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Güneş N, Uludağ Alkaya D, Toylu A, Özüdoğru P, Çifçi Sunamak E, Şeker A, Demir B, Kuruğoğlu S, Mıhçı E, Tüysüz B. Phenotypic and Molecular Spectrum of a Turkish Cohort with Hereditary Multiple Osteochondromas. Turk Arch Pediatr 2023; 58:376-381. [PMID: 37317574 PMCID: PMC10440955 DOI: 10.5152/turkarchpediatr.2023.23011] [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: 01/13/2023] [Accepted: 03/28/2023] [Indexed: 06/16/2023]
Abstract
OBJECTIVE Hereditary multiple osteochondromas is an autosomal dominant disorder caused by heterozygous pathogenic variants in EXT1 or EXT2. We aimed to evaluate the clinical and molecular findings of a Turkish cohort with hereditary multiple osteochondroma. MATERIALS AND METHODS Thirty-two patients aged 1.3-49.6 years from 22 families were enrolled. Genetic analyses were made by EXT1 and/or EXT2 sequencing and chromosomal microarray analyses. RESULTS We found 17 intragenic pathogenic variants in EXT1 (13/17) and EXT2 (4/17), 12 of which are novel. Four probands had EXT1 deletions, including 2 patients with partial EXT1 microdeletions involving exons 2-11 and 5-11, and 2 patients with whole-gene deletions. In 21 variants, the frequency of truncating and missense variants was 76.1% and 23.8%, respectively. Two families had no detectable variants in EXT1 and EXT2. All patients had multiple osteochondromas at the long bones, mainly at the tibia, forearm, femur, and humerus. Bowing deformity of the forearms (9/32) and the lower extremities (2/32), and scoliosis (6/32) were observed. The clinical severity was not different between patients with EXT1 or EXT2 variants. One patient with an EXT2 variant and another with an EXT1 microdeletion had the most severe phenotype with class III disease. Four patients with no EXT1 or EXT2 variants had milder phenotypes. Intrafamilial variability in disease severity was not observed. CONCLUSION We report a hereditary multiple osteochondroma cohort with clinical and molecular data including 12 novel intragenic variants in EXT1 or EXT2, and 4 microdeletions involving EXT1. Taken together, our data expand the existing knowledge of the phenotype-genotype spectrum in hereditary multiple osteochondroma.
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Affiliation(s)
- Nilay Güneş
- Department of Pediatric Genetics, İstanbul University-Cerrahpaşa, Cerrahpaşa Faculty of Medicine, İstanbul, Turkey
| | - Dilek Uludağ Alkaya
- Department of Pediatric Genetics, İstanbul University-Cerrahpaşa, Cerrahpaşa Faculty of Medicine, İstanbul, Turkey
| | - Aslı Toylu
- Department of Medical Genetics, Akdeniz University Faculty of Medicine, Antalya, Turkey
| | - Püren Özüdoğru
- Department of Pediatric Genetics, Akdeniz University Faculty of Medicine, Antalya, Turkey
| | - Evrim Çifçi Sunamak
- Department of Pediatric Genetics, İstanbul University-Cerrahpaşa, Cerrahpaşa Faculty of Medicine, İstanbul, Turkey
| | - Ali Şeker
- Department of Orthopedics and Traumatology, İstanbul University-Cerrahpaşa, Cerrahpaşa Faculty of Medicine, Istanbul, Turkey
| | - Bilal Demir
- Department of Orthopedics and Traumatology, Metin Sabancı Baltalimanı Bone Diseases Training and Research Center, Health Sciences University, İstanbul, Turkey
| | - Sebuh Kuruğoğlu
- Department of Radiology, İstanbul University-Cerrahpaşa, Cerrahpaşa Faculty of Medicine, İstanbul, Turkey
| | - Ercan Mıhçı
- Department of Pediatric Genetics, Akdeniz University Faculty of Medicine, Antalya, Turkey
| | - Beyhan Tüysüz
- Department of Pediatric Genetics, İstanbul University-Cerrahpaşa, Cerrahpaşa Faculty of Medicine, İstanbul, Turkey
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Yang H, Wang L. Heparan sulfate proteoglycans in cancer: Pathogenesis and therapeutic potential. Adv Cancer Res 2023; 157:251-291. [PMID: 36725112 DOI: 10.1016/bs.acr.2022.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The heparan sulfate proteoglycans (HSPGs) are glycoproteins that consist of a proteoglycan "core" protein and covalently attached heparan sulfate (HS) chain. HSPGs are ubiquitously expressed in mammalian cells on the cell surface and in the extracellular matrix (ECM) and secretory vesicles. Within HSPGs, the protein cores determine when and where HSPG expression takes place, and the HS chains mediate most of HSPG's biological roles through binding various protein ligands, including cytokines, chemokines, growth factors and receptors, morphogens, proteases, protease inhibitors, and ECM proteins. Through these interactions, HSPGs modulate cell proliferation, adhesion, migration, invasion, and angiogenesis to display essential functions in physiology and pathology. Under physiological conditions, the expression and localization of HSPGs are finely regulated to orchestrate their physiological functions, and this is disrupted in cancer. The HSPG dysregulation elicits multiple oncogenic signaling, including growth factor signaling, ECM and Integrin signaling, chemokine and immune signaling, cancer stem cell, cell differentiation, apoptosis, and senescence, to prompt cell transformation, proliferation, tumor invasion and metastasis, tumor angiogenesis and inflammation, and immunotolerance. These oncogenic roles make HSPGs an attractive pharmacological target for anti-cancer therapy. Several therapeutic strategies have been under development, including anti-HSPG antibodies, peptides and HS mimetics, synthetic xylosides, and heparinase inhibitors, and shown promising anti-cancer efficacy. Therefore, much progress has been made in this line of study. However, it needs to bear in mind that the roles of HSPGs in cancer can be either oncogenic or tumor-suppressive, depending on the HSPG and the cancer cell type with the underlying mechanisms that remain obscure. Further studies need to address these to fill the knowledge gap and rationalize more efficient therapeutic targeting.
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Affiliation(s)
- Hua Yang
- Department of Molecular Pharmacology & Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Lianchun Wang
- Department of Molecular Pharmacology & Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States; Bryd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, United States.
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Mundy C, Chung J, Koyama E, Bunting S, Mahimkar R, Pacifici M. Osteochondroma formation is independent of heparanase expression as revealed in a mouse model of hereditary multiple exostoses. J Orthop Res 2022; 40:2391-2401. [PMID: 34996123 PMCID: PMC9259764 DOI: 10.1002/jor.25260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 12/20/2021] [Accepted: 01/05/2022] [Indexed: 02/04/2023]
Abstract
Hereditary multiple exostoses (HME) is a rare, pediatric disorder characterized by osteochondromas that form along growth plates and provoke significant musculoskeletal problems. HME is caused by mutations in heparan sulfate (HS)-synthesizing enzymes EXT1 or EXT2. Seemingly paradoxically, osteochondromas were found to contain excessive extracellular heparanase (Hpse) that could further reduce HS levels and exacerbate pathogenesis. To test Hpse roles, we asked whether its ablation would protect against osteochondroma formation in a conditional HME model consisting of mice bearing floxed Ext1 alleles in Agr-CreER background (Ext1f/f ;Agr-CreER mice). Mice were crossed with a new global Hpse-null (Hpse-/- ) mice to produce compound Hpse-/- ;Ext1f/f ;Agr-CreER mice. Tamoxifen injection of standard juvenile Ext1f/f ;Agr-CreER mice elicited stochastic Ext1 ablation in growth plate and perichondrium, followed by osteochondroma formation, as revealed by microcomputed tomography and histochemistry. When we examined companion conditional Ext1-deficient mice lacking Hpse also, we detected no major decreases in osteochondroma number, skeletal distribution, and overall structure by the analytical criteria above. The Ext1 mutants used here closely mimic human HME pathogenesis, but have not been previously tested for responsiveness to treatments. To exclude some innate therapeutic resistance in this stochastic model, tamoxifen-injected Ext1f/f ;Agr-CreER mice were administered daily doses of the retinoid Palovarotene, previously shown to prevent ectopic cartilage and bone formation in other mouse disease models. This treatment did inhibit osteochondroma formation compared with vehicle-treated mice. Our data indicate that heparanase is not a major factor in osteochondroma initiation and accumulation in mice. Possible roles of heparanase upregulation in disease severity in patients are discussed.
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Affiliation(s)
- Christina Mundy
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Juliet Chung
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Eiki Koyama
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | | | | | - Maurizio Pacifici
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
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Matsumoto K, Ogawa H, Komura S, Akiyama H. Functional Impairment of Hip Joint and Activities of Daily Living Failure in Patients with Multiple Hereditary Exostoses. Indian J Orthop 2022; 56:1572-1577. [PMID: 36052379 PMCID: PMC9385922 DOI: 10.1007/s43465-022-00681-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 06/06/2022] [Indexed: 02/04/2023]
Abstract
OBJECTIVE In this study, we focused on the hip joints and examined pain and functional impairment, and their relationship with anatomical characteristics in MHE patients. METHODS Patients with MHE followed up in our hospital from January 2020 to December 2020 were enrolled. Clinical hip functional outcomes were evaluated using the Japanese Orthopedic Association (JOA) hip score and hip range of motion (ROM). Proximal femur geometric measurements were evaluated using radiography. RESULTS A total of 39 patients (78 hips) with a median age of 25.6 years and average JOA score of 94.0 ± 10.5 were included. Eight patients felt pain in their hip joints. The average ROM score was 18.2 ± 2.5, and 47.4% of the patients with MHE had ROM limitation. The average score of ability to walk was 19.6 ± 1.8, and three patients had some problems with walking. The average ADL score was 18.2 ± 2.5, and 51.3% of patients with MHE had some failures in ADL. The hip flexion and internal rotation were markedly restricted compared with the normal values. When patients were grouped according to their ADL scores, we found that the ADL failure group had a significantly lower ROM score than the no ADL failure group (p < 0.0001), and there were significant differences between the groups in terms of femoral neck widening (p = 0.0001). CONCLUSIONS We found that half of MHE patients had some failures in their ADL due to hip functional impairment. The study results also suggest that femoral neck widening affected ADL failure and ROM limitation.
