USA
- Baylor College of Medicine, Department of Pediatrics, Hematology/Oncology, Houston, Texas 77030, USA
- Texas Children's Hospital, Cancer and Hematology Centers, Houston, Texas 77030, USA
- Baylor College of Medicine, Department of Molecular and Human Genetics, Houston, Texas 77030, USA
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Abdullah S, Helal M, Dupuis L, Stavropoulos DJ, Louro P, Ramos L, Mendoza-Londono R. 16q22.1 microdeletion and anticipatory guidance. Am J Med Genet A 2019; 179:1287-1292. [PMID: 31141312 DOI: 10.1002/ajmg.a.61155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 02/10/2019] [Accepted: 02/11/2019] [Indexed: 11/08/2022]
Abstract
The widespread availability of comparative genomic hybridization (CGH) array analysis has led to the discovery of several genomic microdeletion-associated syndromes and has identified possible genetic causes for patients with previously unexplained clinical features. We report the case of four unrelated patients who share common clinical characteristics, namely failure to thrive, developmental delay, dysmorphic features, and congenital anomalies. CGH array analysis revealed that all four patients had a de novo microdeletion at 16q22.1. In this case report, we describe the clinical features of these patients and offer possible explanations for how their 16q22.1 microdeletion may account for their symptoms. We also suggest guidelines for the management of 16q22.1 microdeletion based on the phenotypes seen in our patients and the function of the genes affected by this microdeletion.
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Affiliation(s)
- Sarah Abdullah
- Undergraduate Medical Education, Queen's University School of Medicine, Kingston, Ontario, Canada
| | - Mayada Helal
- Division of Clinical and Metabolic Genetics, The Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada
| | - Lucie Dupuis
- Division of Clinical and Metabolic Genetics, The Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada
| | - D James Stavropoulos
- Department of Pediatric Laboratory Medicine, The Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada
| | - Pedro Louro
- Medical Genetics Unit, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Lina Ramos
- Medical Genetics Unit, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Roberto Mendoza-Londono
- Division of Clinical and Metabolic Genetics, The Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada
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5
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Contribution of copy number variants (CNVs) to congenital, unexplained intellectual and developmental disabilities in Lebanese patients. Mol Cytogenet 2015; 8:26. [PMID: 25922617 PMCID: PMC4411788 DOI: 10.1186/s13039-015-0130-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 03/23/2015] [Indexed: 11/10/2022] Open
Abstract
Background Chromosomal microarray analysis (CMA) is currently the most widely adopted clinical test for patients with unexplained intellectual disability (ID), developmental delay (DD), and congenital anomalies. Its use has revealed the capacity to detect copy number variants (CNVs), as well as regions of homozygosity, that, based on their distribution on chromosomes, indicate uniparental disomy or parental consanguinity that is suggestive of an increased probability of recessive disease. Results We screened 149 Lebanese probands with ID/DD and 99 healthy controls using the Affymetrix Cyto 2.7 M and SNP6.0 arrays. We report all identified CNVs, which we divided into groups. Pathogenic CNVs were identified in 12.1% of the patients. We review the genotype/phenotype correlation in a patient with a 1q44 microdeletion and refine the minimal critical regions responsible for the 10q26 and 16q monosomy syndromes. Several likely causative CNVs were also detected, including new homozygous microdeletions (9p23p24.1, 10q25.2, and 8p23.1) in 3 patients born to consanguineous parents, involving potential candidate genes. However, the clinical interpretation of several other CNVs remains uncertain, including a microdeletion affecting ATRNL1. This CNV of unknown significance was inherited from the patient’s unaffected-mother; therefore, additional ethnically matched controls must be screened to obtain enough evidence for classification of this CNV. Conclusion This study has provided supporting evidence that whole-genome analysis is a powerful method for uncovering chromosomal imbalances, regardless of consanguinity in the parents of patients and despite the challenge presented by analyzing some CNVs. Electronic supplementary material The online version of this article (doi:10.1186/s13039-015-0130-y) contains supplementary material, which is available to authorized users.
