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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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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.
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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
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Nozawa S, Inubushi T, Irie F, Takigami I, Matsumoto K, Shimizu K, Akiyama H, Yamaguchi Y. Osteoblastic heparan sulfate regulates osteoprotegerin function and bone mass. JCI Insight 2018; 3:89624. [PMID: 29415886 DOI: 10.1172/jci.insight.89624] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 01/10/2018] [Indexed: 02/05/2023] Open
Abstract
Bone remodeling is a highly coordinated process involving bone formation and resorption, and imbalance of this process results in osteoporosis. It has long been recognized that long-term heparin therapy often causes osteoporosis, suggesting that heparan sulfate (HS), the physiological counterpart of heparin, is somehow involved in bone mass regulation. The role of endogenous HS in adult bone, however, remains unclear. To determine the role of HS in bone homeostasis, we conditionally ablated Ext1, which encodes an essential glycosyltransferase for HS biosynthesis, in osteoblasts. Resultant conditional mutant mice developed severe osteopenia. Surprisingly, this phenotype is not due to impairment in bone formation but to enhancement of bone resorption. We show that osteoprotegerin (OPG), which is known as a soluble decoy receptor for RANKL, needs to be associated with the osteoblast surface in order to efficiently inhibit RANKL/RANK signaling and that HS serves as a cell surface binding partner for OPG in this context. We also show that bone mineral density is reduced in patients with multiple hereditary exostoses, a genetic bone disorder caused by heterozygous mutations of Ext1, suggesting that the mechanism revealed in this study may be relevant to low bone mass conditions in humans.
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Affiliation(s)
- Satoshi Nozawa
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA.,Department of Orthopedic Surgery, Gifu University, Gifu, Japan
| | - Toshihiro Inubushi
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Fumitoshi Irie
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Iori Takigami
- Department of Orthopedic Surgery, Gifu University, Gifu, Japan
| | - Kazu Matsumoto
- Department of Orthopedic Surgery, Gifu University, Gifu, Japan
| | - Katsuji Shimizu
- Department of Orthopedic Surgery, Gifu University, Gifu, Japan
| | | | - Yu Yamaguchi
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
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Reyes Fernandez PC, Replogle RA, Wang L, Zhang M, Fleet JC. Novel Genetic Loci Control Calcium Absorption and Femur Bone Mass as Well as Their Response to Low Calcium Intake in Male BXD Recombinant Inbred Mice. J Bone Miner Res 2016; 31:994-1002. [PMID: 26636428 PMCID: PMC4862900 DOI: 10.1002/jbmr.2760] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 11/24/2015] [Accepted: 12/02/2015] [Indexed: 12/30/2022]
Abstract
Low dietary calcium (Ca) intake during growth limits peak bone mass but physiological adaptation can prevent this adverse effect. To assess the genetic control on the physiologic response to dietary Ca restriction (RCR), we conducted a study in 51 BXD lines fed either 0.5% (basal) or 0.25% (low) Ca diets from ages 4 to 12 weeks (n = 8/line/diet). Ca absorption (CaAbs), femur bone mineral density (BMD), and bone mineral content (BMC) were examined. ANCOVA with body size as covariate was used to detect significant line and diet main effects, and line-by-diet interactions. Body size-corrected residuals were used for linkage mapping and to estimate heritability (h(2) ). Loci controlling the phenotypes were identified using composite interval mapping on each diet and for the RCR. h(2) of basal phenotypes (0.37-0.43) and their RCR (0.32-0.38) was moderate. For each phenotype, we identified multiple quantitative trait loci (QTL) on each diet and for the RCR. Several loci affected multiple traits: Chr 1 (88.3-90.6 cM, CaAbs, BMC), Chr 4 (45.8-49.2 cM, CaAbs, BMD, BMC), Chr 8 (28.6-31.6 cM, CaAbs, BMD, RCR), and Chr 15 (13.6-24 cM, BMD, BMC; 32.3-36 cM, CaAbs RCR, BMD). This suggests that gene clusters may regulate interdependent bone-related phenotypes. Using in silico expression QTL (eQTL) mapping and bioinformatic tools, we identified novel candidates for the regulation of bone under Ca stress (Ext1, Deptor), and for the first time, we report genes modulating Ca absorption (Inadl, Sc4mol, Sh3rf1, and Dennd3), and both Ca and bone metabolism (Tceanc2, Tll1, and Aadat). Our data reveal gene-by-diet interactions and the existence of novel relationships between bone and Ca metabolism during growth. © 2015 American Society for Bone and Mineral Research.