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Affiliation(s)
- Kazu Matsumoto
- Department of Orthopaedic Surgery, Graduate School of Medicine, Gifu University, 1-1, Yanagido, Gifu, 501-1194 Japan
- Orthopedic Surgery, Gifu Seiryu Hospital, Gifu, Japan
| | - Hiroyasu Ogawa
- Department of Orthopaedic Surgery, Graduate School of Medicine, Gifu University, 1-1, Yanagido, Gifu, 501-1194 Japan
- Department of Orthopaedic Surgery, Ogaki Tokushukai Hospital, Gifu, Japan
| | - Shingo Komura
- Department of Orthopaedic Surgery, Graduate School of Medicine, Gifu University, 1-1, Yanagido, Gifu, 501-1194 Japan
| | - Haruhiko Akiyama
- Department of Orthopaedic Surgery, Graduate School of Medicine, Gifu University, 1-1, Yanagido, Gifu, 501-1194 Japan
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Wilson LFL, Dendooven T, Hardwick SW, Echevarría-Poza A, Tryfona T, Krogh KBRM, Chirgadze DY, Luisi BF, Logan DT, Mani K, Dupree P. The structure of EXTL3 helps to explain the different roles of bi-domain exostosins in heparan sulfate synthesis. Nat Commun 2022; 13:3314. [PMID: 35676258 PMCID: PMC9178029 DOI: 10.1038/s41467-022-31048-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 05/31/2022] [Indexed: 11/08/2022] Open
Abstract
Heparan sulfate is a highly modified O-linked glycan that performs diverse physiological roles in animal tissues. Though quickly modified, it is initially synthesised as a polysaccharide of alternating β-D-glucuronosyl and N-acetyl-α-D-glucosaminyl residues by exostosins. These enzymes generally possess two glycosyltransferase domains (GT47 and GT64)-each thought to add one type of monosaccharide unit to the backbone. Although previous structures of murine exostosin-like 2 (EXTL2) provide insight into the GT64 domain, the rest of the bi-domain architecture is yet to be characterised; hence, how the two domains co-operate is unknown. Here, we report the structure of human exostosin-like 3 (EXTL3) in apo and UDP-bound forms. We explain the ineffectiveness of EXTL3's GT47 domain to transfer β-D-glucuronosyl units, and we observe that, in general, the bi-domain architecture would preclude a processive mechanism of backbone extension. We therefore propose that heparan sulfate backbone polymerisation occurs by a simple dissociative mechanism.
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Affiliation(s)
- L F L Wilson
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, 22903, USA
| | - T Dendooven
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - S W Hardwick
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK
| | - A Echevarría-Poza
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | - T Tryfona
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | - K B R M Krogh
- Department of Protein Biochemistry and Stability, Novozymes A/S, Krogshøjvej 36, 2880, Bagsværd, Denmark
| | - D Y Chirgadze
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK
| | - B F Luisi
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK
| | - D T Logan
- Biochemistry and Structural Biology, Centre for Molecular Protein Science, Department of Chemistry, Lund University, SE-221 00, Lund, Sweden
| | - K Mani
- Department of Experimental Medical Science, Division of Neuroscience, Glycobiology Group, Lund University, SE-221 00, Lund, Sweden.
| | - P Dupree
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK.
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Wang W, Yang M, Shen Y, Chen K, Wu D, Yang C, Bai J, He D, Gao J. Clinical survey of a pedigree with hereditary multiple exostoses and identification of EXT‑2 gene deletion mutation. Mol Med Rep 2022; 25:141. [PMID: 35211766 PMCID: PMC8915398 DOI: 10.3892/mmr.2022.12657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 02/10/2022] [Indexed: 11/06/2022] Open
Abstract
The aim of the present study was to report a clinical survey of hereditary multiple exostoses (HME) in a large Chinese pedigree, and the identification of a novel deletion mutation of exostosin glycosyltransferase 2 (EXT‑2) gene. A patient with multiple exostoses with huge cartilage‑capped tumors in scapula, knees and ankles received surgery in Department of Orthopedics (Shanghai Changhai Hospital). A total of 20 family members were recruited to the study, with seven members (five male; two female) diagnosed as HME. The family members of the patients with HME were examined, clinical data and peripheral blood samples were collected, and their DNA was sequenced. The incidence of HME in this family pedigree was 35%. Exostoses were most frequently in the tibiae with occurrence in six patients, followed by ribs, femurs, radii, fibulae, scapulae and humeri. DNA sequencing of peripheral blood revealed a novel deletion mutation, c.824‑826delGCA, in exon 5 of the EXT‑2 gene, which was observed in all the patients with HME, but not in the healthy family members. Several characteristics of HME in the pedigree were observed, such as susceptibility of male gender, decreased average age of onset and height and increased severity of clinical symptoms with generations.
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Affiliation(s)
- Wentao Wang
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai 200433, P.R. China
| | - Mingyuan Yang
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai 200433, P.R. China
| | - Yuhang Shen
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai 200433, P.R. China
| | - Kai Chen
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai 200433, P.R. China
| | - Donghua Wu
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai 200433, P.R. China
| | - Changwei Yang
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai 200433, P.R. China
| | - Jinyi Bai
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai 200433, P.R. China
| | - Dawei He
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai 200433, P.R. China
| | - Jun Gao
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai 200433, P.R. China
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Li J, Wang Z, Han Y, Jin C, Cheng D, Zhou YA, Zhen J. Genetic and functional analyses detect an EXT1 splicing pathogenic variant in a Chinese hereditary multiple exostosis (HME) family. Mol Genet Genomic Med 2022; 10:e1878. [PMID: 35106951 PMCID: PMC8922959 DOI: 10.1002/mgg3.1878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 12/19/2021] [Accepted: 01/06/2022] [Indexed: 11/22/2022] Open
Abstract
Background Hereditary multiple exostosis (HME) is an autosomal dominant skeletal disorder characterized by the development of multiple cartilage‐covered tumors on the external surfaces of bones (osteochondromas). Most of HME cases result from heterozygous loss‐of‐function mutations in EXT1 or EXT2 gene. Methods Clinical examination was performed to diagnose the patients: Whole exome sequencing (WES) was used to identify pathogenic mutations in the proband, which is confirmed by Sanger sequencing and co‐segregation analysis: qRT‐PCR was performed to identify the mRNA expression level of EXT1 in patient peripheral blood samples: minigene splicing assay was performed to mimic the splicing process of EXT1 variants in vitro. Results We evaluated the pathogenicity of EXT1 c.1056 + 1G > T in a Chinese family with HME. The clinical, phenotypic, and genetic characterization of patients in this family were described. The variant was detected by whole‐exome sequencing (WES) and confirmed by Sanger sequencing. Sequencing of the RT‐PCR products from the patient's blood sample identified a large deletion (94 nucleotides), which is the whole exome 2 of the EXT1 cDNA. Splicing assay indicated that the mutated minigene produced alternatively spliced transcripts, which cause a frameshift resulting in an early termination of protein expression. Conclusions Our study establishes the pathogenesis of the splicing mutation EXT1 c.1056 + 1G > T to HME and provides scientific foundation for accurate diagnosis and precise medical intervention for HME.
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Affiliation(s)
- Jianwei Li
- The Second Hospital, Shanxi Medical University, Taiyuan, China
| | - Zhiqiang Wang
- Lvliang People's Hospital, Shanxi Medical University, Lvliang, China
| | - Yaxin Han
- The First Hospital, Shanxi Medical University, Taiyuan, China
| | - Chengfang Jin
- Lvliang People's Hospital, Shanxi Medical University, Lvliang, China
| | - Dalin Cheng
- Lvliang People's Hospital, Shanxi Medical University, Lvliang, China
| | - Yong-An Zhou
- The Second Hospital, Shanxi Medical University, Taiyuan, China
| | - Junping Zhen
- The Second Hospital, Shanxi Medical University, Taiyuan, China
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Bukowska-Olech E, Trzebiatowska W, Czech W, Drzymała O, Frąk P, Klarowski F, Kłusek P, Szwajkowska A, Jamsheer A. Hereditary Multiple Exostoses-A Review of the Molecular Background, Diagnostics, and Potential Therapeutic Strategies. Front Genet 2021; 12:759129. [PMID: 34956317 PMCID: PMC8704583 DOI: 10.3389/fgene.2021.759129] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 11/08/2021] [Indexed: 11/17/2022] Open
Abstract
Hereditary multiple exostoses (HMEs) syndrome, also known as multiple osteochondromas, represents a rare and severe human skeletal disorder. The disease is characterized by multiple benign cartilage-capped bony outgrowths, termed exostoses or osteochondromas, that locate most commonly in the juxta-epiphyseal portions of long bones. Affected individuals usually complain of persistent pain caused by the pressure on neighboring tissues, disturbance of blood circulation, or rarely by spinal cord compression. However, the most severe complication of this condition is malignant transformation into chondrosarcoma, occurring in up to 3.9% of HMEs patients. The disease results mainly from heterozygous loss-of-function alterations in the EXT1 or EXT2 genes, encoding Golgi-associated glycosyltransferases, responsible for heparan sulfate biosynthesis. Some of the patients with HMEs do not carry pathogenic variants in those genes, hence the presence of somatic mutations, deep intronic variants, or another genes/loci is suggested. This review presents the systematic analysis of current cellular and molecular concepts of HMEs along with clinical characteristics, clinical and molecular diagnostic methods, differential diagnosis, and potential treatment options.