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6
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Genesio R, Ronga V, Castelluccio P, Fioretti G, Mormile A, Leone G, Conti A, Cavaliere ML, Nitsch L. Pure 16q21q22.1 deletion in a complex rearrangement possibly caused by a chromothripsis event. Mol Cytogenet 2013; 6:29. [PMID: 23915422 PMCID: PMC3737039 DOI: 10.1186/1755-8166-6-29] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 05/31/2013] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Partial monosomies of chromosome 16q are rare and overlapping effects from complex chromosomal rearrangements often hamper genotype-phenotype correlations for such imbalances. Here, we report the clinical features of an isolated partial monosomy 16q21q22.1 in a boy with a complex de novo rearrangement possibly resulting from a chromothripsis event. RESULTS The patient presented with low birth weight, microcephaly, developmental delay, facial dysmorphisms, short stature, dysmorphic ears and cardiopathy. Standard and molecular cytogenetics showed a complex rearrangement characterised by a pericentromeric inversion in one of chromosomes 12 and an inverted insertional translocation of the 12q14q21.1 region, from the rearranged chromosome 12, into the q21q22.1 tract of a chromosome 16. Array-CGH analysis unravelled a partial 16q21q22.1 monosomy, localised in the rearranged chromosome 16. CONCLUSIONS The comparison of the present case to other 16q21q22 monosomies contributed to narrow down the critical region for cardiac anomalies in the 16q22 deletion syndrome. However, more cases, well characterised both for phenotypic signs and genomic details, are needed to further restrict candidate regions for phenotypic signs in 16q deletions. The present case also provided evidence that a very complex rearrangement, possibly caused by a chromothripsis event, might be hidden behind a classical phenotype that is specific for a syndrome.
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Affiliation(s)
- Rita Genesio
- DMMBM, Universita' di Napoli Federico II, Naples, Italy
| | | | | | | | | | | | - Anna Conti
- DMMBM, Universita' di Napoli Federico II, Naples, Italy
| | | | - Lucio Nitsch
- DMMBM, Universita' di Napoli Federico II, Naples, Italy
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7
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Recurrent reciprocal 1q21.1 deletions and duplications associated with microcephaly or macrocephaly and developmental and behavioral abnormalities. Nat Genet 2008; 40:1466-71. [PMID: 19029900 DOI: 10.1038/ng.279] [Citation(s) in RCA: 426] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Accepted: 10/15/2008] [Indexed: 01/29/2023]
Abstract
Chromosome region 1q21.1 contains extensive and complex low-copy repeats, and copy number variants (CNVs) in this region have recently been reported in association with congenital heart defects, developmental delay, schizophrenia and related psychoses. We describe 21 probands with the 1q21.1 microdeletion and 15 probands with the 1q21.1 microduplication. These CNVs were inherited in most of the cases in which parental studies were available. Consistent and statistically significant features of microcephaly and macrocephaly were found in individuals with microdeletion and microduplication, respectively. Notably, a paralog of the HYDIN gene located on 16q22.2 and implicated in autosomal recessive hydrocephalus was inserted into the 1q21.1 region during the evolution of Homo sapiens; we found this locus to be deleted or duplicated in the individuals we studied, making it a probable candidate for the head size abnormalities observed. We propose that recurrent reciprocal microdeletions and microduplications within 1q21.1 represent previously unknown genomic disorders characterized by abnormal head size along with a spectrum of developmental delay, neuropsychiatric abnormalities, dysmorphic features and congenital anomalies. These phenotypes are subject to incomplete penetrance and variable expressivity.
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8
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Yamamoto T, Dowa Y, Ueda H, Kawataki M, Asou T, Sasaki Y, Harada N, Matsumoto N, Matsuoka R, Kurosawa K. Tetralogy of Fallot associated with pulmonary atresia and major aortopulmonary collateral arteries in a patient with interstitial deletion of 16q21-q22.1. Am J Med Genet A 2008; 146A:1575-80. [PMID: 18470894 DOI: 10.1002/ajmg.a.32204] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A newborn male had an interstitial deletion of 16q21-q22.1 accompanying tetralogy of Fallot associated with pulmonary atresia and major aortopulmonary collateral arteries (MAPCA), dysmorphic craniofacial features, failure to thrive, and severe psychomotor developmental delay. When the deletion in this patient and other reported patients are compared, the 16q22 region appears to be the smallest region for 16q deletion syndrome. Since over 50% of patients with the deletion of 16q22 region have congenital heart disease, there may be a responsible gene in this region.
