1
|
Alexandrou A, Salameh N, Papaevripidou I, Nicolaou N, Myrianthopoulos P, Ketoni A, Kousoulidou L, Anastasiou AM, Evangelidou P, Tanteles GA, Sismani C. Hereditary multiple exostoses caused by a chromosomal inversion removing part of EXT1 gene. Mol Cytogenet 2023; 16:8. [PMID: 37217936 DOI: 10.1186/s13039-023-00638-0] [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: 01/10/2023] [Accepted: 05/07/2023] [Indexed: 05/24/2023] Open
Abstract
BACKGROUND Hereditary multiple exostoses (HME) is an autosomal dominant skeletal disorder characterized by the development of multiple, circumscript and usually symmetric bony protuberances called osteochondromas. Most HME are caused by EXT1 and EXT2 loss of function mutations. Most pathogenic mutations are nonsense followed by missense mutations and deletions. CASE PRESENTATION Here we report on a patient with a rare and complex genotype resulting in a typical HME phenotype. Initial point mutation screening in EXT1 and EXT2 genes by Sanger sequencing did not reveal any pathogenic variants. The patient along with the healthy parents was subsequently referred for karyotype and array-Comparative Genomic Hybridization (CGH) analyses. Chromosomal analysis revealed two independent de novo apparently balanced rearrangements: a balanced translocation between the long arms of chromosomes 2 and 3 at breakpoints 2q22 and 3q13.2 and a pericentric inversion with breakpoints at 8p23.1q24.1. Both breakpoints were confirmed by Fluorescence In Situ Hybridization (FISH). Subsequently, array-CGH revealed a novel heterozygous deletion within the EXT1 gene at one of the inversion breakpoints, rendering the inversion unbalanced. The mode of inheritance, as well as the size of the deletion were further investigated by Quantitative Real-time PCR (qPCR), defining the deletion as de novo and of 3.1 kb in size, removing exon 10 of EXT1. The inversion in combination with the 8p23.1 deletion most likely abolishes the transcription of EXT1 downstream of exon 10 hence resulting in a truncated protein. CONCLUSIONS The identification of a rare and novel genetic cause of HME, highlights the importance of additional comprehensive investigation of patients with typical clinical manifestations, even when EXT1 and EXT2 mutation analysis is negative.
Collapse
Affiliation(s)
- Angelos Alexandrou
- Cytogenetics and Genomics Department, The Cyprus Institute of Neurology and Genetics, 6 Iroon Avenue, 2371, Ayios Dometios, PO Box 23462, 1683, Nicosia, Cyprus
| | - Nicole Salameh
- Cytogenetics and Genomics Department, The Cyprus Institute of Neurology and Genetics, 6 Iroon Avenue, 2371, Ayios Dometios, PO Box 23462, 1683, Nicosia, Cyprus
| | - Ioannis Papaevripidou
- Cytogenetics and Genomics Department, The Cyprus Institute of Neurology and Genetics, 6 Iroon Avenue, 2371, Ayios Dometios, PO Box 23462, 1683, Nicosia, Cyprus
| | - Nayia Nicolaou
- Clinical Genetics Department, Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Panayiotis Myrianthopoulos
- Cytogenetics and Genomics Department, The Cyprus Institute of Neurology and Genetics, 6 Iroon Avenue, 2371, Ayios Dometios, PO Box 23462, 1683, Nicosia, Cyprus
| | - Andria Ketoni
- Cytogenetics and Genomics Department, The Cyprus Institute of Neurology and Genetics, 6 Iroon Avenue, 2371, Ayios Dometios, PO Box 23462, 1683, Nicosia, Cyprus
| | - Ludmila Kousoulidou
- Cytogenetics and Genomics Department, The Cyprus Institute of Neurology and Genetics, 6 Iroon Avenue, 2371, Ayios Dometios, PO Box 23462, 1683, Nicosia, Cyprus
| | - Anna-Maria Anastasiou
- Clinical Genetics Department, Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Paola Evangelidou
- Cytogenetics and Genomics Department, The Cyprus Institute of Neurology and Genetics, 6 Iroon Avenue, 2371, Ayios Dometios, PO Box 23462, 1683, Nicosia, Cyprus
| | - George A Tanteles
- Clinical Genetics Department, Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Carolina Sismani
- Cytogenetics and Genomics Department, The Cyprus Institute of Neurology and Genetics, 6 Iroon Avenue, 2371, Ayios Dometios, PO Box 23462, 1683, Nicosia, Cyprus.
| |
Collapse
|
2
|
Liu W, Shi X, Li Y, Qiao F, Wu Y. The identification of a novel frameshift insertion mutation in the EXT1 gene in a Chinese family with hereditary multiple exostoses. Clin Case Rep 2022; 10:e6298. [PMID: 36101782 PMCID: PMC9459098 DOI: 10.1002/ccr3.6298] [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: 12/27/2021] [Revised: 08/11/2022] [Accepted: 08/19/2022] [Indexed: 11/08/2022] Open
Abstract
To identify the pathogenic gene variation in a Chinese family with Hereditary Multiple Exostoses (HME). By examining blood-sourced DNA and clinical manifestations of the proband and his family members, the whole exome sequencing (WES) and Sanger sequencing were used to detect possibly pathogenic mutations. A novel heterozygous mutation (c.325dup) was identified in exon 1 of the exostosin 1 (EXT1) gene from the proband and the affected family members. And we found this mutation was absent in all the unaffected family members. This c.325dup mutation is in the exon 1 domain of the EXT1 gene and the change of p.C109Lfs*80 cause the early termination of protein translation. The identification of the novel frameshift insertion mutation (c.325dup) expands the mutation spectrum of HME, which provides new evidence for HME diagnosis.
Collapse
Affiliation(s)
- Wanlu Liu
- Department of Obstetrics and GynecologyTongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Xinwei Shi
- Department of Obstetrics and GynecologyTongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Yuqi Li
- Department of Obstetrics and GynecologyTongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Fuyuan Qiao
- Department of Obstetrics and GynecologyTongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Yuanyuan Wu
- Department of Obstetrics and GynecologyTongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
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.
Collapse
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
| |
Collapse
|
7
|
Long X, Li Z, Huang Y, Zhang L, Lv W, Teng Y, Linpeng S, Liang D, Wu L. Identification of pathogenic mutations in 6 Chinese families with multiple exostoses by whole-exome sequencing and multiplex ligation-dependent probe amplification: Case series. Medicine (Baltimore) 2019; 98:e15692. [PMID: 31096510 PMCID: PMC6531242 DOI: 10.1097/md.0000000000015692] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
RATIONALE Hereditary multiple exostoses (HMEs) is an autosomal dominant skeletal disorder. PATIENT CONCERNS Six probands of the 6 unrelated Han Chinese families were identified as having HME. These patients had exostoses at multiple sites and significantly affected joints malformation and movement. DIAGNOSES Hereditary multiple exostoses. INTERVENTIONS To detect the genetic mechanism of HME in 6 unrelated Chinese families, whole-exome sequencing (WES) and multiplex ligation-dependent probe amplification (MLPA) were used after genomic DNA was isolated from peripheral blood leucocytes. Point mutations identified by these methods were verified by Sanger sequencing after PCR amplification. OUTCOMES Six mutations in the EXT1 and EXT2 genes were identified, including a heterozygous deletion mutation from exon 2 to exon 8 (Family 1), a c.448C>T, p.(Gln150X) heterozygous nonsense mutation (Family 4), a c.1057-2A>T heterozygous splicing substitution (Family 5), and a c.1468dupC, p.(Leu490fs519X) (Family 6) heterozygous duplication mutation in the EXT1 gene in addition to a heterozygous deletion mutation from exon 2 to exon 3 (Family 2) and a c.1197C>G, p.(Tyr399X) heterozygous nonsense mutation (Family 3) in the EXT2 gene. LESSONS Overall, we identified 5 novel mutations and 1 recurrent mutation in the EXT1 and EXT2 genes in 6 Chinese families with HME. Our findings expand the mutational spectrum of the EXT1 and EXT2 genes and are useful for genetic counseling and prenatal diagnosis.