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Affiliation(s)
| | | | - Wiktor Czech
- Medical Student, Poznan University of Medical Sciences, Poznan, Poland
| | - Olga Drzymała
- Medical Student, Poznan University of Medical Sciences, Poznan, Poland
| | - Piotr Frąk
- Medical Student, Poznan University of Medical Sciences, Poznan, Poland
| | | | - Piotr Kłusek
- Medical Student, Poznan University of Medical Sciences, Poznan, Poland
| | - Anna Szwajkowska
- Medical Student, Poznan University of Medical Sciences, Poznan, Poland
| | - Aleksander Jamsheer
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland.,Centers for Medical Genetics GENESIS, Poznan, Poland
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Komura S, Matsumoto K, Hirakawa A, Akiyama H. Natural History and Characteristics of Hand Exostoses in Multiple Hereditary Exostoses. J Hand Surg Am 2021; 46:815.e1-815.e12. [PMID: 33642092 DOI: 10.1016/j.jhsa.2020.12.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 10/05/2020] [Accepted: 12/16/2020] [Indexed: 02/02/2023]
Abstract
PURPOSE Multiple hereditary exostoses (MHEs) comprise a rare skeletal disorder. This study aimed to elucidate the natural history and characteristics of hand exostoses by focusing on their progression or regression and their association with shortening and angular deformation of the finger bones. METHODS Of 60 MHE patients who presented to our hospital between 2005 and 2019, 32 patients (62 hands) who underwent hand x-ray examinations were included in a study of initial presentation. Among them, 15 patients (30 hands) who underwent consecutive x-ray examinations before epiphyseal closure were included in a subsequent follow-up study (follow-up period, 6.9 years). We investigated the incidence and common location of hand involvement by exostoses during the initial examination study. We further investigated the progression or regression of hand exostoses and the influence of hand exostoses on longitudinal bone growth and the angular deformation of finger bones during the follow-up study. RESULTS In the initial study, we observed exostoses in 30 (60 hands) of 32 (62 hands) patients. The average number of exostoses per hand was 5.2. Exostoses developed more frequently in the middle and ring proximal phalanges and the fifth metacarpal. In the follow-up study, 3.1 exostoses per hand spontaneously regressed and 2.9 exostoses per hand occurred de novo with growth. Progression of exostoses was mainly observed by approximately age 15 years; thereafter, spontaneous regression became dominant. Regression of exostoses was frequently observed in metacarpals, whereas de novo exostoses frequently occurred in phalangeal bones, particularly in distal phalanges. Growth plate involvement by exostoses did not influence the longitudinal growth of finger bones, but it increased their angulation. CONCLUSIONS The hand is a common location of exostoses development for MHE patients. Although some exostoses in the hands regress with skeletal maturity, hand involvement by exostoses can result in angular deformity. TYPE OF STUDY/LEVEL OF EVIDENCE Diagnostic IV.
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Affiliation(s)
- Shingo Komura
- Department of Orthopaedic Surgery, Gifu University Graduate School of Medicine, Gifu, Japan.
| | - Kazu Matsumoto
- Department of Orthopaedic Surgery, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Akihiro Hirakawa
- Department of Orthopaedic Surgery, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Haruhiko Akiyama
- Department of Orthopaedic Surgery, Gifu University Graduate School of Medicine, Gifu, Japan
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Mutational Analysis of EXT1in a Chinese Family Affected by Hereditary Multiple Osteochondroma. BIOMED RESEARCH INTERNATIONAL 2021; 2021:8888948. [PMID: 34409107 PMCID: PMC8367584 DOI: 10.1155/2021/8888948] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 07/08/2021] [Indexed: 11/17/2022]
Abstract
Objectives To discuss the mutational features and their relationships with disease in a family with hereditary multiple osteochondroma (HMO) from Guangxi Province (GXBB-1 family), China. Methods Genomic DNA and total mRNA were extracted from peripheral blood cells of GXBB-1 family members. Whole elements of the EXT1gene and its transcript, including exons, introns, exon-intron boundaries, and coding sequence (CDS) clones, were amplified and sequenced. Allele-specific PCR was used to confirm the position and type of mutation. Results All patients from the GXBB-1 family harbored the cosegregating heterozygous c.1056+1G>A mutation located in EXT1at an exon-intron boundary. Another three single-nucleotide polymorphisms (SNPs) were also detected in the patients, including IVS2+1G>A in intron 2, c.1844 T>C [p.Pro (CCT) 614Pro (CCC)] in exon 3, and c.2534G>A [p.Glu (GAG) 844Glu (GAA)] in exon 9. The latter two SNPs were synonymous variations. Conclusions The heterozygous c.1056+1G>A mutation cosegregated with the phenotype, indicating that it is a pathogenic mutation in the GXBB-1 family. This mutation is reported for the first time in Chinese HMO patients. IVS2+1G>A and c.2534G>A have no relationship with the occurrence of disease. However, c.1844 T>C and c.1056+1G>A are linked, and their interaction needs to be further studied. c.1844T>C is a new SNP that has not been reported internationally.
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Guo X, Chen S, Lin M, Pan Y, Liu N, Shi T. A Novel Intronic Splicing Mutation in the EXT2 Gene of a Chinese Family with Multiple Osteochondroma. Genet Test Mol Biomarkers 2021; 25:478-485. [PMID: 34280007 DOI: 10.1089/gtmb.2021.0030] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Background: Multiple osteochondroma (MO), an autosomal dominant genetic disease, is caused by heterozygous mutations in the EXT1 and EXT2 genes. Approximately 80% of pathogenic mutations are nonsense/missense mutations, small indels, and splicing mutations. Splicing mutations, particularly at the 3' and 5' splice sites, disrupt normal mRNA processing and cause exon skipping or aberrant splicing, ultimately resulting in protein truncation and loss of function. Methods: Polymerase chain reaction (PCR) and Sanger sequencing were applied to detect subtle mutations in a Chinese family with MO, the pathogenicity of a splicing variant was predicted by bioinformatics and further verified using a minigene splicing assay. Results: A novel and heterozygous splicing mutation, c.626 + 2_626 + 5delTAGG, was identified in the EXT2 gene of the proband and the father by PCR and Sanger sequencing, whereas the unaffected mother and brother had wild-type alleles at the same site. Bioinformatics predicted that the 5' splicing site of exon 3 in the EXT2 gene was destroyed due to this mutation. A hybrid minigene splicing assay (HMSA) indicated that the mutation disturbed the normal splicing of the EXT2 gene mRNA and led to a deletion of 79 bp at the 5' end of exon 3, which resulted in aberrant splicing of exon 3 and introduced an earlier stop codon in the EXT2 gene. Conclusion: A novel splicing mutation was identified that produced the MO phenotype through aberrant splicing in a Chinese family. This observation, expands our knowledge of the spectrum of molecular pathogenic mechanisms leading to aberrant mRNA splicing.
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Affiliation(s)
- Xiaoyan Guo
- Department of Laboratory Medicine, Fuzhou Second Hospital Affiliated to Xiamen University, Fuzhou, P.R. China
| | - Shunyou Chen
- Department of Orthopedics, and Fuzhou Second Hospital Affiliated to Xiamen University, Fuzhou, P.R. China
| | - Mingrui Lin
- Intensive Care Unit, The Affiliated People's Hospital of Fujian Traditional Medical University, Fuzhou, P.R. China
| | - Yuancheng Pan
- Department of Orthopedics, and Fuzhou Second Hospital Affiliated to Xiamen University, Fuzhou, P.R. China
| | - Nannan Liu
- Department of Orthopedics Institute, Fuzhou Second Hospital Affiliated to Xiamen University, Fuzhou, P.R. China
| | - Tengfei Shi
- Department of Laboratory Medicine, Fuzhou Second Hospital Affiliated to Xiamen University, Fuzhou, P.R. China
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Matsumoto K, Ishimaru D, Ogawa H, Komura S, Shimizu K, Akiyama H. Correlation between mutated genes and forearm deformity in patients with multiple osteochondroma. J Orthop Sci 2021; 26:483-486. [PMID: 32636136 DOI: 10.1016/j.jos.2020.05.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 04/15/2020] [Accepted: 05/07/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUNDS Exostosin-1 (EXT1) and exostosin-2 (EXT2) cause multiple osteochondromas (MO). In this study, we investigated the correlation between forearm deformity and mutant EXTs in Japanese families with MO. METHODS We evaluated 112 patients in 71 families with MO. Genomic DNA was isolated from peripheral blood leucocytes. Of these, 28 patients were selected and underwent radiography for their forearms since they had gross forearm deformities. We measured the radial articular angle (RAA), ulna variance (UV), carpal slip (CS), and percentage of radial bowing (%RB) to compare between patients with mutant EXT1 or EXT2 and those with missense or other mutations using Student's t-test. RESULTS Twenty-two (78.6%) and 6 (11.4%) out of 28 patients had mutations in EXT1 and EXT2, respectively. Nine (32.1%) and 19 (67.9%) of the 28 patients had missense and other mutations, respectively. The mean age of patients with EXT1 and EXT2 were 25.9 ± 20.3 and 33.5 ± 25.4 years, respectively and those with missense mutation and other mutations were 28.7 ± 27.0 and 24.6 ± 17.0 years, respectively. There were no significant differences in RAA, UV, and RB between patients harbouring mutant EXT1 or EXT2 (RAA, 40.1 ± 8.7 and 31.5 ± 13.9°; UV, -2.7 ± 5.7 and -3.1 ± 3.7 mm; %RB, 8.6 ± 1.5 and 8.3 ± 2.0%). CS was significantly greater in patients with mutant EXT1 than that in those with mutant EXT2 (EXT1, 44.1 ± 16.8%; EXT2, 18.6 ± 14.0%). There were no significant differences in RAA, UV, CS and %RB between patients with missense and other mutations. CONCLUSIONS Patients with mutant EXT1 displayed greater CS than patients with mutant EXT2, indicating that patients with MO harbouring EXT1 mutations sustain more severe ulnar drift deformities than those with EXT2 mutations.