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Affiliation(s)
- Toshiyuki Yamamoto
- International Research and Educational Institute for Integrated Medical Sciences, Tokyo Women's Medical University, Tokyo, Japan.
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Khan A, Hyde RK, Dutra A, Mohide P, Liu P. Core binding factor beta (CBFB) haploinsufficiency due to an interstitial deletion at 16q21q22 resulting in delayed cranial ossification, cleft palate, congenital heart anomalies, and feeding difficulties but favorable outcome. Am J Med Genet A 2007; 140:2349-54. [PMID: 17022082 DOI: 10.1002/ajmg.a.31479] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The core binding factor beta gene (CBFB), essential to bone morphogenesis, is located at 16q22.1. Homozygous deficiency of CBFB leads to ossification defects in mice. CBFB forms a heterodimer with RUNX2 (CBFA1) during embryonic bone development. RUNX2 mutations lead to cleidocranial dysplasia in humans. We describe an infant boy with an interstitial deletion of 16q21q22, delayed skull ossification, cleft palate, and heart anomalies who had a difficult course in infancy but eventually improved and is healthy. He was found to have CBFB haploinsufficiency, but did not have mutations in RUNX2. We suggest that 16q21q22 deletion be considered when there are antenatal or postnatal findings of enlarged cranial sutures with or without cleft palate. The finding of CBFB haploinsufficiency in our case and the similarity of cranial ossification defects with a mouse model of CBFB deletion suggest a role for CBFB in cranial bone development in humans.
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Affiliation(s)
- Aneal Khan
- Department of Pediatrics, McMaster Children's Hospital, McMaster University, Hamilton, Ontario, Canada.
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10
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Goto T, Aramaki M, Yoshihashi H, Nishimura G, Hasegawa Y, Takahashi T, Ishii T, Fukushima Y, Kosaki K. Large fontanelles are a shared feature of haploinsufficiency of RUNX2 and its co-activator CBFB. Congenit Anom (Kyoto) 2004; 44:225-9. [PMID: 15566413 DOI: 10.1111/j.1741-4520.2004.00043.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
CBFB at 16q22 heterodimerizes with either RUNX2 (also known as CBFA1) or RUNX1 (CBFA2) to activate the transcription of downstream molecules. RUNX2 regulates osteoblast differentiation and chondrocyte maturation and its haploinsufficiency leads to cleidocranial dysplasia, characterized large fontanelles, hypoplasia or aplasia of the clavicles, hypoplasia of the distal phalanges, and a wide pubic symphysis. Complete loss of Runx1 or Cbfb in mice is lethal because of the absence of fetal liver hematopoiesis. Fetal rescue in Cbfb(-/-) mice by providing the Cbfb functions in the hematopoietic progenitors leads to wide fontanelle and delayed chondrocyte maturation, presumably resulting from the incomplete function of the transcriptional pathway mediated by the Cbfb-Runx2 heterodimer. The present report describes a patient with a small deletion of chromosome 16q22.1 encompassing CBFB. Skeletal abnormalities included a widely open fontanelle, multiple wormian bones along the sagittal suture, hypoplasia of the distal phalanges, and mildly shortened clavicles. G-banding analysis revealed a shortening of the 16q22.1 band. A fluorescence in situ hybridization analysis, using the BAC probe spanning the CBFB locus at 16q22.1, revealed that the CBFB probe hybridized to only one of the two homologous chromosome 16 regions. Array-comparative genomic hybridization analysis revealed that the deletion spans 1.2 megabases. In reviewing eight previously reported cases of 16q interstitial deletions involving band q22, large cranial sutures were noted in all but one case. Considering the phenotypic similarity of the 16q22 deletion case and Cbfb(-/-) mice rescued for hematopoiesis and the consistency of the phenotype among 16q22 deletion cases, we suggest that the common phenotypic feature of the 16q22 deletion, large fontanelles, can be attributed to a haploinsufficiency of CBFB.