Collapse
Affiliation(s)
- Xigui Long
- Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University
| | - Zhuo Li
- Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University
| | - Yanru Huang
- Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University
| | - Li Zhang
- Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University
| | - Weigang Lv
- Hunan Jiahui Genetics Hospital, Changsha, Hunan, PR China
| | - Yanling Teng
- Hunan Jiahui Genetics Hospital, Changsha, Hunan, PR China
| | - Siyuan Linpeng
- Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University
| | - Desheng Liang
- Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University
- Hunan Jiahui Genetics Hospital, Changsha, Hunan, PR China
| | - Lingqian Wu
- Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University
- Hunan Jiahui Genetics Hospital, Changsha, Hunan, PR China
| |
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
Dumazet A, Launois C, Dury S, Sailhan F, Alifano M, Dewolf M, Lebargy F, Deslee G, Perotin JM. Hereditary multiple exostoses of the ribs as an uncommon cause of pneumothorax: A case report. Medicine (Baltimore) 2018; 97:e11894. [PMID: 30170381 PMCID: PMC6393102 DOI: 10.1097/md.0000000000011894] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
RATIONALE Hereditary multiple exostoses (HME) is a genetic musculoskeletal condition causing multiple exostoses. Rib location of exostosis can be complicated by thoracic injuries. PATIENT CONCERNS AND DIAGNOSES We report a case of pneumothorax in a 32-year-old man with a partial left-sided pneumothorax caused by an exostosis of the fourth and fifth ribs. INTERVENTIONS AND OUTCOMES Clinical and radiological presentations allowed a conservative management. A video-assisted thoracoscopic surgery was performed a few weeks later to avoid any recurrence. LESSONS Rib exostosis represents an unusual cause of pneumothorax. Any local modification of symptoms or size of the exostosis should lead to investigations in regard to chondrosarcoma transformation.
Collapse
Affiliation(s)
- Antoine Dumazet
- Department of Respiratory Diseases, University Hospital, Reims, France
| | - Claire Launois
- Department of Respiratory Diseases, University Hospital, Reims, France
| | - Sandra Dury
- Department of Respiratory Diseases, University Hospital, Reims, France
- EA 4683, Laboratoire D’immunologie et de Biotechnologies, UFR de Pharmacie, Reims
| | - Frédéric Sailhan
- Department of Orthopedic Surgery, Cochin Hospital, APHP, Paris Descartes University
| | - Marco Alifano
- Department of Thoracic Surgery, Cochin hospital, APHP, Paris Descartes University, Paris
| | - Maxime Dewolf
- Department of Respiratory Diseases, University Hospital, Reims, France
| | - François Lebargy
- Department of Respiratory Diseases, University Hospital, Reims, France
- EA 4683, Laboratoire D’immunologie et de Biotechnologies, UFR de Pharmacie, Reims
| | - Gaëtan Deslee
- Department of Respiratory Diseases, University Hospital, Reims, France
- INSERM UMRS 1250, University Hospital, Reims, France
| | - Jeanne-Marie Perotin
- Department of Respiratory Diseases, University Hospital, Reims, France
- INSERM UMRS 1250, University Hospital, Reims, France
| |
Collapse
|
10
|
Mărginean CO, Meliţ LE, Mărginean MO. Daughter and mother diagnosed with hereditary multiple exostoses: A case report and a review of the literature. Medicine (Baltimore) 2017; 96:e5824. [PMID: 28072741 PMCID: PMC5228701 DOI: 10.1097/md.0000000000005824] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
INTRODUCTION Hereditary multiple exostoses (HME) or osteochondromatosis is a rare autosomal dominant disease characterized by multiple osteochondromas and skeletal deformities. PATIENT CONCERNS & DIAGNOSES We present the case of a 5 years and 9 month-old patient who presented with inferior limb pain for approximately 6 months, associating also deformity of the right index finger for a month. Hand X-ray revealed a radiologic abnormality of the right radius, therefore the child was referred to our clinic for further investigations. The X-rays revealed multiple osteochondromas of the radius, metacarpal bones, hand phalangeal bones, femur, tibia, fibula, metatarsal bones, and foot phalangeal bones. We mention that the same radiological aspect was identified in the case of the patient's mother, undiagnosed until that moment. OUTCOMES The particularity of this case consists in identification of a rare genetic pathology, HME in a 5-year-old patient, without any known familial history, after the occurrence of a nontraumatic joint dislocation of the right index finger. CONCLUSION HME is a rare genetic condition, without a curative treatment, burdened by multiple complications, and whose diagnosis is usually established during childhood.
Collapse
|
11
|
Solc R, Klugerova M, Vcelak J, Baxova A, Kuklik M, Vseticka J, Beharka R, Hirschfeldova K. Mutation analysis of TRPS1 gene including core promoter, 5'UTR, and 3'UTR regulatory sequences with insight into their organization. Clin Chim Acta 2016; 464:30-36. [PMID: 27826100 DOI: 10.1016/j.cca.2016.11.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 11/01/2016] [Accepted: 11/04/2016] [Indexed: 11/19/2022]
Abstract
The TRPS1 protein is a potent regulator of proliferation, differentiation, and apoptosis. The TRPS1 gene aberrations are strongly associated with rare trichorhinophalangeal syndrome (TRPS) development. We have conducted MLPA analysis to capture deletion within the crucial 8q24.1 chromosomal region in combination with mutation analysis of TRPS1 gene including core promoter, 5'UTR, and 3'UTR sequences in nine TRPS patients. Low complexity or extent of untranslated regulatory sequences avoided them from analysis in previous studies. Amplicon based next generation sequencing used in our study bridge over these technical limitations. Finally, we have made extended in silico analysis of TRPS1 gene regulatory sequences organization. Single contiguous deletion and an intragenic deletion intervening several exons were detected. Mutation analysis revealed five TRPS1 gene aberrations (two structural rearrangements, two nonsense mutations, and one missense substitution) reaching the overall detection rate of 78%. Several polymorphic variants were detected within the analysed regulatory sequences but without proposed pathogenic effect. In silico analysis suggested alternative promoter usage and diverse expression effectivity for different TRPS1 transcripts. Haploinsufficiency of TRPS1 gene was responsible for most of the TRPS phenotype. Structure of TRPS1 gene regulatory sequences is indicative of generally low single allele expression and its tight control.
