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Yang Y, Zhu G, Chen F, Zhu Y. Congenital middle radioulnar synostosis: Report of a probable subtype. J Orthop Sci 2023; 28:1189-1192. [PMID: 33906816 DOI: 10.1016/j.jos.2020.12.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 12/10/2020] [Accepted: 12/16/2020] [Indexed: 10/21/2022]
Affiliation(s)
- Yongjia Yang
- The Laboratory of Genetics and Metabolism, Hunan Children's Research Institute (HCRI), Hunan Children's Hospital, University of South China, Changsha, 410007, China.
| | - Guanghui Zhu
- Department of Orthopedics, Hunan Children's Hospital, University of South China, Changsha, 410007, China
| | - Fang Chen
- The Laboratory of Genetics and Metabolism, Hunan Children's Research Institute (HCRI), Hunan Children's Hospital, University of South China, Changsha, 410007, China
| | - Yimin Zhu
- The Laboratory of Genetics and Metabolism, Hunan Children's Research Institute (HCRI), Hunan Children's Hospital, University of South China, Changsha, 410007, China; Institute of Emergency Medicine, Hunan Provincial Key Laboratory of Emergency and Critical Care Metabonomics, Hunan Provincial People's Hospital (The First-affiliated Hospital of Hunan Normal University), Changsha, Hunan, China.
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2
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Cassim A, Hettiarachchi D, Dissanayake VHW. Genetic determinants of syndactyly: perspectives on pathogenesis and diagnosis. Orphanet J Rare Dis 2022; 17:198. [PMID: 35549993 PMCID: PMC9097448 DOI: 10.1186/s13023-022-02339-0] [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: 11/15/2021] [Accepted: 04/26/2022] [Indexed: 12/04/2022] Open
Abstract
The formation of the digits is a tightly regulated process. During embryogenesis, disturbance of genetic pathways in limb development could result in syndactyly; a common congenital malformation consisting of webbing in adjacent digits. Currently, there is a paucity of knowledge regarding the exact developmental mechanism leading to this condition. The best studied canonical interactions of Wingless‐type–Bone Morphogenic Protein–Fibroblast Growth Factor (WNT–BMP–FGF8), plays a role in the interdigital cell death (ICD) which is thought to be repressed in human syndactyly. Animal studies have displayed other pathways such as the Notch signaling, metalloprotease and non-canonical WNT-Planar cell polarity (PCP), to also contribute to failure of ICD, although less prominence has been given. The current diagnosis is based on a clinical evaluation followed by radiography when indicated, and surgical release of digits at 6 months of age is recommended. This review discusses the interactions repressing ICD in syndactyly, and characterizes genes associated with non-syndromic and selected syndromes involving syndactyly, according to the best studied canonical WNT-BMP-FGF interactions in humans. Additionally, the controversies regarding the current syndactyly classification and the effect of non-coding elements are evaluated, which to our knowledge has not been previously highlighted. The aim of the review is to better understand the developmental process leading to this condition.
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Affiliation(s)
- Afraah Cassim
- Human Genetics Unit, Faculty of Medicine, University of Colombo, 25, Kynsey Road, Colombo, Sri Lanka.
| | - Dineshani Hettiarachchi
- Human Genetics Unit, Faculty of Medicine, University of Colombo, 25, Kynsey Road, Colombo, Sri Lanka
| | - Vajira H W Dissanayake
- Human Genetics Unit, Faculty of Medicine, University of Colombo, 25, Kynsey Road, Colombo, Sri Lanka
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3
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Zaib T, Rashid H, Khan H, Zhou X, Sun P. Recent Advances in Syndactyly: Basis, Current Status and Future Perspectives. Genes (Basel) 2022; 13:771. [PMID: 35627156 PMCID: PMC9141913 DOI: 10.3390/genes13050771] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 02/05/2023] Open
Abstract
A comprehensive summary of recent knowledge in syndactyly (SD) is important for understanding the genetic etiology of SD and disease management. Thus, this review article provides background information on SD, as well as insights into phenotypic and genetic heterogeneity, newly identified gene mutations in various SD types, the role of HOXD13 in limb deformities, and recently introduced modern surgical techniques for SD. This article also proposes a procedure for genetic analysis to obtain a clearer genotype-phenotype correlation for SD in the future. We briefly describe the classification of non-syndromic SD based on variable phenotypes to explain different phenotypic features and mutations in the various genes responsible for the pathogenesis of different types of SD. We describe how different types of mutation in HOXD13 cause various types of SD, and how a mutation in HOXD13 could affect its interaction with other genes, which may be one of the reasons behind the differential phenotypes and incomplete penetrance. Furthermore, we also discuss some recently introduced modern surgical techniques, such as free skin grafting, improved flap techniques, and dermal fat grafting in combination with the Z-method incision, which have been successfully practiced clinically with no post-operative complications.