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Affiliation(s)
- Tomohide Goto
- Department of Neurology, Tokyo Metropolitan Kiyose Children's Hospital, Tokyo, Japan
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11
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McKenzie F, Turner A, Withers S, Dalzell P, McGlynn M, Kirk EPE. Dominant inheritance of cleft palate, microstomia and micrognathia--possible linkage to the fragile site at 16q22 (FRA16B). Clin Dysmorphol 2002; 11:237-41. [PMID: 12401987 DOI: 10.1097/00019605-200210000-00002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We report a family in which a father and his three children are affected with microstomia, micrognathia and partial or complete cleft of the hard and soft palate. The probands were non-identical twins, a boy and a girl, both noted to have the above features soon after birth. Their father was diagnosed with a submucous cleft of the palate at the age of 4 years and their older brother has milder facial features and a bifid uvula. All affected family members were demonstrated to have a fragile site on chromosome 16q22 but otherwise normal karyotypes. Of interest is a previously described family with autosomal dominant inheritance of U-shaped cleft palate, microstomia, micrognathia and oligodontia where all affected members were shown to have the fragile site at 16q22 in a proportion of their cells [Bettex et al. (1998) Eur J Pediatr Surg 8:4-8]. We propose that these two conditions are the same and represent a distinctive syndrome involving aberrant orofacial development that may be linked to the fragile site at 16q22.
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Affiliation(s)
- F McKenzie
- Hunter Genetics & University of Newcastle, Newcastle, NSW, Australia
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12
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He W, Tuck-Muller CM, Martínez JE, Li S, Rowley ER, Wertelecki W. Molecular characterization of a ring chromosome 16 from a patient with bilateral cataracts. AMERICAN JOURNAL OF MEDICAL GENETICS 2002; 107:12-7. [PMID: 11807861 DOI: 10.1002/ajmg.10091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A four-month-old white female, who was referred to us for genetic evaluation because of severe developmental delay, dysmorphic features, and bilateral cataracts, was found by routine cytogenetic analysis to have ring chromosome 16 in almost all cells analyzed. Ring chromosome 16 was confirmed and further delineated by fluorescence in situ hybridization (FISH). Breakpoints between loci D16S521 and KG8 on the short arm and D16S3121 and D16S303 on the long arm of chromosome 16 were determined by polymerase chain reaction (PCR) analysis. The deleted chromosome was of maternal origin. To our knowledge, this is the first case of ring chromosome 16 associated with bilateral cataracts. Comparison of previously reported cases with deletion of chromosome 16 and our case suggests the presence of cataract locus within 1 Mb of the terminus of 16q.
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Affiliation(s)
- Weigong He
- Department of Medical Genetics, University of South Alabama, Mobile, Alabama, USA
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13
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Chen CP, Chern SR, Lee CC, Chen LF, Chuang CY. Prenatal diagnosis ofde novo interstitial 16q deletion in a fetus associated with sonographic findings of prominent coronal sutures, a prominent frontal bone, and shortening of the long bones. Prenat Diagn 1998. [DOI: 10.1002/(sici)1097-0223(199805)18:5<490::aid-pd281>3.0.co;2-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Monaghan KG, Van Dyke DL, Wiktor A, Feldman GL. Cytogenetic and clinical findings in a patient with a deletion of 16q23.1: first report of bilateral cataracts and a 16q deletion. AMERICAN JOURNAL OF MEDICAL GENETICS 1997; 73:180-3. [PMID: 9409869 DOI: 10.1002/(sici)1096-8628(1997)73:2<180::aid-ajmg13>3.0.co;2-q] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The most commonly reported manifestations of 16q deletions are severe growth and developmental disorders and anomalies of the craniofacial, visceral, and musculoskeletal systems. We reviewed the findings of patients reported with 16q- syndrome and compared them to our patient, a 4 1/2-year-old boy with a deletion of 16q23.1. Findings include psychomotor retardation, hypotonia, high forehead, hypertelorism, upslanting palpebral fissures, low-set abnormally modeled ears, and talipes equinovarus. Anomalies present in our patient not reported in others with 16q- syndrome include bilateral cataracts, iris coloboma, and autistic-like behavior. It is of note that a locus for autosomal dominant congenital cataract, known as Marner cataract, was mapped previously to 16q22. Because our patient has bilateral cataracts and a unilateral iris coloboma, it seems likely that a gene involved in ocular development is located within 16q23.1. Our patient's deletion may also include the gene involved in Marner cataract and may further assist in the isolation of this gene.