Collapse
Affiliation(s)
- Roman Solc
- Department of Anthropology and Human Genetics, Faculty of Science, Charles University in Prague, Vinicna 7, 128 43 Prague, Czech Republic.
| | - Michaela Klugerova
- Department of Anthropology and Human Genetics, Faculty of Science, Charles University in Prague, Vinicna 7, 128 43 Prague, Czech Republic.
| | - Josef Vcelak
- Department of Molecular Endocrinology, Institute of Endocrinology, Narodni 8, 116 94 Prague, Czech Republic.
| | - Alice Baxova
- Institute of Biology and Medical Genetics, 1st Faculty of Medicine and General University Hospital, Charles University in Prague, Albertov 4, 128 00 Prague, Czech Republic.
| | - Miloslav Kuklik
- Department of Molecular Endocrinology, Institute of Endocrinology, Narodni 8, 116 94 Prague, Czech Republic; Genetic Department Olsanska, 1st and 3rd Faculty of Medicine, Charles University in Prague, Olsanska 2666/7, 130 00 Prague, Czech Republic.
| | - Jan Vseticka
- Genetika Ostrava s.r.o., Korenskeho 1317/12, 702 00 Ostrava, Czech Republic.
| | - Rastislav Beharka
- Department of Medical Genetics, University Hospital Brno, Cernopolni 212/9, 625 00 Brno, Czech Republic.
| | - Katerina Hirschfeldova
- Institute of Biology and Medical Genetics, 1st Faculty of Medicine and General University Hospital, Charles University in Prague, Albertov 4, 128 00 Prague, Czech Republic.
| |
Collapse
|
12
|
Zhou Q, Yang C, Chen MJ, Li LZ. Detection of exostosin glycosyltransferase gene mutations in patients with non-hereditary osteochondromas of the mandibular condyle. Mol Clin Oncol 2016; 5:295-299. [PMID: 27588195 DOI: 10.3892/mco.2016.955] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 01/20/2016] [Indexed: 11/05/2022] Open
Abstract
Exostosin glycosyltransferase (EXT) 1 and EXT2 have been identified as causative genes in osteochondroma; however, it is not known whether these genes are also involved in condylar osteochondromas. The aim of this study was to identify EXT1 and EXT2 mutations in patients with non-hereditary osteochondromas of the mandibular condyle. DNA was obtained from resected tissues (cartilage cap) of 12 patients with solitary condylar osteochondromas. The exons, 3',5'-untranslated regions and intron-exon boundaries of EXT1 and EXT2 were amplified by polymerase chain reaction and the products were sequenced directly. Through direct sequencing, four genetic variations of EXT1 in 4 cases and three variations of EXT2 in 5 cases were identified. The intronic alteration of the EXT2 gene, occurring in 2 cases, was novel, whereas the other alterations had been previously reported. Nonsense somatic mutations were detected in tumor DNA. Our study extended the mutational spectrum in EXT1 and EXT2 and may facilitate a better understanding of the pathophysiology of condylar osteochondromas.
Collapse
Affiliation(s)
- Qin Zhou
- Department of Oral and Maxillofacial Surgery, Ninth People's Hospital, Shanghai Key Laboratory of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, P.R. China
| | - Chi Yang
- Department of Oral and Maxillofacial Surgery, Ninth People's Hospital, Shanghai Key Laboratory of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, P.R. China
| | - Min-Jie Chen
- Department of Oral and Maxillofacial Surgery, Ninth People's Hospital, Shanghai Key Laboratory of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, P.R. China
| | - Ling-Zhi Li
- Department of Stomatology, Huashan Hospital, Fudan University, Shanghai 200438, P.R. China
| |
Collapse
|
13
|
Ishimaru D, Gotoh M, Takayama S, Kosaki R, Matsumoto Y, Narimatsu H, Sato T, Kimata K, Akiyama H, Shimizu K, Matsumoto K. Large-scale mutational analysis in the EXT1 and EXT2 genes for Japanese patients with multiple osteochondromas. BMC Genet 2016; 17:52. [PMID: 26961984 PMCID: PMC4784393 DOI: 10.1186/s12863-016-0359-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 03/01/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Multiple osteochondroma (MO) is an autosomal dominant skeletal disorder characterized by the formation of multiple osteochondromas, and exostosin-1 (EXT1) and exostosin-2 (EXT2) are major causative genes in MO. In this study, we evaluated the genetic backgrounds and mutational patterns in Japanese families with MO. RESULTS We evaluated 112 patients in 71 families with MO. Genomic DNA was isolated from peripheral blood leucocytes. The exons and exon/intron junctions of EXT1 and EXT2 were directly sequenced after PCR amplification. Fifty-two mutations in 47 families with MO in either EXT1 or EXT2, and 42.3% (22/52) of mutations were novel mutations. Twenty-nine families (40.8%) had mutations in EXT1, and 15 families (21.1%) had mutations in EXT2. Interestingly, three families (4.2%) had mutations in both EXT1 and EXT2. Twenty-four families (33.8%) did not exhibit mutations in either EXT1 or EXT2. With regard to the types of mutations identified, 59.6% of mutations were inactivating mutations, and 38.5% of mutations were missense mutations. CONCLUSIONS We found that the prevalence of EXT1 mutations was greater than that of EXT2 mutations in Japanese MO families. Additionally, we identified 22 novel EXT1 and EXT2 mutations in this Japanese MO cohort. This study represents the variety of genotype in MO.
Collapse
Affiliation(s)
- Daichi Ishimaru
- Department of Orthopaedic Surgery, Gifu University, Graduate School of Medicine, 1-1, Yanagido, Gifu, 501-1194, Japan.
| | - Masanori Gotoh
- Research Center for Medical Glycoscience (RCMG), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan.
| | - Shinichiro Takayama
- Department of Orthopedic Surgery, National Research Institute for Child Health and Development, Tokyo, Japan.
| | - Rika Kosaki
- Division of Medical Genetics, National Center for Child Health and Development, Tokyo, Japan.
| | - Yoshihiro Matsumoto
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
| | - Hisashi Narimatsu
- Research Center for Medical Glycoscience (RCMG), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan.
| | - Takashi Sato
- Research Center for Medical Glycoscience (RCMG), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan.
| | - Koji Kimata
- Advanced Medical Research Center, Aichi Medical University, Nagakute, Aichi, Japan.
| | - Haruhiko Akiyama
- Department of Orthopaedic Surgery, Gifu University, Graduate School of Medicine, 1-1, Yanagido, Gifu, 501-1194, Japan.
| | | | - Kazu Matsumoto
- Department of Orthopaedic Surgery, Gifu University, Graduate School of Medicine, 1-1, Yanagido, Gifu, 501-1194, Japan.
| |
Collapse
|
14
|
Xia P, Xu H, Shi Q, Li D. Identification of a novel frameshift mutation of the EXT2 gene in a family with multiple osteochondroma. Oncol Lett 2015; 11:105-110. [PMID: 26870176 PMCID: PMC4727190 DOI: 10.3892/ol.2015.3844] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 10/02/2015] [Indexed: 01/31/2023] Open
Abstract
Multiple osteochondroma (MO), also known as multiple hereditary exostoses, is an autosomal dominant skeletal disorder with characteristic multiple cartilage-capped tumours (osteochondromas or exostoses) growing outward from the metaphyseal region of the long tubular bones. Mutations in exostosin glycosyltransferase 1 (EXT1) or EXT2 are the most commonly associated mutations with MO and are responsible for 70–95% of cases. In the present study, a genetic analysis was performed on a large family with MO using polymerase chain reaction and direct DNA sequencing of the entire coding regions of EXT1 and EXT2. Sanger sequencing identified a novel heterozygous frameshift mutation, c.119_120delCT (p.Thr40ArgfsX15), in exon 2 of the EXT2 gene in the proband and all other affected individuals, while this deleterious mutation was not detected in the healthy family members and normal controls. The c.119_120delCT mutation is located in the transmembrane region of the EXT2 protein and results in a truncated EXT2 protein lacking 665 amino acids at the C-terminus, which includes the critical exostosin and glycosyltransferase family 64 domains. Thus, the present study identified a novel causative frameshift mutation in EXT2 from a large MO family. This study is useful for extending the known mutational spectrum of EXT2, for understanding the genetic basis of MO in the patients studied, and for further application of mutation screening in the genetic counseling and subsequent prenatal diagnosis of this family.