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Affiliation(s)
| | - Rebecca A Replogle
- Department of Nutrition Science, Purdue University, West Lafayette, IN, USA
| | - Libo Wang
- Department of Statistics, Purdue University, West Lafayette, IN, USA
| | - Min Zhang
- Department of Statistics, Purdue University, West Lafayette, IN, USA
| | - James C Fleet
- Department of Nutrition Science, Purdue University, West Lafayette, IN, USA
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Upadhyaya GK, Jain VK, Arya RK, Sinha S, Naik AK. Osteochondroma of Upper Dorsal Spine Causing Spastic Paraparesis in Hereditary Multiple Exostosis: A Case Report. J Clin Diagn Res 2015; 9:RD04-6. [PMID: 26816957 DOI: 10.7860/jcdr/2015/14963.6948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Accepted: 10/24/2015] [Indexed: 12/13/2022]
Abstract
Osteochondroma of the spine is rare. It may present in solitary or multiple form (hereditary multiple exostoses). Herein, we report a case of an 18-year-old male who was diagnosed with thoracic osteochondroma, originating from the D4 vertebra with intraspinal extension and spinal cord compression in hereditary multiple exostosis. The patient was managed with surgery. Complete tumour excision was done to relieve cord compression and recurrence. Postoperatively the patient's symptoms were improved. At 2.5 year follow-up patient is doing well without any recurrence.
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Affiliation(s)
- Gaurav Kumar Upadhyaya
- Senior Resident, Department of Orthopaedics, PGIMER & Dr. RML Hospital , New Delhi, India
| | - Vijay Kumar Jain
- Chief Medical Officer, Department of Orthopaedics, PGIMER & Dr. RML Hospital , New Delhi, India
| | - Rajendra Kumar Arya
- Associate Professor, Department of Orthopaedics, PGIMER & Dr. RML Hospital , New Delhi, India
| | - Skand Sinha
- Assistant Professor, Department of Orthopaedics, PGIMER & Dr. RML Hospital , New Delhi, India
| | - Ananta Kumar Naik
- Associate Professor, Department of Orthopaedics, PGIMER & Dr. RML Hospital , New Delhi, India
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Wiweger MI, de Andrea CE, Scheepstra KWF, Zhao Z, Hogendoorn PCW. Possible effects of EXT2 on mesenchymal differentiation--lessons from the zebrafish. Orphanet J Rare Dis 2014; 9:35. [PMID: 24628984 PMCID: PMC4004154 DOI: 10.1186/1750-1172-9-35] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 02/10/2014] [Indexed: 01/13/2023] Open
Abstract
Background Mutations in the EXT genes disrupt polymerisation of heparan sulphates (HS) and lead to the development of osteochondroma, an isolated/sporadic- or a multifocal/hereditary cartilaginous bone tumour. Zebrafish (Danio rerio) is a very powerful animal model which has shown to present the same cartilage phenotype that is commonly seen in mice model and patients with the rare hereditary syndrome, Multiple Osteochondroma (MO). Methods Zebrafish dackel (dak) mutant that carries a nonsense mutation in the ext2 gene was used in this study. A panel of molecular, morphological and biochemical analyses was used to assess at what step bone formation is affected and what mechanisms underlie changes in the bone formation in the ext2 mutant. Results During bone development in the ext2-/- zebrafish, chondrocytes fail to undergo terminal differentiation; and pre-osteoblasts do not differentiate toward osteoblasts. This inadequate osteogenesis coincides with increased deposition of lipids/fats along/in the vessels and premature adipocyte differentiation as shown by biochemical and molecular markers. Also, the ext2-null fish have a muscle phenotype, i.e. muscles are shorter and thicker. These changes coexist with misshapen bones. Normal expression of runx2 together with impaired expression of osterix and its master regulator - xbp1 suggest that unfolded protein responses might play a role in MO pathogenesis. Conclusions Heparan sulphates are required for terminal differentiation of the cartilaginous template and consecutive formation of a scaffold that is needed for further bone development. HS are also needed for mesenchymal cell differentiation. At least one copy of ext2 is needed to maintain the balance between bone and fat lineages, but homozygous loss of the ext2 function leads to an imbalance between cartilage, bone and fat lineages. Normal expression of runx2 and impaired expression of osterix in the ext2-/- fish indicate that HS are required by osteoblast precursors for their further differentiation towards osteoblastic lineage. Lower expression of xbp1, a master regulator of osterix, suggests that HS affect the ‘unfolded protein response’, a pathway that is known to control bone formation and lipid metabolism. Our observations in the ext2-null fish might explain the musculoskeletal defects that are often observed in MO patients.