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Affiliation(s)
- K G Monaghan
- Department of Medical Genetics, Henry Ford Hospital, Detroit, Michigan 48202, USA
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15
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Werner W, Kraft S, Callen DF, Bartsch O, Hinkel GK. A small deletion of 16q23.1→16q24.2 [del(16)(q23.1q24.2).ish del(16)(q23.1q24.2)(D16S395+, D16S348−, P5432+)] in a boy with iris coloboma and minor anomalies. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/(sici)1096-8628(19970627)70:4<371::aid-ajmg8>3.0.co;2-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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16
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Callen DF, Eyre H, Lane S, Shen Y, Hansmann I, Spinner N, Zackai E, McDonald-McGinn D, Schuffenhauer S, Wauters J. High resolution mapping of interstitial long arm deletions of chromosome 16: relationship to phenotype. J Med Genet 1993; 30:828-32. [PMID: 8230159 PMCID: PMC1016564 DOI: 10.1136/jmg.30.10.828] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The breakpoints of seven interstitial deletions of the long arm of chromosome 16 and two ring chromosomes of this chromosome were mapped by in situ hybridisation or by analysis of mouse/human somatic cell hybrids containing the deleted chromosome 16. Use of a high resolution cytogenetic based physical map of chromosome 16 enabled breakpoints to be assigned to an average resolution of at least 1.6 Mb. In general, interstitial deletions involving q12 or q22.1 have broadly similar phenotypes though there are differences in specific abnormalities. Deletions involving regions more distal, from 16q22.1 to 16q24.1, were associated with relatively mild dysmorphism. One region of the long arm, q24.2 to q24.3, was not involved in any deletion, either in this study or in any previous report. Presumably, monosomy for this region is lethal. In contrast, patients with deletions of 16q21 have a normal phenotype. These results are consistent with the proposed distribution of genes, frequent in telomeric Giesma light band regions but infrequent in G positive bands.
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Affiliation(s)
- D F Callen
- Department of Cytogenetics and Molecular Genetics, Women's and Children's Hospital, North Adelaide, Australia
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17
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Abstract
The recently published, detailed cytogenetic-based physical map of chromosome 16 has the highest resolution of any autosomal cytogenetic map thus far constructed. The genetic map has been integrated with the cytogenetic map to facilitate the regional localization of disease genes by linkage. Disease genes for tuberous sclerosis, familial Mediterranean fever, Rubinstein-Taybi syndrome and Morquio A syndrome have now been assigned to chromosome 16. The search for the adult polycystic kidney disease gene has recently been narrowed to the analysis of candidate loci on chromosome 16, and localization of the gene determining juvenile Batten disease has been further refined by disequilibrium mapping.
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Affiliation(s)
- J C Mulley
- Department of Cytogenetics and Molecular Genetics, Women's and Children's Hospital, North Adelaide, Australia
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18
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Trautmann U, Pfeiffer RA, Seufert-Satomi U, Tietze HU. Simultaneous de novo interstitial deletion of 16q21 and intercalary duplication of 19q in a retarded infant with minor dysmorphic features. J Med Genet 1993; 30:330-1. [PMID: 8487285 PMCID: PMC1016348 DOI: 10.1136/jmg.30.4.330] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We report on a retarded infant with minor dysmorphic features in whom deletion 16 and duplication 19q were discovered. The karyotype is 46,XX,del(16) (q13.08-21.05),dup(19)(q13.13-13.2). The origin and significance of the aberrant chromosomes are unknown.
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Affiliation(s)
- U Trautmann
- Institut für Humangenetik, Friedrich-Alexander Universität Erlangen-Nürnberg, Germany
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