Collapse
Affiliation(s)
- Peng Xia
- Department of Spinal Surgery, Orthopedics Hospital, The Second Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
| | - Haikun Xu
- Department of Cardiology, China-Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
| | - Qingyang Shi
- Center for Prenatal Diagnosis, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| | - Dejun Li
- Center for Prenatal Diagnosis, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| |
Collapse
|
15
|
Remde H, Kaminsky E, Werner M, Quinkler M. A patient with novel mutations causing MEN1 and hereditary multiple osteochondroma. Endocrinol Diabetes Metab Case Rep 2015; 2015:EDM140120. [PMID: 26515642 PMCID: PMC4621953 DOI: 10.1530/edm-14-0120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 02/25/2015] [Indexed: 01/03/2023] Open
Abstract
UNLABELLED We report of a male patient aged 32 years who presented with primary hyperparathyroidism. Three parathyroid glands were resected. At the age of 46 years, nervus facialis irritation was noted, and an MRI scan incidentally revealed a non-functioning pituitary adenoma with affection of the chiasma opticum. The patient underwent transsphenoidal operation resulting in pituitary insufficiency postoperatively. At the same time, primary hyperparathyroidism reoccurred and a parathyroid adenoma located at the thymus was resected. The mother of the patient died early due to multiple tumors. The patient was suspected to have multiple endocrine neoplasia type 1 (MEN1) and genetic analysis was performed. In addition, on clinical examination, multiple exostoses were noticed and an additional genetic analysis was performed. His father was reported to have multiple osteochondromas too. MEN1 was diagnosed in the patient showing a novel heterozygote mutation c.2T>A in exon 2, codon 1 (start codon ATG>AAG;p.Met1?) of the MEN1 gene. In genetic mutational analysis of the EXT1 gene, another not yet known mutation c.1418-2A>C was found in intron 5 of the EXT1 gene (heterozygotic). In conclusion, we report novel mutations of the EXT1 and the MEN1 genes causing hereditary multiple osteochondromas and MEN1 in one patient. LEARNING POINTS It is important to ask for the patient's family history in detail.Patients with MEN1 are characterized by the occurrence of tumors in multiple endocrine tissues and nonendocrine tissues, most frequently parathyroid (95%), enteropancreatic neuroendocrine (50%), and anterior pituitary (40%) tissues.Familiar MEN1 has a high degree of penetrance (80-95%) by the age over 50; however, combinations of the tumors may be different in members of the same family.Patients with EXT1 gene mutations should be monitored for possible transformation of bone lesions into osteochondrosarcoma.
Collapse
Affiliation(s)
- Hanna Remde
- Charité University Medicine , Berlin , Germany
| | - Elke Kaminsky
- Laboratory for Molecular Genetics , Hamburg , Germany
| | - Mathias Werner
- Institute of Pathology , HELIOS Klinikum Emil von Behring, Stiftung Oskar-Helene-Heim, Berlin , Germany
| | - Marcus Quinkler
- Endocrinology in Charlottenburg , Stuttgarter Platz 1, Berlin, D 10627 , Germany
| |
Collapse
|
16
|
Lin WD, Hwu WL, Wang CH, Tsai FJ. Mutant EXT1 in Taiwanese Patients with Multiple Hereditary Exostoses. Biomedicine (Taipei) 2014; 4:11. [PMID: 25520924 PMCID: PMC4265008 DOI: 10.7603/s40681-014-0011-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 05/03/2014] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Multiple hereditary exostoses (MHE) is characterized by multiple benign projections of bone capped by cartilage, most numerous in metaphyses of long bones. HME are usually inherited in autosomal dominant mode, chief genes EXT1 and EXT2. METHODS Two MHE patients were identified from clinic and enrolled in genetic study, complete coding regions of EXT1 and EXT2, including intron/exon boundaries, sequenced via DNA samples drawn from participants. RESULTS DNA sequencing revealed mutant EXT1 gene in both cases, within which frame-shift mutation c.447delC (p.Ser149fsX156) in exon1 and nonsense mutation c.2034T>G (p.Tyr678X) in exon10, emerged. Neither mutation was detected in control group. CONCLUSIONS Our results extended the spectrum of EXT1 mutations, revealing similar incidence of EXT1 and EXT2 in Taiwanese MHE patients.
Collapse
Affiliation(s)
- Wei-De Lin
- Department of Medical Research, China Medical University Hospital, Taichung, Taiwan ; School of Post Baccalaureate Chinese Medicine, China Medical University, Taichung, Taiwan
| | - Wuh-Liang Hwu
- Department of Pediatrics and Medical Genetics, National Taiwan University Hospital and National Taiwan University School of Medicine, Taipei, Taiwan
| | - Chung-Hsing Wang
- Department of Pediatrics, China Medical University Hospital, Taichung, Taiwan ; School of Medicine, China Medical University, Taichung, Taiwan
| | - Fuu-Jen Tsai
- Department of Medical Research, China Medical University Hospital, Taichung, Taiwan ; Department of Pediatrics, China Medical University Hospital, Taichung, Taiwan ; Department of Medical Genetics, China Medical University Hospital, Taichung, Taiwan ; School of Chinese Medicine, China Medical University, Taichung, Taiwan ; Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan ; Department of Pediatrics and Medical Genetics, China Medical University Hospital, No. 2, Yuh Der Road, 404 Taichung, Taiwan
| |
Collapse
|
17
|
Kang QL, Xu J, Zhang Z, He JW, Fu WZ, Zhang ZL. Mutation screening for the EXT1 and EXT2 genes in Chinese patients with multiple osteochondromas. Arch Med Res 2013; 44:542-8. [PMID: 24120389 DOI: 10.1016/j.arcmed.2013.09.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 09/19/2013] [Indexed: 12/26/2022]
Abstract
BACKGROUND AND AIMS Multiple osteochondromas (MO), an autosomal dominant skeletal disease, is characterized by the presence of multiple cartilage-capped bone tumors (exostoses). Two genes with mutations that are most commonly associated with MO have been identified as EXT1 and EXT2, which are Exostosin-1 and Exostosin-2. In this study, a variety of EXT1 and EXT2 gene mutations were identified in ten Chinese families with MO. METHODS We investigated ten unrelated Chinese families involving a total of 46 patients who exhibited typical features of MO. The coding exons of EXT1 and EXT2 were sequenced after PCR amplification in ten probands. Radiological investigation was conducted simultaneously. RESULTS Nine mutations were identified, five in EXT1 and four in EXT2, of which three were de novo mutations and six were novel mutations. One proband carried mutations in both EXT1 and EXT2 simultaneously, and three probands, including one sporadic case and two familial cases, had no detectable mutations. CONCLUSIONS Our findings are useful for extending the mutational spectrum in EXT1 and EXT2 and understanding the genetic basis of MO in Chinese patients.