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Wu Y, Xing X, Xu S, Ma H, Cao L, Wang S, Luo Y. Novel and recurrent mutations in the EXT1 and EXT2 genes in Chinese kindreds with multiple osteochondromas. J Orthop Res 2013; 31:1492-9. [PMID: 23629877 DOI: 10.1002/jor.22378] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 04/04/2013] [Indexed: 02/04/2023]
Abstract
Multiple osteochondromas (MO) is an autosomal dominant hereditary disorder caused by heterozygous germline mutations in the exostonsin-1 (EXT1) or exostosin-2 (EXT2) genes. In this study, we screened mutations in the EXT1/EXT2 genes in four Chinese MO kindreds by direct sequencing. Three point mutations were detected, including a nonsense mutation in the EXT2 gene (c.544C > T) and two splice site mutations in the EXT1 and EXT2 genes, respectively (EXT1: c.1883 + 1G > A and EXT2: c.1173 + 1G > T). Although splice site mutations constitute at least 10% of all mutations that cause MO, there has been limited research on their pathogenic effect on RNA processing due to poor availability of patient RNA samples. In this study, ex vivo and in vivo splicing assays were used to investigate the effect of EXT1 and EXT2 mutations on aberrant splicing at the mRNA level. Our results indicate that identified splice site mutations can cause either cryptic splice site usage or exon skipping.
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Affiliation(s)
- Yuhong Wu
- The Research Center for Medical Genomics, Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, 110001, China
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Outcome and Prognosis of Myelopathy and Radiculopathy From Osteochondroma in the Mobile Spine. ACTA ACUST UNITED AC 2013; 26:194-9. [DOI: 10.1097/bsd.0b013e31823eb239] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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9
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Weinstein T, Evron Z, Trebicz-Geffen M, Aviv M, Robinson D, Kollander Y, Nevo Z. β-D-xylosides stimulate GAG synthesis in chondrocyte cultures due to elevation of the extracellular GAG domains, accompanied by the depletion of the intra-pericellular GAG pools, with alterations in the GAG profiles. Connect Tissue Res 2011; 53:169-79. [PMID: 22149722 DOI: 10.3109/03008207.2011.620190] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The familial disease of hereditary multiple exostoses is characterized by abnormal skeletal deformities requiring extensive surgical procedures. In hereditary multiple exostoses patients there is a shortage in the pericellular glycosaminoglycan (GAG) of heparan sulfate (HS), related to defective activity of HS glycosyltransferases, mainly in the pericellular regions of chondrocytes. This study searched for a novel approach employing xylosides with different aglycone groups priming a variety of GAG chains, in attempting to alter the GAG compositional profile. Cell cultures of patients with osteochondroma responded to p-nitrophenyl β-D-xyloside by a significant increase in total GAG synthesis, expressed mainly in the extracellular domains, limited to chondroitin sulfate). The different β-D-xylosides, in addition to increasing the synthesis of extracellular GAGs, led to a significant depletion of the intracellular GAG domains. In mouse chondrocyte cultures, β-D-xylosides with different aglycones created a unique distribution of the GAG pools. Of special interest was the finding that the naphthalene methanol β-D-xyloside showed the highest absolute levels of HS-GAGs in both extracellular and intra-pericellular moieties compared with other β-D-xylosides and with controls without xyloside. In summary, β-D-xylosides can be utilized in chondrocyte cultures to modify the distribution of GAGs between the extracellular and intracellular compartments. In addition, xylosides may alter the profile of specific GAG chains in each moiety.