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Affiliation(s)
- Kazu Matsumoto
- Department of Orthopaedic Surgery, Gifu University, Graduate School of Medicine, Gifu, Japan.
| | - Daichi Ishimaru
- Department of Orthopaedic Surgery, Gifu University, Graduate School of Medicine, Gifu, Japan; Department of Orthopaedic Surgery, Gujo Municipal Hospital, Gifu, Japan
| | - Hiroyasu Ogawa
- Department of Orthopaedic Surgery, Gifu University, Graduate School of Medicine, Gifu, Japan
| | - Shingo Komura
- Department of Orthopaedic Surgery, Gifu University, Graduate School of Medicine, Gifu, Japan
| | - Katsuji Shimizu
- Department of Orthopaedic Surgery, Gifu University, Graduate School of Medicine, Gifu, Japan; Department of Orthopaedic Surgery, Gifu Municipal Hospital, Japan
| | - Haruhiko Akiyama
- Department of Orthopaedic Surgery, Gifu University, Graduate School of Medicine, Gifu, Japan
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Al-Zayed Z, Al-Rijjal RA, Al-Ghofaili L, BinEssa HA, Pant R, Alrabiah A, Al-Hussainan T, Zou M, Meyer BF, Shi Y. Mutation spectrum of EXT1 and EXT2 in the Saudi patients with hereditary multiple exostoses. Orphanet J Rare Dis 2021; 16:100. [PMID: 33632255 PMCID: PMC7905910 DOI: 10.1186/s13023-021-01738-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 02/11/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Hereditary Multiple Exostoses (HME), also known as Multiple Osteochondromas (MO) is a rare genetic disorder characterized by multiple benign cartilaginous bone tumors, which are caused by mutations in the genes for exostosin glycosyltransferase 1 (EXT1) and exostosin glycosyltransferase 2 (EXT2). The genetic defects have not been studied in the Saudi patients. AIM OF STUDY We investigated mutation spectrum of EXT1 and EXT2 in 22 patients from 17 unrelated families. METHODS Genomic DNA was extracted from peripheral leucocytes. The coding regions and intron-exon boundaries of both EXT1 and EXT2 genes were screened for mutations by PCR-sequencing analysis. Gross deletions were analyzed by MLPA analysis. RESULTS EXT1 mutations were detected in 6 families (35%) and 3 were novel mutations: c.739G > T (p. E247*), c.1319delG (p.R440Lfs*4), and c.1786delA (p.S596Afs*25). EXT2 mutations were detected in 7 families (41%) and 3 were novel mutations: c.541delG (p.D181Ifs*89), c.583delG (p.G195Vfs*75), and a gross deletion of approximately 10 kb including promoter and exon 1. Five patients from different families had no family history and carried de novo mutations (29%, 5/17). No EXT1 and EXT2 mutations were found in the remaining four families. In total, EXT1 and EXT2 mutations were found in 77% (13/17) of Saudi HME patients. CONCLUSION EXT1 and EXT2 mutations contribute significantly to the pathogenesis of HME in the Saudi population. In contrast to high mutation rate in EXT 1 (65%) and low mutation rate in EXT2 (25%) in other populations, the frequency of EXT2 mutations are much higher (41%) and comparable to that of EXT1 among Saudi patients. De novo mutations are also common and the six novel EXT1/EXT2 mutations further expands the mutation spectrum of HME.
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Affiliation(s)
- Zayed Al-Zayed
- Department of Orthopedics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Roua A Al-Rijjal
- Department of Genetics, MBC 3, Centre for Genomic Medicine, King Faisal Specialist Hospital and Research Center, P.O. Box 3354, Riyadh, 11211, Saudi Arabia
| | | | - Huda A BinEssa
- Department of Genetics, MBC 3, Centre for Genomic Medicine, King Faisal Specialist Hospital and Research Center, P.O. Box 3354, Riyadh, 11211, Saudi Arabia
| | - Rajeev Pant
- Department of Orthopedics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Anwar Alrabiah
- Department of Orthopedics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Thamer Al-Hussainan
- Department of Orthopedics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Minjing Zou
- Department of Genetics, MBC 3, Centre for Genomic Medicine, King Faisal Specialist Hospital and Research Center, P.O. Box 3354, Riyadh, 11211, Saudi Arabia
| | - Brian F Meyer
- Department of Genetics, MBC 3, Centre for Genomic Medicine, King Faisal Specialist Hospital and Research Center, P.O. Box 3354, Riyadh, 11211, Saudi Arabia
| | - Yufei Shi
- Department of Genetics, MBC 3, Centre for Genomic Medicine, King Faisal Specialist Hospital and Research Center, P.O. Box 3354, Riyadh, 11211, Saudi Arabia.
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Kong W, Chen Y, Zhao Z, Zhang L, Lin X, Luo X, Wang S, Song Z, Lin X, Lai G, Yu Z. EXT1 methylation promotes proliferation and migration and predicts the clinical outcome of non-small cell lung carcinoma via WNT signalling pathway. J Cell Mol Med 2021; 25:2609-2620. [PMID: 33565239 PMCID: PMC7933929 DOI: 10.1111/jcmm.16277] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 12/29/2020] [Accepted: 12/31/2020] [Indexed: 01/15/2023] Open
Abstract
DNA methylation is important for lung cancer prognosis. In this work, it is aimed to seek novel biomarkers with DNA methylation‐expression‐pathway pattern and explore its underlying mechanism. Prognostic DNA methylation sites and mRNAs were screened in NSCLC data set from TCGA, and further validated using the samples retrospectively collected, and EXT1 was identified as a potential target. Gene body methylation of three CpG sites (cg03276982, cg11592677, cg16286281) on EXT1 was significantly associated with clinical outcome, and the EXT1 gene expression also predicted prognosis. The expression level of EXT1 was also correlated with its DNA methylation level. This observation was further validated in a new data set consist of 170 samples. Knocking down of EXT1 resulted in decreased proliferation and migration. EXT1 targets were analysed using GSEA. It is found that the WNT signalling is the potential downstream target of EXT1. Further analyses revealed that the EXT1 targets the beta‐catenin and effect migration rate of NSCLC cell lines. The WNT signalling inhibitor, XAV‐939, effectively disrupted the migration promotion effect induced by EXT1. In summary, EXT1 methylation regulates the gene expression, effects the proliferation and migration via WNT pathway and predicted a poor prognosis for NSCLC.
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Affiliation(s)
- Wencui Kong
- Department of Respiratory Medicine and Critical Care Medicine, The 900th Hospital of Joint Logistic Support Force, PLA, Fuzhou, China
| | - Ying Chen
- Department of Respiratory Medicine and Critical Care Medicine, The 900th Hospital of Joint Logistic Support Force, PLA, Fuzhou, China
| | - Zhongquan Zhao
- Department of Respiratory Medicine and Critical Care Medicine, The 900th Hospital of Joint Logistic Support Force, PLA, Fuzhou, China
| | - Lei Zhang
- Department of Respiratory Medicine and Critical Care Medicine, The 900th Hospital of Joint Logistic Support Force, PLA, Fuzhou, China
| | - Xiandong Lin
- Laboratory of Radiation Oncology and Radiobiology, Fujian Cancer Hospital and Fujian Medical University Cancer Hospital, Fuzhou, China
| | - Xingguang Luo
- Division of Human Genetics, Department of Psychiatry, Yale University School of Medicine, West Haven, CT, USA
| | - Shuiliang Wang
- Department of Urology, 900th Hospital of the Joint Logistics Team Support Force, Fujian Medical University, Fuzhou, China.,Fujian Key Laboratory of Transplant Biology, Affiliated Dongfang Hospital, Xiamen University School of Medicine, Fuzhou, China
| | - Zhengbo Song
- Institute of Cancer and Basic Medicine, Chinese Academy of Sciences, Hangzhou, China.,Department of Medical Oncology, Cancer Hospital of the University of Chinese Academy of Sciences, Hangzhou, China.,Department of Medical Oncology, Zhejiang Cancer Hospital, Hangzhou, China
| | - Xiangwu Lin
- Medical Oncology, The 900th Hospital of Joint Logistic Support Force, PLA, Fuzhou, China
| | - Guoxiang Lai
- Department of Respiratory Medicine and Critical Care Medicine, The 900th Hospital of Joint Logistic Support Force, PLA, Fuzhou, China
| | - Zongyang Yu
- Department of Respiratory Medicine and Critical Care Medicine, The 900th Hospital of Joint Logistic Support Force, PLA, Fujian Medical University,Affiliated Dongfang Hospital, Xiamen University School of Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, China
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Wang Y, Zhong L, Xu Y, Ding L, Ji Y, Schutz S, Férec C, Cooper DN, Xu C, Chen JM, Luo Y. EXT1 and EXT2 Variants in 22 Chinese Families With Multiple Osteochondromas: Seven New Variants and Potentiation of Preimplantation Genetic Testing and Prenatal Diagnosis. Front Genet 2020; 11:607838. [PMID: 33414810 PMCID: PMC7783290 DOI: 10.3389/fgene.2020.607838] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 12/02/2020] [Indexed: 11/13/2022] Open
Abstract
Multiple osteochondromas (MO), the most common type of benign bone tumor, is an autosomal dominant skeletal disorder characterized by multiple cartilage-capped bony protuberances. In most cases, EXT1 and EXT2, which encode glycosyltransferases involved in the biosynthesis of heparan sulfate, are the genes responsible. Here we describe the clinical, phenotypic and genetic characterization of MO in 22 unrelated Chinese families involving a total of 60 patients. Variant detection was performed by means of a battery of different techniques including Sanger sequencing and whole-exome sequencing (WES). The pathogenicity of the missense and splicing variants was explored by means of in silico prediction algorithms. Sixteen unique pathogenic variants, including 10 in the EXT1 gene and 6 in the EXT2 gene, were identified in 18 (82%) of the 22 families. Fourteen (88%) of the 16 variants were predicted to give rise to truncated proteins whereas the remaining two were missense. Seven variants were newly described here, further expanding the spectrum of MO-causing variants in the EXT1 and EXT2 genes. More importantly, the identification of causative variants allowed us to provide genetic counseling to 8 MO patients in terms either of preimplantation genetic testing (PGT) or prenatal diagnosis, thereby preventing the reoccurrence of MO in the corresponding families. This study is the first to report the successful implementation of PGT in MO families and describes the largest number of subjects undergoing prenatal diagnosis to date.