Collapse
Affiliation(s)
- Qing-lin Kang
- Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, PR China
| | | | | | | | | | | |
Collapse
|
18
|
Sarrión P, Sangorrin A, Urreizti R, Delgado A, Artuch R, Martorell L, Armstrong J, Anton J, Torner F, Vilaseca MA, Nevado J, Lapunzina P, Asteggiano CG, Balcells S, Grinberg D. Mutations in the EXT1 and EXT2 genes in Spanish patients with multiple osteochondromas. Sci Rep 2013; 3:1346. [PMID: 23439489 PMCID: PMC3581825 DOI: 10.1038/srep01346] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 02/07/2013] [Indexed: 11/15/2022] Open
Abstract
Multiple osteochondromas is an autosomal dominant skeletal disorder characterized by the formation of multiple cartilage-capped tumours. Two causal genes have been identified, EXT1 and EXT2, which account for 65% and 30% of cases, respectively. We have undertaken a mutation analysis of the EXT1 and EXT2 genes in 39 unrelated Spanish patients, most of them with moderate phenotype, and looked for genotype-phenotype correlations. We found the mutant allele in 37 patients, 29 in EXT1 and 8 in EXT2. Five of the EXT1 mutations were deletions identified by MLPA. Two cases of mosaicism were documented. We detected a lower number of exostoses in patients with missense mutation versus other kinds of mutations. In conclusion, we found a mutation in EXT1 or in EXT2 in 95% of the Spanish patients. Eighteen of the mutations were novel.
Collapse
Affiliation(s)
- P Sarrión
- Department of Genetics, Faculty of Biology, Universitat de Barcelona, CIBERER, IBUB, Spain
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Jennes I, Zuntini M, Mees K, Palagani A, Pedrini E, De Cock G, Fransen E, Vanden Berghe W, Sangiorgi L, Wuyts W. Identification and functional characterization of the human EXT1 promoter region. Gene 2011; 492:148-59. [PMID: 22037484 DOI: 10.1016/j.gene.2011.10.034] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2011] [Revised: 10/02/2011] [Accepted: 10/11/2011] [Indexed: 01/02/2023]
Abstract
BACKGROUND Mutations in Exostosin-1 (EXT1) or Exostosin-2 (EXT2) cause the autosomal dominant disorder multiple osteochondromas (MO). This disease is mainly characterized by the appearance of multiple cartilage-capped protuberances arising from children's metaphyses and is known to display clinical inter- and intrafamilial variations. EXT1 and EXT2 are both tumor suppressor genes encoding proteins that function as glycosyltransferases, catalyzing the biosynthesis of heparan sulfate. At present, however, very little is known about the regulation of these genes. Two of the most intriguing questions concerning the pathogenesis of MO are how disruption of a ubiquitously expressed gene causes this cartilage-specific disease and how the clinical intrafamilial variation can be explained. Since mutations in the EXT1 gene are responsible for ~65% of the MO families with known causal mutation, our aim was to isolate and characterize the EXT1 promoter region to elucidate the transcriptional regulation of this tumor suppressor gene. METHODS In the present study, luciferase reporter gene assays were used to experimentally confirm the in silico predicted EXT1 core promoter region. Subsequently, we evaluated the effect of single nucleotide polymorphisms (SNP's) on EXT1 promoter activity and transcription factor binding using luciferase assays, electrophoretic mobility shift assays (EMSA), and enzyme-linked immunosorbent assays (ELISA). Finally, a genotype-phenotype study was performed with the aim to identify one or more genetic modifiers influencing the clinical expression of MO. RESULTS Transient transfection of HEK293 cells with a series of luciferase reporter constructs mapped the EXT1 core promoter at approximately -917 bp upstream of the EXT1 start codon, within a 123 bp region. This region is conserved in mammals and located within a CpG-island containing a CAAT- and a GT-box. A polymorphic G/C-SNP at -1158 bp (rs34016643) was demonstrated to be located in a USF1 transcription factor binding site, which is lost with the presence of the C-allele resulting in a ~56% increase in EXT1 promoter activity. A genotype-phenotype study was suggestive for association of the C-allele with shorter stature, but also with a smaller number of osteochondromas. CONCLUSIONS We provide for the first time insight into the molecular regulation of EXT1. Although a larger patient population will be necessary for statistical significance, our data suggest the polymorphism rs34016643, in close proximity of the EXT1 promoter, to be a potential regulatory SNP, which could be a primary modifier that might explain part of the clinical variation observed in MO patients.
Collapse
Affiliation(s)
- Ivy Jennes
- Department of Medical Genetics, University of Antwerp, and Antwerp University Hospital, Edegem, Belgium
| | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Jennes I, de Jong D, Mees K, Hogendoorn PCW, Szuhai K, Wuyts W. Breakpoint characterization of large deletions in EXT1 or EXT2 in 10 multiple osteochondromas families. BMC MEDICAL GENETICS 2011; 12:85. [PMID: 21703028 PMCID: PMC3152881 DOI: 10.1186/1471-2350-12-85] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 06/26/2011] [Indexed: 11/18/2022]
Abstract
Background Osteochondromas (cartilage-capped bone tumors) are by far the most commonly treated of all primary benign bone tumors (50%). In 15% of cases, these tumors occur in the context of a hereditary syndrome called multiple osteochondromas (MO), an autosomal dominant skeletal disorder characterized by the formation of multiple cartilage-capped bone tumors at children's metaphyses. MO is caused by various mutations in EXT1 or EXT2, whereby large genomic deletions (single-or multi-exonic) are responsible for up to 8% of MO-cases. Methods Here we report on the first molecular characterization of ten large EXT1- and EXT2-deletions in MO-patients. Deletions were initially indentified using MLPA or FISH analysis and were subsequently characterized using an MO-specific tiling path array, allele-specific PCR-amplification and sequencing analysis. Results Within the set of ten large deletions, the deleted regions ranged from 2.7 to 260 kb. One EXT2 exon 8 deletion was found to be recurrent. All breakpoints were located outside the coding exons of EXT1 and EXT2. Non-allelic homologous recombination (NAHR) mediated by Alu-sequences, microhomology mediated replication dependent recombination (MMRDR) and non-homologous end-joining (NHEJ) were hypothesized as the causal mechanisms in different deletions. Conclusions Molecular characterization of EXT1- and EXT2-deletion breakpoints in MO-patients indicates that NAHR between Alu-sequences as well as NHEJ are causal and that the majority of these deletions are nonrecurring. These observations emphasize once more the huge genetic variability which is characteristic for MO. To our knowledge, this is the first study characterizing large genomic deletions in EXT1 and EXT2.