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Affiliation(s)
- Talia Weinstein
- Department of Nephrology, Tel Aviv Sourasky Medical Center, Sackler School of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
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Vanita V, Sperling K, Sandhu HS, Sandhu PS, Singh JR. Novel EXT1 and EXT2 mutations in hereditary multiple exostoses families of Indian origin. Genet Test Mol Biomarkers 2009; 13:43-9. [PMID: 19309273 DOI: 10.1089/gtmb.2008.0055] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Hereditary multiple exostosis (HME) is an autosomal dominant bone disorder, characterized by short stature and the presence of multiple benign tumors mainly at the ends of long bones. HME is genetically heterogeneous with two known genes on 8q24 (EXT1) and 11p11 (EXT2), and a third minor locus mapped to 19p (EXT3). The majority of EXT1 and EXT2 mutations result in premature protein truncation and loss of function. MATERIALS AND METHODS We analyzed two autosomal dominant HME families of Indian origin. Linkage analysis using fluorescently labeled microsatellite markers at the candidate gene regions was performed. Mutation analysis was carried out by bidirectional sequencing of purified PCR products. RESULTS We found linkage in one family to EXT1 and in the other family to EXT2. Mutation screening in the EXT1 gene revealed a novel frameshift mutation, a single base deletion in exon 1 (c.142delC). This mutation segregated in all affected members and was absent in the unaffected family members and 60 unrelated controls. In the second family, a previously unreported stop mutation, the substitution c.817C>T, was observed in the EXT2 gene in all affected members and in none of the unaffected family members and 90 unrelated controls. CONCLUSIONS Our findings expand the mutation spectrum of EXT1 and EXT2 and highlight the genetic and phenotypic heterogeneity of HME.
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Affiliation(s)
- Vanita Vanita
- Centre for Genetic Disorders, Guru Nanak Dev University, Amritsar, India.
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Heinritz W, Hüffmeier U, Strenge S, Miterski B, Zweier C, Leinung S, Bohring A, Mitulla B, Peters U, Froster UG. New Mutations ofEXT1andEXT2Genes in German Patients with Multiple Osteochondromas. Ann Hum Genet 2009; 73:283-91. [DOI: 10.1111/j.1469-1809.2009.00508.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Xiong Q, Jiao Y, Hasty KA, Canale ST, Stuart JM, Beamer WG, Deng HW, Baylink D, Gu W. Quantitative trait loci, genes, and polymorphisms that regulate bone mineral density in mouse. Genomics 2009; 93:401-14. [PMID: 19150398 DOI: 10.1016/j.ygeno.2008.12.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Revised: 11/26/2008] [Accepted: 12/15/2008] [Indexed: 01/23/2023]
Abstract
This is an in silico analysis of data available from genome-wide scans. Through analysis of QTL, genes and polymorphisms that regulate BMD, we identified 82 BMD QTL, 191 BMD-associated (BMDA) genes, and 83 genes containing known BMD-associated polymorphisms (BMDAP). The catalogue of all BMDA/BMDAP genes and relevant literatures are provided. In total, there are substantially more BMDA/BMDAP genes in regions of the genome where QTL have been identified than in non-QTL regions. Among 191 BMDA genes and 83 BMDAP genes, 133 and 58 are localized in QTL regions, respectively. The difference was still noticeable for the chromosome distribution of these genes between QTL and non-QTL regions. These results have allowed us to generate an integrative profile of QTL, genes, polymorphisms that determine BMD. These data could facilitate more rapid and comprehensive identification of causal genes underlying the determination of BMD in mouse and provide new insights into how BMD is regulated in humans.