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Affiliation(s)
- Ye Wang
- Fetal Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Liangying Zhong
- Department of Laboratory Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yan Xu
- Reproductive Medicine Center, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Reproductive Medicine, Guangzhou, China
| | - Lei Ding
- Department of Radiology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yuanjun Ji
- Fetal Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Sacha Schutz
- Inserm, Univ Brest, EFS, UMR 1078, GGB, Brest, France
- CHRU Brest, Brest, France
| | - Claude Férec
- Inserm, Univ Brest, EFS, UMR 1078, GGB, Brest, France
- CHRU Brest, Brest, France
| | - David N. Cooper
- School of Medicine, Institute of Medical Genetics, Cardiff University, Cardiff, United Kingdom
| | - Caixia Xu
- Research Center for Translational Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Jian-Min Chen
- Inserm, Univ Brest, EFS, UMR 1078, GGB, Brest, France
| | - Yanmin Luo
- Fetal Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
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Matsumoto K, Ogawa H, Nozawa S, Akiyama H. An analysis of osteoporosis in patients with hereditary multiple exostoses. Osteoporos Int 2020; 31:2355-2361. [PMID: 32642853 DOI: 10.1007/s00198-020-05533-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 07/01/2020] [Indexed: 11/30/2022]
Abstract
UNLABELLED We analyzed osteoporosis in 20 HME patients. According to the T-score of BMD, 30% and 67.5% of the patients fell in the range of osteopenia in the lumbar spine and femoral neck. Our results indicate HME patients have low bone mass. They do not have abnormal bone metabolism. INTRODUCTION There are few reports of osteoporosis in hereditary multiple exostoses (HME) patients. Therefore, the purpose of this study was to analyze osteoporosis in HME patients. METHODS This retrospective cohort study included 20 patients diagnosed with HME. Patients underwent bone mineral density (BMD) measurement of the lumbar spine (n = 20) and femoral neck (n = 40). Bone metabolic parameters, including serum osteocalcin and urinary cross-linked N-telopeptide of type 1 collagen (NTx), were analyzed in all subjects. EXT1 and EXT2 genes were sequenced using genomic DNA. We also examined the correlation between genotype and BMD Z-score and T-score. RESULTS The mean BMD values of the lumbar spine were 1.085 ± 0.116 g/cm2 (n = 11) in male and 1.108 ± 0.088 g/cm2 (n = 9) in female. The mean BMD values of the femoral neck area were 0.759 ± 0.125 g/cm2 (n = 22) in male and 0.749 ± 0.115 g/cm2 (n = 18) in female. Z-score of most HME patients show < 0, indicating that these patients tend to have low bone mass compared with the age-matched population. According to the T-score of BMD, 30% (6 of 20) and 67.5% (27 of 40) of the patients fell in the range of osteopenia in the lumbar spine and femoral neck areas, respectively. Serum osteocalcin and urinary NTx were in the normal range in most patients. There was no significant correlation between genotypes and Z-score. CONCLUSION HME patients have low bone mass, especially in the femoral neck area. They do not have abnormal bone metabolism, and there was no correlation between genotypes and Z-score.
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Affiliation(s)
- K Matsumoto
- Department of Orthopaedic Surgery, Gifu University, Graduate School of Medicine, 1-1, Yanagido, Gifu, 501-1194, Japan.
| | - H Ogawa
- Department of Orthopaedic Surgery, Gifu University, Graduate School of Medicine, 1-1, Yanagido, Gifu, 501-1194, Japan
| | - S Nozawa
- Department of Orthopaedic Surgery, Gifu University, Graduate School of Medicine, 1-1, Yanagido, Gifu, 501-1194, Japan
| | - H Akiyama
- Department of Orthopaedic Surgery, Gifu University, Graduate School of Medicine, 1-1, Yanagido, Gifu, 501-1194, Japan
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Li Y, Lin X, Zhu M, Xun F, Li J, Yuan Z, Liu Y, Xu H. A mutation in SLC20A2 (c.C1849T) promotes proliferation while inhibiting hypertrophic differentiation in ATDC5 chondrocytes. Bone Joint Res 2020; 9:751-760. [PMID: 33135420 PMCID: PMC7649514 DOI: 10.1302/2046-3758.911.bjr-2020-0112.r1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Aims This study aimed to investigate the effect of solute carrier family 20 member 2 (SLC20A2) gene mutation (identified from a hereditary multiple exostoses family) on chondrocyte proliferation and differentiation. Methods ATDC5 chondrocytes were cultured in insulin-transferrin-selenium medium to induce differentiation. Cells were transfected with pcDNA3.0 plasmids with either a wild-type (WT) or mutated (MUT) SLC20A2 gene. The inorganic phosphate (Pi) concentration in the medium of cells was determined. The expression of markers of chondrocyte proliferation and differentiation, the Indian hedgehog (Ihh), and parathyroid hormone-related protein (PTHrP) pathway were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting. Results The expression of SLC20A2 in MUT group was similar to WT group. The Pi concentration in the medium of cells in MUT group was significantly higher than WT group, which meant the SLC20A2 mutation inhibited Pi uptake in ATDC5 chondrocytes. The proliferation rate of ATDC5 chondrocytes in MUT group was greater than WT group. The expression of aggrecan (Acan), α-1 chain of type II collagen (COL2A1), and SRY-box transcription factor 9 (SOX9) were higher in MUT group than WT group. However, the expression of Runt-related transcription factor 2 (Runx2), α-1 chain of type X collagen (COL10A1), and matrix metallopeptidase 13 (MMP13) was significantly decreased in the MUT group. Similar results were obtained by Alcian blue and Alizarin red staining. The expression of Ihh and PTHrP in MUT group was higher than WT group. An inhibitor (cyclopamine) of Ihh/PTHrP signalling pathway inhibited the proliferation and restored the differentiation of chondrocytes in MUT group. Conclusion A mutation in SLC20A2 (c.C1948T) decreases Pi uptake in ATDC5 chondrocytes. SLC20A2 mutation promotes chondrocyte proliferation while inhibiting chondrocyte differentiation. The Ihh/PTHrP signalling pathway may play an important role in this process. Cite this article: Bone Joint Res 2020;9(11):751–760.
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Affiliation(s)
- YiQiang Li
- Department of Pediatric Orthopaedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - XueMei Lin
- Department of Pediatric Orthopaedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - MingWei Zhu
- Department of Pediatric Orthopaedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - FuXing Xun
- Department of Pediatric Orthopaedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - JingChun Li
- Department of Pediatric Orthopaedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Zhe Yuan
- Department of Pediatric Orthopaedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - YanHan Liu
- Department of Pediatric Orthopaedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - HongWen Xu
- Department of Pediatric Orthopaedics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
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Matsumoto K, Ogawa H, Akiyama H. Radiographic characteristics of the hip joint in skeletally mature patients with multiple hereditary exostoses. Skeletal Radiol 2020; 49:1773-1779. [PMID: 32474654 DOI: 10.1007/s00256-020-03482-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/13/2020] [Accepted: 05/21/2020] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To elucidate the radiological characteristics of the hips, especially in proximal femur, of skeletally mature patients with multiple hereditary exostoses (MHE). MATERIALS AND METHODS Fifty eligible patients (100 hips) were included in the study and assigned to the MHE group. The control group included age- and sex-matched individuals, and the radiographs of 100 hips were used as controls. We examined the anatomical characteristics of the acetabulum and the proximal femur, including the acetabular depth-width ratio (ADR), Sharp's angle, femoral neck-shaft angle (NSA), Wiberg's centre-edge angle (CEA), femoral neck axis length (FNAL), femoral head diameter, (FHD), femoral neck width (FNW), femoral shaft width (FSW), femoral neck-shaft angle (NSA), and femoral head-neck ratio (FHNR = FHD/FNW). p value < 0.05 was considered significant. RESULTS Osteochondroma was frequently observed in the medial femoral neck (79%), but it was rarely found in the femoral head (1%). ADR and Sharp's angle were not significantly different between the MHE and control groups (p = 0.2056, p = 0.5025). CEA was significantly different between the two groups (p < 0.0001). FNW was significantly larger in the MHE group than in the control group (p < 0.0001). FHNR was significantly different between the two groups (p < 0.0001). NSA was significantly larger than the MHE group (141.8° ± 9.7° vs 129.5° ± 5.6°, p < 0.0001). CONCLUSIONS Hip dysplasia in the pelvic side was not commonly observed in skeletally mature MHE patients. However, they showed femoral neck widening and coxa valga. The occurrence of osteochondroma around the femoral neck affects the degree of valgus deformity. These facts could be useful for orthopaedic surgeons treating MHE patients.