Collapse
Affiliation(s)
- Ivy Jennes
- Department of Medical Genetics, University and University Hospital of Antwerp, 2650 Edegem, Belgium
| | | | | | | | | | | |
Collapse
|
21
|
Kim BS, Kim NK, Lee SH, Cho YM, Heo KN, Park EW, Yang BK, Yoon DH. Association Study Between the Polymorphisms of Exostosin-1 Gene and Economic Traits in Hanwoo. JOURNAL OF ANIMAL SCIENCE AND TECHNOLOGY 2011. [DOI: 10.5187/jast.2011.53.1.7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
22
|
Genetic models of osteochondroma onset and neoplastic progression: evidence for mechanisms alternative to EXT genes inactivation. Oncogene 2010; 29:3827-34. [DOI: 10.1038/onc.2010.135] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
23
|
Jennes I, Pedrini E, Zuntini M, Mordenti M, Balkassmi S, Asteggiano CG, Casey B, Bakker B, Sangiorgi L, Wuyts W. Multiple osteochondromas: mutation update and description of the multiple osteochondromas mutation database (MOdb). Hum Mutat 2010; 30:1620-7. [PMID: 19810120 DOI: 10.1002/humu.21123] [Citation(s) in RCA: 158] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Multiple osteochondromas (MO) is an autosomal dominant skeletal disease characterized by the formation of multiple cartilage-capped bone tumors growing outward from the metaphyses of long tubular bones. MO is genetically heterogeneous, and is associated with mutations in Exostosin-1 (EXT1) or Exostosin-2 (EXT2), both tumor-suppressor genes of the EXT gene family. All members of this multigene family encode glycosyltransferases involved in the adhesion and/or polymerization of heparin sulfate (HS) chains at HS proteoglycans (HSPGs). HSPGs have been shown to play a role in the diffusion of Ihh, thereby regulating chondrocyte proliferation and differentiation. EXT1 is located at 8q24.11-q24.13, and comprises 11 exons, whereas the 16 exon EXT2 is located at 11p12-p11. To date, an EXT1 or EXT2 mutation is detected in 70-95% of affected individuals. EXT1 mutations are detected in +/-65% of cases, versus +/-35% EXT2 mutations in MO patient cohorts. Inactivating mutations (nonsense, frame shift, and splice-site mutations) represent the majority of MO causing mutations (75-80%). In this article, the clinical aspects and molecular genetics of EXT1 and EXT2 are reviewed together with 895 variants in MO patients. An overview of the reported variants is provided by the online Multiple Osteochondromas Mutation Database (http://medgen.ua.ac.be/LOVD).
Collapse
Affiliation(s)
- Ivy Jennes
- Department of Medical Genetics, University and University Hospital of Antwerp, Antwerp, Belgium
| | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Abstract
Multiple osteochondromas (MO) is characterised by development of two or more cartilage capped bony outgrowths (osteochondromas) of the long bones. The prevalence is estimated at 1:50,000, and it seems to be higher in males (male-to-female ratio 1.5:1). Osteochondromas develop and increase in size in the first decade of life, ceasing to grow when the growth plates close at puberty. They are pedunculated or sessile (broad base) and can vary widely in size. The number of osteochondromas may vary significantly within and between families, the mean number of locations is 15-18. The majority are asymptomatic and located in bones that develop from cartilage, especially the long bones of the extremities, predominantly around the knee. The facial bones are not affected. Osteochondromas may cause pain, functional problems and deformities, especially of the forearm, that may be reason for surgical removal. The most important complication is malignant transformation of osteochondroma towards secondary peripheral chondrosarcoma, which is estimated to occur in 0.5-5%. MO is an autosomal dominant disorder and is genetically heterogeneous. In almost 90% of MO patients germline mutations in the tumour suppressor genes EXT1 or EXT2 are found. The EXT genes encode glycosyltransferases, catalyzing heparan sulphate polymerization. The diagnosis is based on radiological and clinical documentation, supplemented with, if available, histological evaluation of osteochondromas. If the exact mutation is known antenatal diagnosis is technically possible. MO should be distinguished from metachondromatosis, dysplasia epiphysealis hemimelica and Ollier disease. Osteochondromas are benign lesions and do not affect life expectancy. Management includes removal of osteochondromas when they give complaints. Removed osteochondromas should be examined for malignant transformation towards secondary peripheral chondrosarcoma. Patients should be well instructed and regular follow-up for early detection of malignancy seems justified. For secondary peripheral chondrosarcoma, en-bloc resection of the lesion and its pseudocapsule with tumour-free margins, preferably in a bone tumour referral centre, should be performed.
Collapse
Affiliation(s)
- Judith V M G Bovée
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands.
| |
Collapse
|
25
|
Hameetman L, Bovée JV, Taminiau AH, Kroon HM, Hogendoorn PC. Multiple osteochondromas: clinicopathological and genetic spectrum and suggestions for clinical management. Hered Cancer Clin Pract 2004; 2:161-73. [PMID: 20233460 PMCID: PMC2840003 DOI: 10.1186/1897-4287-2-4-161] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2004] [Accepted: 11/15/2004] [Indexed: 12/31/2022] Open
Abstract
Multiple Osteochondromas is an autosomal dominant disorder characterised by the presence of multiple osteochondromas and a variety of orthopaedic deformities. Two genes causative of Multiple Osteochondromas, Exostosin-1 (EXT1) and Exostosin-2 (EXT2), have been identified, which act as tumour suppressor genes. Osteochondroma can progress towards its malignant counterpart, secondary peripheral chondrosarcoma and therefore adequate follow-up of Multiple Osteochondroma patients is important in order to detect malignant transformation early.This review summarizes the considerable recent basic scientific and clinical understanding resulting in a multi-step genetic model for peripheral cartilaginous tumorigenesis. This enabled us to suggest guidelines for clinical management of Multiple Osteochondroma patients. When a patient is suspected to have Multiple Osteochondroma, the radiologic documentation, histology and patient history have to be carefully reviewed, preferably by experts and if indicated for Multiple Osteochondromas, peripheral blood of the patient can be screened for germline mutations in either EXT1 or EXT2. After the Multiple Osteochondroma diagnosis is established and all tumours are identified, a regular follow-up including plain radiographs and base-line bone scan are recommended.
Collapse
Affiliation(s)
- Liesbeth Hameetman
- Department of Pathology, Leiden University Medical Centre, Leiden, The Netherlands.
| | | | | | | | | |
Collapse
|
26
|
Wuyts W, Roland D, Lüdecke HJ, Wauters J, Foulon M, Van Hul W, Van Maldergem L. Multiple exostoses, mental retardation, hypertrichosis, and brain abnormalities in a boy with a de novo 8q24 submicroscopic interstitial deletion. AMERICAN JOURNAL OF MEDICAL GENETICS 2002; 113:326-32. [PMID: 12457403 DOI: 10.1002/ajmg.10845] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Multiple exostoses represent a genetically heterogeneous disorder that may occur isolated or as part of a complex contiguous gene syndrome such as Langer-Giedion syndrome on chromosome 8 and the proximal 11p deletion syndrome on chromosome 11. Here we describe a boy with multiple exostoses, hypertrichosis, mental retardation, and epilepsy due to a de novo deletion on chromosome 8q24. Molecular analysis revealed that the deletion interval overlaps with the Langer-Giedion syndrome and involves the EXT1 gene and additional genes located distal to EXT1, but probably not encompassing the TRPS1 gene located proximal to EXT1.
Collapse
Affiliation(s)
- Wim Wuyts
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium
| | | | | | | | | | | | | |
Collapse
|
27
|
Affiliation(s)
- S epica
- Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, 277 21 Libechov, Czech Republic
| | | | | |
Collapse
|
28
|
Abstract
Congenital disorders of glycosylation (CDG) are a rapidly growing group of genetic diseases that are due to defects in the synthesis of glycans and in the attachment of glycans to other compounds. Most CDG are multisystem diseases that include severe brain involvement. The CDG causing sialic acid deficiency of N-glycans can be diagnosed by isoelectrofocusing of serum sialotransferrins. An efficient treatment, namely oral D-mannose, is available for only one CDG (CDG-Ib). In many patients with CDG, the basic defect is unknown (CDG-x). Glycan structural analysis, yeast genetics, and knockout animal models are essential tools in the elucidation of novel CDG. Eleven primary genetic glycosylation diseases have been discovered and their basic defects identified: six in the N-glycan assembly, three in the N-glycan processing, and two in the O-glycan (glycosaminoglycan) assembly. This review summarizes their clinical, biochemical, and genetic characteristics and speculates on further developments in this field.