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Affiliation(s)
- Qing Xiong
- Department of Orthopaedic Surgery - Campbell Clinic and Pathology, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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Clément A, Wiweger M, von der Hardt S, Rusch MA, Selleck SB, Chien CB, Roehl HH. Regulation of zebrafish skeletogenesis by ext2/dackel and papst1/pinscher. PLoS Genet 2008; 4:e1000136. [PMID: 18654627 PMCID: PMC2453328 DOI: 10.1371/journal.pgen.1000136] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Accepted: 06/20/2008] [Indexed: 11/28/2022] Open
Abstract
Mutations in human Exostosin genes (EXTs) confer a disease called Hereditary Multiple Exostoses (HME) that affects 1 in 50,000 among the general population. Patients with HME have a short stature and develop osteochondromas during childhood. Here we show that two zebrafish mutants, dackel (dak) and pinscher (pic), have cartilage defects that strongly resemble those seen in HME patients. We have previously determined that dak encodes zebrafish Ext2. Positional cloning of pic reveals that it encodes a sulphate transporter required for sulphation of glycans (Papst1). We show that although both dak and pic are required during cartilage morphogenesis, they are dispensable for chondrocyte and perichondral cell differentiation. They are also required for hypertrophic chondrocyte differentiation and osteoblast differentiation. Transplantation analysis indicates that dak−/− cells are usually rescued by neighbouring wild-type chondrocytes. In contrast, pic−/− chondrocytes always act autonomously and can disrupt the morphology of neighbouring wild-type cells. These findings lead to the development of a new model to explain the aetiology of HME. Hereditary Multiple Exostoses is a disease that causes the formation of benign bone tumours in children. Besides causing severe skeletal deformity, the bone tumours can compress nerves or other tissue resulting in chronic pain. Although the tumours can usually be surgically removed, they sometimes recur or are in positions that prevent surgery. We have identified two strains of zebrafish whose offspring have skeletal defects that resemble those of patients with Hereditary Multiple Exostoses. We have found that each strain carries a mutated form of an essential gene. Importantly, these two genes are also found in humans, and thus by analysing their function in zebrafish, we may shed light on their role in humans. Our study has elucidated the roles of these genes during normal skeletal development and has allowed us to generate a model for how genetic changes give rise to bone tumours in humans.
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Affiliation(s)
- Aurélie Clément
- MRC Centre for Developmental and Biomedical Genetics, University of Sheffield, Sheffield, United Kingdom
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Malgorzata Wiweger
- MRC Centre for Developmental and Biomedical Genetics, University of Sheffield, Sheffield, United Kingdom
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | | | - Melissa A. Rusch
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Scott B. Selleck
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Chi-Bin Chien
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, United States of America
- Brain Institute, University of Utah, Salt Lake City, Utah, United States of America
| | - Henry H. Roehl
- MRC Centre for Developmental and Biomedical Genetics, University of Sheffield, Sheffield, United Kingdom
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
- * E-mail:
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Genes and networks expressed in perioperative omental adipose tissue are correlated with weight loss from Roux-en-Y gastric bypass. Int J Obes (Lond) 2008; 32:1395-406. [PMID: 18645576 DOI: 10.1038/ijo.2008.106] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
CONTEXT Gastric bypass surgery is the most commonly performed bariatric surgical procedure in the United States. Variable weight loss following this relatively standardized intervention has been reported. To date, a method for reliable profiling of patients who will successfully sustain weight loss for the long term has not been established. In addition, the mechanisms of action in accomplishing major weight loss as well as the explanation for the variable weight loss have not been established. OBJECTIVE To examine whether gene expression in perioperative omental adipose is associated with gastric bypass-induced weight loss. DESIGN Cross-sectional study of gene expression in perisurgical omental adipose tissues taken/available at the time of operation and total excess weight loss (EWL). SUBJECTS Fifteen overweight individuals who underwent Roux-en-Y gastric bypass (RYGB) surgery at the University of California Davis Medical Center (BMI: 40.6-72.8 kg/m(2)). MEASUREMENTS Body weight before and following weight stabilization 18-42 months after surgery. Perioperative omental adipose RNA isolated from 15 subjects was hybridized to Affymetrix HG-U133A chips for 22,283 transcript expression measurements. RESULTS Downstream analysis identified a set of genes whose expression was significantly correlated with RYGB-induced weight loss. The significant individual genes include acyl-coenzyme A oxidase 1 (ACOX1), phosphodiesterase 3A cGMP-inhibited (PDE3A) and protein kinase, AMP-activated, beta 1 non-catalytic subunit (PRKAB1). Specifically, ACOX1 plays a role in fatty acid metabolism. PDE3A is involved in purine metabolism and hormone-stimulated lipolysis. PRKAB1 is involved in adipocytokine signaling pathway. Gene network analysis revealed that pathways for glycerolipid metabolism, breast cancer and apoptosis were significantly correlated with long-term weight loss. CONCLUSION This study demonstrates that RNA expression profiles from perioperative adipose tissue are associated with weight loss outcome following RYGB surgery. Our data suggest that EWL could be predicted from preoperative samples, which would allow for informed decisions about whether or not to proceed to surgery.
