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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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Vij R, Batra P, Vij H. Cleidocranial dysplasia: complete clinical, radiological and histological profiles. BMJ Case Rep 2013; 2013:bcr-2013-009015. [PMID: 23519515 DOI: 10.1136/bcr-2013-009015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Cleidocranial dysplasia is an autosomal-dominant condition characterised by widely patent calvarial sutures, clavicular hypoplasia, supernumerary teeth and short stature. Though it is not a very uncommon occurrence, its histopathological features are not frequently reported. This paper presents a similar case with complete clinical, radiological, histological and treatment profiles.
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Affiliation(s)
- Ruchieka Vij
- Department of Oral Pathology & Microbiology, Institute of Dental Studies and Technologies, Modinagar, Uttar Pradesh, India
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Northup JK, Matalon R, Lockhart LH, Hawkins JC, Velagaleti GVN. A complex chromosome rearrangement, der(6)ins(6)(p21.1q25.3q27)inv(6)(p25.3q27), in a child with cleidocranial dysplasia. Eur J Med Genet 2011; 54:e394-8. [PMID: 21466863 DOI: 10.1016/j.ejmg.2011.03.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Accepted: 03/25/2011] [Indexed: 10/18/2022]
Abstract
Complex chromosome rearrangements (CCRs) are structural abnormalities involving >2 chromosomes or >3 breakpoints. It has been suggested that the probability of imbalance increases as the number of breakpoints increase. Here we report a 7-month-old, Hispanic girl presenting with cleidocranial dysplasia (CCD) who was found to have a complex chromosome rearrangement of chromosome 6. Fluorescence in situ hybridization studies with bacterial artificial chromosome (BAC) clones showed that the rearrangement involved insertion of 6q into 6p disrupting the "Runt related transcription factor 2 (RUNX2)" gene at chromosome 6p21.1. In addition, a pericentric inversion of chromosome 6 was identified. Despite the complex nature of the rearrangement, no cryptic deletions or duplications could be detected by array comparative genomic hybridization.
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Affiliation(s)
- Jill K Northup
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 78229, USA
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Purandare SM, Mendoza-Londono R, Yatsenko SA, Napierala D, Scott DA, Sibai T, Casas K, Wilson P, Lee J, Muneer R, Leonard JC, Ramji FG, Lachman R, Li S, Stankiewicz P, Lee B, Mulvihill JJ. De novo three-way chromosome translocation 46,XY,t(4;6;21)(p16;p21.1;q21) in a male with cleidocranial dysplasia. Am J Med Genet A 2008; 146A:453-8. [PMID: 18203189 PMCID: PMC2663417 DOI: 10.1002/ajmg.a.31750] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cleidocranial dysplasia (CCD) is an autosomal dominant skeletal dysplasia associated with cranial, clavicular, and dental anomalies. It is caused by mutations in the RUNX2 gene, which encodes an osteoblast-specific transcription factor and maps to chromosome 6p21. We report clinical and molecular cytogenetic studies in a patient with clinical features of CCD including wormian bones, delayed fontanel closure, hypoplastic clavicles and pubic rami, and supernumerary dentition. Additional abnormalities of bone growth and connective tissue, including easy bruisability, scarring, bleeding, joint hypermobility, and developmental delay were also observed. Molecular cytogenetic studies identified a de novo apparently balanced three-way translocation 46,XY,t(4;6;21)(p16;p21.1;q21). Further mapping revealed the breakpoint on 6p21 to be ∼50 kb upstream of exon 1 of the RUNX2 gene, with RUNX2 being intact on the derivative chromosome 6. We hypothesize that the proband's CCD has arisen from disruption of the developmentally regulated gene RUNX2 at the 6p21 breakpoint, due to a position effect mutation which may have altered the expression of the gene. Further studies might unravel a new regulatory element for RUNX2.
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Affiliation(s)
- Smita M Purandare
- Section of Genetics, Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
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Otto F, Kanegane H, Mundlos S. Mutations in the RUNX2 gene in patients with cleidocranial dysplasia. Hum Mutat 2002; 19:209-16. [PMID: 11857736 DOI: 10.1002/humu.10043] [Citation(s) in RCA: 202] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Cleidocranial dysplasia (CCD) is a autosomal dominant disorder characterized by skeletal anomalies such as patent fontanels, late closure of cranial sutures with Wormian bones, late erupting secondary dentition, rudimentary clavicles, and short stature. The locus for this disease was mapped to chromosome 6p21. RUNX2 is a member of the runt family of transcription factors and its expression is restricted to developing osteoblasts and a subset of chondrocytes. Mutations in the RUNX2 gene have been shown to cause CCD. Chromosomal translocations, deletions, insertions, nonsense and splice-site mutations, as well as missense mutations of the RUNX2 gene have been described in CCD patients. Although there is a wide spectrum in phenotypic variability ranging from primary dental anomalies to all CCD features plus osteoporosis, no clear phenotype-genotype correlation has been established. However analysis of the three-dimensional structure of the DNA binding runt domain of the RUNX proteins and its interaction with DNA, as well as the cofactor CBFB, start to provide an insight into how missense mutations affect RUNX2 function.
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Affiliation(s)
- Florian Otto
- Department of Hematology/Oncology, University of Freiburg Medical Center, Freiburg, Germany.
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Ponzio GM, Cunningham ML. Clavicular hypoplasia, zygomatic arch hypoplasia, and micrognathia: a newly defined syndrome. AMERICAN JOURNAL OF MEDICAL GENETICS 2000; 92:200-5. [PMID: 10817655 DOI: 10.1002/(sici)1096-8628(20000529)92:3<200::aid-ajmg8>3.0.co;2-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We report on a 6-year-old boy with a previously undefined syndrome of clavicular hypoplasia, frontonasal malformation, zygomatic arch hypoplasia, micrognathia, and normal intelligence. His condition differs from similar syndromes on the basis of unique facial findings such as microcornea, stellate irises, and a midline maxillary cleft. We present his case, a review of the literature, and propose the acronym CHZAM, for clavicular hypoplasia, zygomatic arch, and micrognathia, to represent this syndrome.
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Affiliation(s)
- G M Ponzio
- University of Vermont College of Medicine, Burlington, USA
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