Collapse
Affiliation(s)
- J Jaeken
- Department of Paediatrics, Centre for Metabolic Disease, University of Leuven, Leuven, Belgium.
| | | |
Collapse
|
29
|
Sankaranarayanan K, Chakraborty R. Ionizing radiation and genetic risks. XII. The concept of "potential recoverability correction factor" (PRCF) and its use for predicting the risk of radiation-inducible genetic disease in human live births. Mutat Res 2000; 453:129-81. [PMID: 11024484 DOI: 10.1016/s0027-5107(00)00107-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Genetic risks of radiation exposure of humans are generally expressed as expected increases in the frequencies of genetic diseases over those that occur naturally in the population as a result of spontaneous mutations. Since human data on radiation-induced germ cell mutations and genetic diseases remain scanty, the rates derived from the induced frequencies of mutations in mouse genes are used for this purpose. Such an extrapolation from mouse data to the risk of genetic diseases will be valid only if the average rates of inducible mutations in human genes of interest and the average rates of induced mutations in mice are similar. Advances in knowledge of human genetic diseases and in molecular studies of radiation-induced mutations in experimental systems now question the validity of the above extrapolation. In fact, they (i) support the view that only in a limited number of genes in the human genome, induced mutations may be compatible with viability and hence recoverable in live births and (ii) suggest that the average rate of induced mutations in human genes of interest from the disease point of view will be lower than that assumed from mouse results. Since, at present, there is no alternative to the use of mouse data on induced mutation rates, there is a need to bridge the gap between these and the risk of potentially inducible genetic diseases in human live births. In this paper, we advance the concept of what we refer to here as "the potential recoverability correction factor" (PRCF) to bridge the above gap in risk estimation and present a method to estimate PRCF. In developing the concept of PRCF, we first used the available information on radiation-induced mutations recovered in experimental studies to define some criteria for assessing potential recoverability of induced mutations and then applied these to human genes on a gene-by-gene basis. The analysis permitted us to estimate unweighted PRCFs (i.e. the fraction of genes among the total studied that might contribute to recoverable induced mutations) and weighted PRCFs (i.e. PRCFs weighted by the incidences of the respective diseases). The estimates are: 0.15 (weighted) to 0.30 (unweighted) for autosomal dominant and X-linked diseases and 0.02 (weighted) to 0.09 (unweighted) for chronic multifactorial diseases. The PRCF calculations are unnecessary for autosomal recessive diseases since the risks projected for the first few generations even without using PRCFs are already very small. For congenital abnormalities, PRCFs cannot be reliably estimated. With the incorporation of PRCF into the equation used for predicting risk, the risk per unit dose becomes the product of four quantities (risk per unit dose=Px(1/DD)xMCxPRCF) where P is the baseline frequency of the genetic disease, 1/DD is the relative mutation risk per unit dose, MC is the mutation component and PRCF is the disease-class-specific potential recoverability correction factor instead of the first three (as has been the case thus far). Since PRCF is a fraction, it is obvious that the estimate of risk obtained with the revised risk equation will be smaller than previously calculated values.
Collapse
Affiliation(s)
- K Sankaranarayanan
- Department of Radiation Genetics and Chemical Mutagenesis, Leiden University Medical Centre, Sylvius Laboratories, Wassenaarseweg 72, 2333, AL Leiden, The Netherlands.
| | | |
Collapse
|
30
|
Abstract
Hereditary multiple exostoses (EXT) is an autosomal dominant disorder characterized by the formation of exostoses, which are cartilage-capped bony protuberances mainly located on long bones. Two genes, EXT1 and EXT2, and at least one other unidentified gene, are known to be involved in the formation of exostoses. To date, 49 different EXT1 and 25 different EXT2 mutations have been found in EXT patients, and there is evidence that mutations in these two genes are responsible for over 70% of the EXT cases. Among the 49 EXT1 mutations there are 9 nonsense, 21 frameshift, and 5 splice site mutations; 2 in-frame deletions of 1 and 5 amino acids respectively; and 12 missense mutations. For EXT2, 8 nonsense, 11 frameshift, 3 splice site and 3 missense mutations are described. The majority of these mutations are mutations causing loss of function, which is consistent with the presumed tumor suppressor function of the EXT genes.
Collapse
Affiliation(s)
- W Wuyts
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium.
| | | |
Collapse
|
31
|
Abstract
Many theories of osteochondroma pathogenesis have been advanced. Genetic research into the inherited multiple form, hereditary multiple exostoses, has revealed a new family of tumour suppressor genes denoted EXT. Patterns of EXT gene mutation in hereditary multiple exostoses, in solitary and multiple osteochondromas, and in chondrosarcoma are analogous to those found in other tumour suppressor genes responsible for family cancer traits and associated malignancies. With one exception, most features of osteochondroma behaviour are comparable to those of benign neoplasms. The neoplastic pathogenesis of osteochondromas provides an alternative to the traditional 'skeletal dysplasia' theory to explain the growth disturbance associated with hereditary multiple exostoses. Recent studies on the physiological function of EXT genes are reviewed and implications for osteochondroma 'cell-of-origin' theories are discussed.
Collapse
Affiliation(s)
- D E Porter
- Nuffield Department of Orthopaedic Surgery, University of Oxford, Nuffield Orthopaedic Centre, Headington, Oxford OX3 7LD, U.K
| | | |
Collapse
|
32
|
Van Esch H, Groenen P, Daw S, Poffyn A, Holvoet M, Scambler P, Fryns JP, Van de Ven W, Devriendt K. Partial DiGeorge syndrome in two patients with a 10p rearrangement. Clin Genet 1999; 55:269-76. [PMID: 10361989 DOI: 10.1034/j.1399-0004.1999.550410.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We describe 2 patients with a partial DiGeorge syndrome (facial dysmorphism, hypoparathyroidism, renal agenesis, mental retardation) and a rearrangement of chromosome 10p. The first patient carries a complex chromosomal rearrangement, with a reciprocal insertional translocation between the short arm of chromosome 10 and the long arm of chromosome 8, with karyotype 46, XY ins(8;10) (8pter 8q13::10p15-->10p14::8q24.1-->8qter) ins(10:8) (10pter--> 10p15::8q24.1-->8q13::10p14-->10qter). The karyotype of the second patient shows a terminal deletion of the short arm of chromosome 10. In both patients, the breakpoints on chromosome 10p reside outside the previously determined DiGeorge critical region II (DGCRII). This is in agreement with previous reports of patients with a terminal deletion of 10p with breakpoints distal to the DGCRII and renal malformations/hypoparathyroidism, and thus adds to evidence that these features may be caused by haploinsufficiency of one or more genes distal to the DGCRII.
Collapse
Affiliation(s)
- H Van Esch
- Laboratory for Molecular Oncology, Center for Human Genetics, University of Leuven and Flanders Interuniversity Institute for Biotechnology, Belgium
| | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Lin X, Gan L, Klein WH, Wells D. Expression and functional analysis of mouse EXT1, a homolog of the human multiple exostoses type 1 gene. Biochem Biophys Res Commun 1998; 248:738-43. [PMID: 9703997 DOI: 10.1006/bbrc.1998.9050] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hereditary multiple exostoses (EXT) is a genetically heterogeneous, autosomal dominant skeletal disorder. The gene for EXT1 maps to human chromosome 8q24.1 and encodes an evolutionary conserved protein that is a member of a multigene family. The mouse homolog of human EXT1 protein is 99% similar to its human counterpart. Here, we present the expression profiles of the mouse EXT1 gene. EXT1 mRNA is initially expressed at 6.5 days post-coitum (d.p.c.), which coincides with gastrulation of the mouse embryo. Whole mount in situ hybridization with 10.5 to 12.5 d.p.c. mouse embryos showed a high level of expression of EXT1 mRNA in developing limb buds. Epitope tagging experiments revealed the endoplasmic reticulum localization of EXT1 protein. This localization was consistent with a hydrophobic stretch of amino acids present at the N-terminal end of the EXT1 protein. These results provide novel information on the function of EXT1 and the etiology of hereditary multiple exostoses.