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Trebicz-Geffen M, Robinson D, Evron Z, Glaser T, Fridkin M, Kollander Y, Vlodavsky I, Ilan N, Law KF, Cheah KSE, Chan D, Werner H, Nevo Z. The molecular and cellular basis of exostosis formation in hereditary multiple exostoses. Int J Exp Pathol 2008; 89:321-31. [PMID: 18452536 DOI: 10.1111/j.1365-2613.2008.00589.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The different clinical entities of osteochondromas, hereditary multiple exostoses (HME) and non-familial solitary exostosis, are known to express localized exostoses in their joint metaphyseal cartilage. In the current study biopsies of osteochondromas patients were screened with respect to a number of cellular and molecular parameters. Specifically, cartilaginous biopsy samples of nine HME patients, 10 solitary exostosis patients and 10 articular cartilages of control subjects were collected and cell cultures were established. Results obtained showed that one of the two HME samples that underwent DNA sequencing analysis (HME-1) had a novel mutation for an early stop codon, which led to an aberrant protein, migrating at a lower molecular weight position. The EXT-1 mRNA and protein levels in chondrocyte cultures derived from all nine HME patients were elevated, compared with solitary exostosis patients or control subjects. Furthermore, cell cultures of HME patients had significantly decreased pericellular heparan sulphate (HS) in comparison with cultures of solitary exostosis patients or control subjects. Immunohistochemical staining of tissue sections and Western blotting of cell cultures derived from HME patients revealed higher levels of heparanase compared with solitary exostosis patients and of control subjects. Further investigations are needed to determine whether the low pericellular HS levels in HME patients stem from decreased biosynthesis of HS, increased degradation or a combination of both. In conclusion, it appears that due to a mutated glycosyltransferase, the low content of pericellular HS in HME patients leads to the anatomical deformations with exostoses formation. Hence, elevation of HS content in the pericellular regions should be a potential molecular target for correction.
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Affiliation(s)
- Meirav Trebicz-Geffen
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
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Shen H, Long JR, Xiong DH, Guo YF, Xiao P, Liu YZ, Zhao LJ, Liu YJ, Deng HY, Li JL, Recker RR, Deng HW. A genomewide scan for quantitative trait loci underlying areal bone size variation in 451 Caucasian families. J Med Genet 2006; 43:873-80. [PMID: 16825438 PMCID: PMC2563191 DOI: 10.1136/jmg.2006.041251] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2006] [Revised: 05/02/2006] [Accepted: 05/18/2006] [Indexed: 11/03/2022]
Abstract
BACKGROUND Bone size is an important determinant of bone strength and is under strong genetic control. OBJECTIVE To identify quantitative trait loci (QTL) for areal bone size variation, a large-scale genomewide linkage scan was carried out in 451 Caucasian families. PARTICIPANTS AND METHODS Of 4124 people with phenotypes, 3899 were genotyped with 410 microsatellite markers. Multipoint linkage analyses were carried out in the entire sample, as well as in men and women separately. Potential epistatic interactions between identified genomic regions were also assessed. RESULTS Several potentially important genomic regions were identified, such as 8q24 for hip bone size (logarithm of the ratio of the odds that two loci are linked (LOD) 3.27) and 2p24 (LOD 2.04) for spine bone size. 8q24 may also interact with 19p13 to affect hip bone size. Several sex-specific QTL were also detected, such as 14q21 (LOD 2.94) for wrist bone size in women and 16q12 (LOD 2.19) for hip bone size in men. CONCLUSIONS Together with previous findings, this study has further delineated the genetic basis of bone size and laid a foundation for future studies to eventually elucidate the mechanisms of bone size regulation and associated fracture risks.
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