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Affiliation(s)
- Kazu Matsumoto
- Department of Orthopaedic Surgery, Graduate School of Medicine, Gifu University, 1-1, Yanagido, Gifu, 501-1194, Japan.
| | - Hiroyasu Ogawa
- Department of Orthopaedic Surgery, Graduate School of Medicine, Gifu University, 1-1, Yanagido, Gifu, 501-1194, Japan
| | - Haruhiko Akiyama
- Department of Orthopaedic Surgery, Graduate School of Medicine, Gifu University, 1-1, Yanagido, Gifu, 501-1194, Japan
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Kawashima K, Ogawa H, Komura S, Ishihara T, Yamaguchi Y, Akiyama H, Matsumoto K. Heparan sulfate deficiency leads to hypertrophic chondrocytes by increasing bone morphogenetic protein signaling. Osteoarthritis Cartilage 2020; 28:1459-1470. [PMID: 32818603 PMCID: PMC7606622 DOI: 10.1016/j.joca.2020.08.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 08/03/2020] [Accepted: 08/11/2020] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Exostosin-1 (EXT1) and EXT2 are the major genetic etiologies of multiple hereditary exostoses and are essential for heparan sulfate (HS) biosynthesis. Previous studies investigating HS in several mouse models of multiple hereditary exostoses have reported that aberrant bone morphogenetic protein (BMP) signaling promotes osteochondroma formation in Ext1-deficient mice. This study examined the mechanism underlying the effects of HS deficiency on BMP/Smad signaling in articular cartilage in a cartilage-specific Ext-/- mouse model. METHOD We generated mice with a conditional Ext1 knockout in cartilage tissue (Ext1-cKO mice) using Prg4-Cre transgenic mice. Structural cartilage alterations were histologically evaluated and phospho-Smad1/5/9 (pSmad1/5/9) expression in mouse chondrocytes was analyzed. The effect of pharmacological intervention of BMP signaling using a specific inhibitor was assessed in the articular cartilage of Ext1-cKO mice. RESULTS Hypertrophic chondrocytes were significantly more abundant (P = 0.021) and cartilage thickness was greater in Ext1-cKO mice at 3 months postnatal than in control littermates (P = 0.036 for femur; and P < 0.001 for tibia). However, osteoarthritis did not spontaneously occur before the 1-year follow-up. matrix metalloproteinase (MMP)-13 and adamalysin-like metalloproteinases with thrombospondin motifs(ADAMTS)-5 were upregulated in hypertrophic chondrocytes of transgenic mice. Immunostaining and western blotting revealed that pSmad1/5/9-positive chondrocytes were more abundant in the articular cartilage of Ext1-cKO mice than in control littermates. Furthermore, the BMP inhibitor significantly decreased the number of hypertrophic chondrocytes in Ext1-cKO mice (P = 0.007). CONCLUSIONS HS deficiency in articular chondrocytes causes chondrocyte hypertrophy, wherein upregulated BMP/Smad signaling partially contributes to this phenotype. HS might play an important role in maintaining the cartilaginous matrix by regulating BMP signaling.
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Affiliation(s)
- K. Kawashima
- Department of Orthopaedic Surgery, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, Japan
| | - H. Ogawa
- Department of Orthopaedic Surgery, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, Japan
| | - S. Komura
- Department of Orthopaedic Surgery, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, Japan
| | - T. Ishihara
- Innovative and Clinical Research Promotion Center, Gifu University Hospital, 1-1 Yanagido, Gifu, Japan
| | - Y. Yamaguchi
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - H. Akiyama
- Department of Orthopaedic Surgery, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, Japan
| | - K. Matsumoto
- Department of Orthopaedic Surgery, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, Japan,Address correspondence and reprint requests to: K. Matsumoto, Department of Orthopedic Surgery, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, 501-1194, Japan. Tel.: 81-58-230-6333; Fax: 81-58-230-6334. (K. Matsumoto)
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20
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Li Y, Lin X, Zhu M, Li J, Yuan Z, Xu H. Whole‑exome sequencing identifies a novel mutation of SLC20A2 (c.C1849T) as a possible cause of hereditary multiple exostoses in a Chinese family. Mol Med Rep 2020; 22:2469-2477. [PMID: 32705272 PMCID: PMC7411400 DOI: 10.3892/mmr.2020.11298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 06/04/2020] [Indexed: 12/11/2022] Open
Abstract
Although the main causative genes for hereditary multiple exostoses (HME) are exostosin (EXT)‑1 and EXT‑2, there are numerous patients with HME without EXT‑1 and EXT‑2 mutations. The present study aimed to identify novel candidate genes for the development of HME in patients without EXT‑1 and EXT‑2 mutations. Whole‑exome sequencing was performed in a Chinese family with HME and without EXT‑1 and EXT‑2 mutations, followed by a combined bioinformatics pipeline including annotation and filtering processes to identify candidate variants. Candidate variants were then validated using Sanger sequencing. A total of 1,830 original variants were revealed to be heterozygous mutations in three patients with HME which were not present in healthy controls. Two mutations [c.C1849T in solute carrier family 20 member 2 (SLC20A2) and c.G506A in leucine zipper and EF‑hand containing transmembrane protein 1 (LETM1)] were identified as possible causative variants for HME through a bioinformatics filtering procedure and harmful prediction. Sanger sequencing results confirmed these two mutations in all patients with HME. A mutation in SLC20A2 (c.C1849T) led to a change in an amino acid (p.R617C), which may be involved in the development of HME by inducing metabolic disorders of phosphate and abnormal proliferation and differentiation in chondrocytes. In conclusion, the present study revealed two mutations [SLC20A2 (c.C1849T) and LETM1 (c.G506A) in a Chinese family with HME. The mutation in SLC20A2 (c.C1849T)] was more likely to be involved in the development of HME.
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Affiliation(s)
- Yiqiang Li
- Department of Pediatric Orthopedics, Guangzhou Women and Children's Medical Center, Guangzhou, Guangdong 510623, P.R. China
| | - Xuemei Lin
- Department of Pediatric Orthopedics, Guangzhou Women and Children's Medical Center, Guangzhou, Guangdong 510623, P.R. China
| | - Mingwei Zhu
- Department of Pediatric Orthopedics, Guangzhou Women and Children's Medical Center, Guangzhou, Guangdong 510623, P.R. China
| | - Jingchun Li
- Department of Pediatric Orthopedics, Guangzhou Women and Children's Medical Center, Guangzhou, Guangdong 510623, P.R. China
| | - Zhe Yuan
- Department of Pediatric Orthopedics, Guangzhou Women and Children's Medical Center, Guangzhou, Guangdong 510623, P.R. China
| | - Hongwen Xu
- Department of Pediatric Orthopedics, Guangzhou Women and Children's Medical Center, Guangzhou, Guangdong 510623, P.R. China
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21
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Fusco C, Nardella G, Fischetto R, Copetti M, Petracca A, Annunziata F, Augello B, D'Asdia MC, Petrucci S, Mattina T, Rella A, Cassina M, Bengala M, Biagini T, Causio FA, Caldarini C, Brancati F, De Luca A, Guarnieri V, Micale L, D'Agruma L, Castori M. Mutational spectrum and clinical signatures in 114 families with hereditary multiple osteochondromas: insights into molecular properties of selected exostosin variants. Hum Mol Genet 2020; 28:2133-2142. [PMID: 30806661 DOI: 10.1093/hmg/ddz046] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/22/2019] [Accepted: 02/22/2019] [Indexed: 01/05/2023] Open
Abstract
Hereditary multiple osteochondromas (HMO) is a rare autosomal dominant skeletal disorder, caused by heterozygous variants in either EXT1 or EXT2, which encode proteins involved in the biogenesis of heparan sulphate. Pathogenesis and genotype-phenotype correlations remain poorly understood. We studied 114 HMO families (158 affected individuals) with causative EXT1 or EXT2 variants identified by Sanger sequencing, or multiplex ligation-dependent probe amplification and qPCR. Eighty-seven disease-causative variants (55 novel and 32 known) were identified including frameshift (42%), nonsense (32%), missense (11%), splicing (10%) variants and genomic rearrangements (5%). Informative clinical features were available for 42 EXT1 and 27 EXT2 subjects. Osteochondromas were more frequent in EXT1 as compared to EXT2 patients. Anatomical distribution of lesions showed significant differences based on causative gene. Microscopy analysis for selected EXT1 and EXT2 variants verified that EXT1 and EXT2 mutants failed to co-localize each other and loss Golgi localization by surrounding the nucleus and/or assuming a diffuse intracellular distribution. In a cell viability study, cells expressing EXT1 and EXT2 mutants proliferated more slowly than cells expressing wild-type proteins. This confirms the physiological relevance of EXT1 and EXT2 Golgi co-localization and the key role of these proteins in the cell cycle. Taken together, our data expand genotype-phenotype correlations, offer further insights in the pathogenesis of HMO and open the path to future therapies.