Collapse
Affiliation(s)
- X Lin
- Department of Biology and Biochemistry, University of Houston, Texas 77204, USA
| | | | | | | |
Collapse
|
34
|
Lyko F, Buiting K, Horsthemke B, Paro R. Identification of a silencing element in the human 15q11-q13 imprinting center by using transgenic Drosophila. Proc Natl Acad Sci U S A 1998; 95:1698-702. [PMID: 9465079 PMCID: PMC19156 DOI: 10.1073/pnas.95.4.1698] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Prader-Willi syndrome (PWS) and Angelman syndrome are neurogenetic disorders caused by the lack of a paternal or a maternal contribution from human chromosome 15q11-q13, respectively. Deletions in the transcription unit of the imprinted SNRPN gene have been found in patients who have PWS or Angelman syndrome because of a parental imprint switch failure in this chromosomal domain. It has been suggested that the SNRPN exon 1 region, which is deleted in the PWS patients, contains an imprint switch element from which the maternal and paternal epigenotypes of the 15q11-q13 domain originate. Using the model organism Drosophila, we show here that a fragment from this region can function as a silencer in transgenic flies. Repression was detected specifically from this element and could not be observed with control human sequences. Additional experiments allowed the delineation of the silencer to a fragment of 215 bp containing the SNRPN promoter region. These results provide an additional link between genomic imprinting and an evolutionary conserved silencing mechanism. We suggest that the identified element participates in the long range regulation of the imprinted 15q11-q13 domain or locally represses SNRPN expression from the maternal allele.
Collapse
Affiliation(s)
- F Lyko
- Zentrum für Molekulare Biologie Heidelberg, University of Heidelberg, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | | | | | | |
Collapse
|
35
|
Wuyts W, Van Hul W, De Boulle K, Hendrickx J, Bakker E, Vanhoenacker F, Mollica F, Lüdecke HJ, Sayli BS, Pazzaglia UE, Mortier G, Hamel B, Conrad EU, Matsushita M, Raskind WH, Willems PJ. Mutations in the EXT1 and EXT2 genes in hereditary multiple exostoses. Am J Hum Genet 1998; 62:346-54. [PMID: 9463333 PMCID: PMC1376901 DOI: 10.1086/301726] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hereditary multiple exostoses (EXT; MIM 133700) is an autosomal dominant bone disorder characterized by the presence of multiple benign cartilage-capped tumors (exostoses). Besides suffering complications caused by the pressure of these exostoses on the surrounding tissues, EXT patients are at an increased risk for malignant chondrosarcoma, which may develop from an exostosis. EXT is genetically heterogeneous, and three loci have been identified so far: EXT1, on chromosome 8q23-q24; EXT2, on 11p11-p12; and EXT3, on the short arm of chromosome 19. The EXT1 and EXT2 genes were cloned recently, and they were shown to be homologous. We have now analyzed the EXT1 and EXT2 genes, in 26 EXT families originating from nine countries, to identify the underlying disease-causing mutation. Of the 26 families, 10 families had an EXT1 mutation, and 10 had an EXT2 mutation. Twelve of these mutations have never been described before. In addition, we have reviewed all EXT1 and EXT2 mutations reported so far, to determine the nature, frequency, and distribution of mutations that cause EXT. From this analysis, we conclude that mutations in either the EXT1 or the EXT2 gene are responsible for the majority of EXT cases. Most of the mutations in EXT1 and EXT2 cause premature termination of the EXT proteins, whereas missense mutations are rare. The development is thus mainly due to loss of function of the EXT genes, consistent with the hypothesis that the EXT genes have a tumor- suppressor function.
Collapse
Affiliation(s)
- W Wuyts
- Department of Medical Genetics, University of Antwerp, Belgium
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Van Hul W, Wuyts W, Hendrickx J, Speleman F, Wauters J, De Boulle K, Van Roy N, Bossuyt P, Willems PJ. Identification of a third EXT-like gene (EXTL3) belonging to the EXT gene family. Genomics 1998; 47:230-7. [PMID: 9479495 DOI: 10.1006/geno.1997.5101] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Two homologous genes, EXT1 and EXT2, responsible for the development of benign multiple cartilagenous bone tumors (exostoses) on the long bones, have been identified in the past 2 years. Several arguments have been provided to support the hypothesis that these genes have tumor suppressor activity and that loss of function of these genes may contribute to the development of bone tumors. The recent identification of two EXT-like genes, EXTL1 and EXTL2, homologous to the EXT genes and to each other, revealed the existence of a larger family of genes. We now report the identification of a homologous EST (EST01365), not derived from the known EXT and EXTL genes, indicating the existence of one additional member of this gene family. We characterized this third EXT-like gene, EXTL3, and compared it with the other four members of the EXT-EXTL family. In view of its putative tumor suppressor function, the EXTL3 gene can be considered a candidate gene for the breast cancer locus on chromosome 8p12-p22.
Collapse
Affiliation(s)
- W Van Hul
- Department of Medical Genetics, University of Antwerp, Belgium.
| | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Philippe C, Porter DE, Emerton ME, Wells DE, Simpson AH, Monaco AP. Mutation screening of the EXT1 and EXT2 genes in patients with hereditary multiple exostoses. Am J Hum Genet 1997; 61:520-8. [PMID: 9326317 PMCID: PMC1715939 DOI: 10.1086/515505] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Hereditary multiple exostoses (HME), the most frequent of all skeletal dysplasias, is an autosomal dominant disorder characterized by the presence of multiple exostoses localized mainly at the end of long bones. HME is genetically heterogeneous, with at least three loci, on 8q24.1 (EXT1), 11p11-p13 (EXT2), and 19p (EXT3). Both the EXT1 and EXT2 genes have been cloned recently and define a new family of potential tumor suppressor genes. This is the first study in which mutation screening has been performed for both the EXT1 and EXT2 genes prior to any linkage analysis. We have screened 17 probands with the HME phenotype, for alterations in all translated exons and flanking intronic sequences, in the EXT1 and EXT2 genes, by conformation-sensitive gel electrophoresis. We found the disease-causing mutation in 12 families (70%), 7 (41%) of which have EXT1 mutations and 5 (29%) EXT2 mutations. Together with the previously described 1-bp deletion in exon 6, which is present in 2 of our families, we report five new mutations in EXT1. Two are missense mutations in exon 2 (G339D and R340C), and the other three alterations (a nonsense mutation, a frameshift, and a splicing mutation) are likely to result in truncated nonfunctional proteins. Four new mutations are described in EXT2. A missense mutation (D227N) was found in 2 different families; the other three alterations (two nonsense mutations and one frameshift mutation) lead directly or indirectly to premature stop codons. The missense mutations in EXT1 and EXT2 may pinpoint crucial domains in both proteins and therefore give clues for the understanding of the pathophysiology of this skeletal disorder.
Collapse
Affiliation(s)
- C Philippe
- The Wellcome Trust Centre for Human Genetics, University of Oxford, United Kingdom
| | | | | | | | | | | |
Collapse
|