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Affiliation(s)
- Carmela Fusco
- Division of Medical Genetics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Grazia Nardella
- Division of Medical Genetics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy.,Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Rita Fischetto
- Unit of Metabolic Diseases and Medical Genetics, University Hospital, P.O. Giovanni XXIII Hospital, Bari, Italy
| | - Massimiliano Copetti
- Unit of Biostatistics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Antonio Petracca
- Division of Medical Genetics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Francesca Annunziata
- Unit of Molecular Genetics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Bartolomeo Augello
- Division of Medical Genetics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Maria Cecilia D'Asdia
- Unit of Molecular Genetics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Simona Petrucci
- Unit of Molecular Genetics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy.,Department of Clinical and Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Teresa Mattina
- Unit of Medical Genetics, University of Catania, Catania, Italy
| | - Annalisa Rella
- Division of Medical Genetics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Matteo Cassina
- Unit of Clinical Genetics, Department of Women's and Children's Health, University of Padua, Padua, Italy
| | - Mario Bengala
- Dipartimento di Oncoematologia, U.O.C Laboratorio di Genetica Medica, Fondazione Policlinico di Tor Vergata, Rome, Italy
| | - Tommaso Biagini
- Unit of Bioinformatics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Francesco Andrea Causio
- Unit of Metabolic Diseases and Medical Genetics, University Hospital, P.O. Giovanni XXIII Hospital, Bari, Italy
| | - Camilla Caldarini
- Division of Orthopedics and Traumatology, Azienda Socio Sanitaria Territoriale Gaetano Pini, Milan, Italy
| | - Francesco Brancati
- Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy.,Laboratory of Molecular and Cell Biology, Istituto Dermopatico dell'Immacolata (IDI) IRCCS, Rome, Italy
| | - Alessandro De Luca
- Unit of Molecular Genetics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Vito Guarnieri
- Division of Medical Genetics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Lucia Micale
- Division of Medical Genetics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Leonardo D'Agruma
- Division of Medical Genetics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Marco Castori
- Division of Medical Genetics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
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22
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D'Arienzo A, Andreani L, Sacchetti F, Colangeli S, Capanna R. Hereditary Multiple Exostoses: Current Insights. Orthop Res Rev 2019; 11:199-211. [PMID: 31853203 PMCID: PMC6916679 DOI: 10.2147/orr.s183979] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 10/11/2019] [Indexed: 12/31/2022] Open
Abstract
Hereditary multiple exostoses (HME), also called hereditary multiple osteochondromas, is a rare genetic disorder characterized by multiple osteochondromas that grow near the growth plates of bones such as the ribs, pelvis, vertebrae and especially long bones. The disease presents with various clinical manifestations including chronic pain syndromes, restricted range of motion, limb deformity, short stature, scoliosis and neurovascular alteration. Malignant transformation of exostosis is rarely seen. The disease has no medical treatment and surgery is only recommended in symptomatic exostoses or in cases where a malignant transformation is suspected. HME is mainly caused by mutations and functional loss of the EXT1 and EXT2 genes which encode glycosyltransferases, an enzyme family involved in heparan sulfate (HS) synthesis. However, the peculiar molecular mechanism that leads to the structural changes of the cartilage and to osteochondroma formation is still being studied. Basic science studies have recently shown new insights about altering the molecular and cellular mechanism caused by HS deficiency. Pediatricians, geneticists and orthopedic surgeons play an important role in the study and treatment of this severe pathology. Despite the recent significant advances, we still need novel insights to better specify the role of HS in signal transduction. The purpose of this review was to analyze the most relevant aspects of HME from the literature review, give readers an important tool to understand its clinical features and metabolic-pathogenetic mechanism, and to identify an effective treatment method. We focused on the aspects of the disease related to clinical management and surgical treatment in order to give up-to-date information that could be useful for following best clinical practice.
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Affiliation(s)
- Antonio D'Arienzo
- Department of Translational Research on New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
| | - Lorenzo Andreani
- Department of Translational Research on New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
| | - Federico Sacchetti
- Department of Translational Research on New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
| | - Simone Colangeli
- Department of Translational Research on New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
| | - Rodolfo Capanna
- Department of Translational Research on New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
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23
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Yang A, Kim J, Jang JH, Lee C, Lee JE, Cho SY, Jin DK. Identification of a novel mutation in EXT2 in a fourth-generation Korean family with multiple osteochondromas and overview of mutation spectrum. Ann Hum Genet 2019; 83:160-170. [PMID: 30730578 DOI: 10.1111/ahg.12298] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 10/31/2018] [Accepted: 12/17/2018] [Indexed: 12/01/2022]
Abstract
Multiple osteochondromas (MOs) or hereditary multiple exostoses is a rare autosomal-dominant disease characterized by growths of MOs, which are benign cartilage-capped bone tumors that grow away from the growth plates. Almost 90% of MOs have a molecular explanation and 10% are unexplained. MOs are genetically heterogeneous with two causal genes on 8q24.11 (EXT1) and 11p12 (EXT2), with a higher frequency in EXT1. MO is a very rare genetic disorder, and the genotype-phenotype of MO with EXT2 mutation has not been well investigated in Korea. We present the clinical radiographic and molecular analysis of a four-generation Korean family with 11 MO-affected members (seven males and four females). The affected members from the third generation available for molecular analysis and their detailed medical histories showed moderate-to-severe phenotypes (clinical classes II-III), including bony deformities and limb misalignment with pain requiring surgical correction. The x-rays showed MOs in multiple sites. A novel EXT2 frameshift mutation (c.590delC, p.P197Qfs*73) was revealed by targeted exome sequencing in the affected members of this family. In this article, we not only expand the phenotypic-genotypic spectrum of MOs but also highlight the phenotypic heterogeneity in a family with the same mutation. In addition, we compiled the mutation spectrum of EXT2 from a literature review and identified that exon 2 of EXT2 is a mutation hot spot. Early medical attention with diagnosis of MO through careful examination of the clinical manifestations and genetic analysis can provide the opportunity to establish coordinated multispecialty management of the patient.
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Affiliation(s)
- Aram Yang
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Jinsup Kim
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Ja-Hyun Jang
- Green Cross Genome, Yongin-si, Republic of Korea
| | - Chung Lee
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Samsung Genome Institute, Samsung Medical Center, Seoul, Republic of Korea
| | - Ji-Eun Lee
- Department of Pediatrics, Inha University Hospital, Inha University Graduate School of Medicine, Incheon, Republic of Korea
| | - Sung Yoon Cho
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Dong-Kyu Jin
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
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24
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Mizumoto S. Defects in Biosynthesis of Glycosaminoglycans Cause Hereditary Bone, Skin, Heart, Immune, and Neurological Disorders. TRENDS GLYCOSCI GLYC 2018. [DOI: 10.4052/tigg.1812.2j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Shuji Mizumoto
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijo University
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25
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Santos SCL, Rizzo IMPO, Takata RI, Speck‐Martins CE, Brum JM, Sollaci C. Analysis of mutations in EXT1 and EXT2 in Brazilian patients with multiple osteochondromas. Mol Genet Genomic Med 2018. [PMID: 29529714 PMCID: PMC6014457 DOI: 10.1002/mgg3.382] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Background Multiple osteochondromas is a dysplasia characterized by growth of two or more osteochondromas. It is genetically heterogeneous, caused by pathogenic variants in EXT1 or EXT2 genes in 70%–90% of patients. The EXT1 is more often mutated than EXT2 gene, with a variable prevalence between populations. There are no data about EXT1 and EXT2 pathogenic variants in patients with multiple osteochondromas in Brazilian population. The aim of this survey is to characterize these to determine the genotype profile of this population. Methods DNA sequencing (Sanger Method) and MLPA analysis were performed to identify point mutations and deletions/duplications in the sample of 153 patients in 114 families. Results Germline variants were identified in 83% of families in which EXT2 variants were detected in 46% and EXT1 in 37% of cases. No variants were detected in 17% of them. We identified 50 different variants, 33 (13 frameshift, 11 nonsense, 5 missense, 2 splice site mutation, and 2 large deletions) in EXT1 and 17 (6 frameshift, 6 splice site mutation, 3 nonsense, 1 missense, and 1 large deletion) in EXT2. Of all 50 variants, 31 (62%) were novel, including 20 out of 33 (60,6%) EXT1 and 11 out of 17 (64.7%) EXT2 alleles. The vast majority of variants (88%) were “loss‐of‐function” and two novel hotspots in EXT2 gene were observed in our study. Conclusion The prevalence of variants detected in the EXT2 gene differs from other researches from Latin America, European, and Asian population. This uncommon prevalence could be related with the newly characterized variant hotspot sites detected in EXT2 gene (p.Ala409Profs*26 and p.Ser290*). A high number of novel variants were also identified indicating that Brazilian population has a unique genetic profile. Characterizing this population and establishing its genotype is essential to understand the molecular pathogenesis of this disease in Brazil.
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Affiliation(s)
- Savana C. L. Santos
- Molecular Pathology LaboratorySARAH Network of Rehabilitation HospitalsBrasíliaBrazil
| | | | - Reinaldo I. Takata
- Molecular Pathology LaboratorySARAH Network of Rehabilitation HospitalsBrasíliaBrazil
| | | | - Jaime M. Brum
- Department of Clinical GeneticsSARAH Network of Rehabilitation HospitalsBrasíliaBrazil
| | - Claudio Sollaci
- Department of OrthopaedicsSARAH Network of Rehabilitation HospitalsBrasíliaBrazil
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26
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Friedenberg SG, Vansteenkiste D, Yost O, Treeful AE, Meurs KM, Tokarz DA, Olby NJ. A de novo mutation in the EXT2 gene associated with osteochondromatosis in a litter of American Staffordshire Terriers. J Vet Intern Med 2018; 32:986-992. [PMID: 29485212 PMCID: PMC5980316 DOI: 10.1111/jvim.15073] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 01/02/2018] [Accepted: 01/18/2018] [Indexed: 12/30/2022] Open
Abstract
Background We aimed to identify mutations associated with osteochondromatosis in a litter of American Staffordshire Terrier puppies. Hypothesis We hypothesized that the associated mutation would be located in a gene that causes osteochondromatosis in humans. Animals A litter of 9 American Staffordshire puppies, their sire and dam, 3 of 4 grandparents, 26 healthy unrelated American Staffordshire Terriers, and 154 dogs of 27 different breeds. Methods Whole genome sequencing was performed on the proband, and variants were compared against polymorphisms derived from 154 additional dogs across 27 breeds, as well as single nucleotide polymorphism database 146. One variant was selected for follow‐up sequencing. Parentage and genetic mosaicism were evaluated across the litter. Results We found 56,301 genetic variants unique to the proband. Eleven variants were located in or near the gene exostosin 2 (EXT2), which is strongly associated with osteochondromatosis in humans. One heterozygous variant (c.969C > A) is predicted to result in a stop codon in exon 5 of the gene. Sanger sequencing identified the identical mutation in all affected offspring. The mutation was absent in the unaffected offspring, both parents, all available grandparents, and 26 healthy unrelated American Staffordshire Terriers. Conclusions and Clinical Importance These findings represent the first reported mutation associated with osteochondromatosis in dogs. Because this mutation arose de novo, the identical mutation is unlikely to be the cause of osteochondromatosis in other dogs. However, de novo mutations in EXT2 are common in humans with osteochondromatosis, and by extension, it is possible that dogs with osteochondromatosis could be identified by sequencing the entire EXT2 gene.
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Affiliation(s)
- Steven G Friedenberg
- Department of Veterinary Clinical Sciences, University of Minnesota, Saint Paul, Minnesota
| | | | - Oriana Yost
- Department of Clinical Sciences, North Carolina State University, Raleigh, North Carolina
| | - Amy E Treeful
- Department of Veterinary Clinical Sciences, University of Minnesota, Saint Paul, Minnesota
| | - Kathryn M Meurs
- Department of Clinical Sciences, North Carolina State University, Raleigh, North Carolina.,Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina
| | - Debra A Tokarz
- Department of Population Health and Pathobiology, North Carolina State University, Raleigh, North Carolina
| | - Natasha J Olby
- Department of Clinical Sciences, North Carolina State University, Raleigh, North Carolina.,Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina
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27
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Pacifici M. The pathogenic roles of heparan sulfate deficiency in hereditary multiple exostoses. Matrix Biol 2017; 71-72:28-39. [PMID: 29277722 DOI: 10.1016/j.matbio.2017.12.011] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/19/2017] [Accepted: 12/19/2017] [Indexed: 12/20/2022]
Abstract
Heparan sulfate (HS) is an essential component of cell surface and matrix proteoglycans (HS-PGs) that include syndecans and perlecan. Because of their unique structural features, the HS chains are able to specifically interact with signaling proteins -including bone morphogenetic proteins (BMPs)- via their HS-binding domain, regulating protein availability, distribution and action on target cells. Hereditary Multiple Exostoses (HME) is a rare pediatric disorder linked to germline heterozygous loss-of-function mutations in EXT1 or EXT2 that encode Golgi-resident glycosyltransferases responsible for HS synthesis, resulting in a systemic HS deficiency. HME is characterized by cartilaginous/bony tumors -called osteochondromas or exostoses- that form within perichondrium in long bones, ribs and other elements. This review examines most recent studies in HME, framing them in the context of classic studies. New findings show that the spectrum of EXT mutations is larger than previously realized and the clinical complications of HME extend beyond the skeleton. Osteochondroma development requires a somatic "second hit" that would complement the germline EXT mutation to further decrease HS production and/levels at perichondrial sites of osteochondroma induction. Cellular studies have shown that the steep decreases in local HS levels: derange the normal homeostatic signaling pathways keeping perichondrium mesenchymal; cause excessive BMP signaling; and provoke ectopic chondrogenesis and osteochondroma formation. Data from HME mouse models have revealed that systemic treatment with a BMP signaling antagonist markedly reduces osteochondroma formation. In sum, recent studies have provided major new insights into the molecular and cellular pathogenesis of HME and the roles played by HS deficiency. These new insights have led to the first ever proof-of-principle demonstration that osteochondroma formation is a druggable process, paving the way toward the creation of a clinically-relevant treatment.
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Affiliation(s)
- Maurizio Pacifici
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States.
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28
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Medek K, Zeman J, Honzík T, Hansíková H, Švecová Š, Beránková K, Kučerová Vidrová V, Kuklík M, Chomiak J, Tesařová M. Hereditary Multiple Exostoses: Clinical, Molecular and Radiologic Survey in 9 Families. Prague Med Rep 2017; 118:87-94. [PMID: 28922105 DOI: 10.14712/23362936.2017.8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Hereditary multiple exostoses (HME) represents a heterogeneous group of diseases often associated with progressive skeletal deformities. Most frequently, mutations in EXT1 and EXT2 genes with autosomal dominant inheritance are responsible for HME. In our group of 9 families with HME we evaluated the clinical course of the disease and analysed molecular background using Sanger sequencing and MLPA in EXT1 and EXT2 genes. The mean age in our group of patients, when the first exostosis was recognised was 4.5 years (range 2-10 years) and the number of exostoses per one patient documented on X-ray ranged from 2 to 54. Most of the exostoses developed before the growth was completed and they were dominantly localised in the distal femurs, proximal tibia, proximal humerus and distal radius. In all patients, at least one to 8 surgeries were necessary due to complaints and local complications, but neither patient developed malignant transformation. In half of the patients, the disease resulted in short stature. DNA analyses were positive in 7 families. In five probands, different EXT1 gene mutations resulting in premature stop-codon (p.Gly124Argfs*65, p.Leu191*, p.Trp364Lysfs*11, p.Val371Glyfs*10, p.Leu490Profs*31) were found. In two probands, nonsense mutations were found in EXT2 gene (p.Val187Profs*115, p.Cys319fs*46). Five mutations have been novel and two mutations have occurred de novo in probands. Although the risk for malignant transformation is usually low, especially in patients with low number of exostoses, early diagnostics and longitudinal follow up of patients is of a big importance, because early surgery can prevent progression of secondary bone deformities.
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Affiliation(s)
- Karel Medek
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Jiří Zeman
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Tomáš Honzík
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Hana Hansíková
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Štěpánka Švecová
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Kamila Beránková
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Vendula Kučerová Vidrová
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | | | - Jiří Chomiak
- Department of Orthopaedics, First Faculty of Medicine, Charles University and Na Bulovce Hospital, Prague, Czech Republic
| | - Markéta Tesařová
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.
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29
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Pacifici M. Hereditary Multiple Exostoses: New Insights into Pathogenesis, Clinical Complications, and Potential Treatments. Curr Osteoporos Rep 2017; 15:142-152. [PMID: 28466453 PMCID: PMC5510481 DOI: 10.1007/s11914-017-0355-2] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
PURPOSE OF REVIEW Hereditary multiple exostoses (HME) is a complex musculoskeletal pediatric disorder characterized by osteochondromas that form next to the growth plates of many skeletal elements, including long bones, ribs, and vertebrae. Due to its intricacies and unresolved issues, HME continues to pose major challenges to both clinicians and biomedical researchers. The purpose of this review is to describe and analyze recent advances in this field and point to possible targets and strategies for future biologically based therapeutic intervention. RECENT FINDINGS Most HME cases are linked to loss-of-function mutations in EXT1 or EXT2 that encode glycosyltransferases responsible for heparan sulfate (HS) synthesis, leading to HS deficiency. Recent genomic inquiries have extended those findings but have yet to provide a definitive genotype-phenotype correlation. Clinical studies emphasize that in addition to the well-known skeletal problems caused by osteochondromas, HME patients can experience, and suffer from, other symptoms and health complications such as chronic pain and nerve impingement. Laboratory work has produced novel insights into alterations in cellular and molecular mechanisms instigated by HS deficiency and subtending onset and growth of osteochondroma and how such changes could be targeted toward therapeutic ends. HME is a rare and orphan disease and, as such, is being studied only by a handful of clinical and basic investigators. Despite this limitation, significant advances have been made in the last few years, and the future bodes well for deciphering more thoroughly its pathogenesis and, in turn, identifying the most effective treatment for osteochondroma prevention.
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Affiliation(s)
- Maurizio Pacifici
- Translational Research Program in Pediatric Orthopaedics, Abramson Research Center, 902D, Division of Orthopaedic Surgery, Department of Surgery, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
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Sinha S, Mundy C, Bechtold T, Sgariglia F, Ibrahim MM, Billings PC, Carroll K, Koyama E, Jones KB, Pacifici M. Unsuspected osteochondroma-like outgrowths in the cranial base of Hereditary Multiple Exostoses patients and modeling and treatment with a BMP antagonist in mice. PLoS Genet 2017; 13:e1006742. [PMID: 28445472 PMCID: PMC5425227 DOI: 10.1371/journal.pgen.1006742] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 05/10/2017] [Accepted: 04/05/2017] [Indexed: 11/18/2022] Open
Abstract
Hereditary Multiple Exostoses (HME) is a rare pediatric disorder caused by loss-of-function mutations in the genes encoding the heparan sulfate (HS)-synthesizing enzymes EXT1 or EXT2. HME is characterized by formation of cartilaginous outgrowths-called osteochondromas- next to the growth plates of many axial and appendicular skeletal elements. Surprisingly, it is not known whether such tumors also form in endochondral elements of the craniofacial skeleton. Here, we carried out a retrospective analysis of cervical spine MRI and CT scans from 50 consecutive HME patients that included cranial skeletal images. Interestingly, nearly half of the patients displayed moderate defects or osteochondroma-like outgrowths in the cranial base and specifically in the clivus. In good correlation, osteochondromas developed in the cranial base of mutant Ext1f/f;Col2-CreER or Ext1f/f;Aggrecan-CreER mouse models of HME along the synchondrosis growth plates. Osteochondroma formation was preceded by phenotypic alteration of cells at the chondro-perichondrial boundary and was accompanied by ectopic expression of major cartilage matrix genes -collagen 2 and collagen X- within the growing ectopic masses. Because chondrogenesis requires bone morphogenetic protein (BMP) signaling, we asked whether osteochondroma formation could be blocked by a BMP signaling antagonist. Systemic administration with LDN-193189 effectively inhibited osteochondroma growth in conditional Ext1-mutant mice. In vitro studies with mouse embryo chondrogenic cells clarified the mechanisms of LDN-193189 action that turned out to include decreases in canonical BMP signaling pSMAD1/5/8 effectors but interestingly, concurrent increases in such anti-chondrogenic mechanisms as pERK1/2 and Chordin, Fgf9 and Fgf18 expression. Our study is the first to reveal that the cranial base can be affected in patients with HME and that osteochondroma formation is amenable to therapeutic drug intervention.
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Affiliation(s)
- Sayantani Sinha
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Christina Mundy
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Till Bechtold
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Federica Sgariglia
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Mazen M. Ibrahim
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Paul C. Billings
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Kristen Carroll
- Shriner’s Hospital for Children, Salt Lake City, Utah, United States of America
- Department of Orthopaedics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Eiki Koyama
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Kevin B. Jones
- Department of Orthopaedics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
- Department of Oncological Sciences and Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
- * E-mail: (MP); (KBJ)
| | - Maurizio Pacifici
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- * E-mail: (MP); (KBJ)
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