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Affiliation(s)
- Tahir Zaib
- Stem Cell Research Center, Shantou University Medical College, Shantou 515041, China
- (T.Z.)
- (X.Z.)
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou 515041, China
| | - Hibba Rashid
- Department of Biotechnology and Microbiology, Abasyn University, Peshawar 25000, Pakistan
| | - Hanif Khan
- Department of Pharmacology, Shantou University Medical College, Shantou 515041, China
| | - Xiaoling Zhou
- Stem Cell Research Center, Shantou University Medical College, Shantou 515041, China
- (T.Z.)
- (X.Z.)
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou 515041, China
| | - Pingnan Sun
- Stem Cell Research Center, Shantou University Medical College, Shantou 515041, China
- (T.Z.)
- (X.Z.)
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou 515041, China
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4
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Liao CD, Yamin F, Simpson RL. Correction of 4 th and 5 th metacarpal synostosis in a skeletally mature hand using de-rotational osteotomies. Case Reports Plast Surg Hand Surg 2022; 9:15-21. [PMID: 34993272 PMCID: PMC8725938 DOI: 10.1080/23320885.2021.2011290] [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] [Indexed: 11/17/2022]
Abstract
We present the successful surgical treatment and management of metacarpal synostosis in a near-skeletally mature 15-year-old patient, the significance of which is underscored by an updated review of the literature. We additionally outline a reliable surgical approach for patients with similar clinical presentations and disease severity.
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Affiliation(s)
- Christopher D Liao
- Division of Plastic and Reconstructive Surgery, Nassau University Medical Center, East Meadow, NY, USA
| | - Feras Yamin
- Division of Plastic and Reconstructive Surgery, Nassau University Medical Center, East Meadow, NY, USA
| | - Roger L Simpson
- Division of Plastic and Reconstructive Surgery, Nassau University Medical Center, East Meadow, NY, USA
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5
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Patel R, Singh SK, Bhattacharya V, Ali A. Novel HOXD13 variants in syndactyly type 1b and type 1c, and a new spectrum of TP63-related disorders. J Hum Genet 2021; 67:43-49. [PMID: 34321610 DOI: 10.1038/s10038-021-00963-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 07/09/2021] [Indexed: 12/15/2022]
Abstract
Syndactyly is the most common limb defect depicting the bony and/or cutaneous fusion of digits. Syndactyly can be of various types depending on the digits involved in the fusion. To date, eight syndactyly-associated genes have been reported, of which HOXD13 and GJA1 have been explored in a few syndactyly but most of them have unknown underlying genetics. In the present study HOXD13, GJA1 and TP63 genes have been screened by resequencing in 24 unrelated sporadic cases with various syndactyly. The screening revealed two pathogenic HOXD13 variants, NM_000523:c.500 A > G [p.(Y167C)], and NM_000523:c.961 A > C [p.(T321P)] in syndactyly type 1b and type 1c, respectively. This is the first report to identify HOXD13 pathogenic variant in syndactyly type 1b and third report in syndactyly type 1c pathogenesis. Furthermore, this study also reports a TP63 pathogenic variant, NM_003722:c.953 G > A [p.(R318H)] in Ectrodactyly and Cleft lip and palate (ECLP). In conclusion, the current study expands the clinical spectrum of HOXD13 and TP63-related disorders.
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Affiliation(s)
- Rashmi Patel
- Centre for Genetic Disorders, Institute of Science, Banaras Hindu University, Varanasi, India.,National Cancer Institute, Frederick, NIH, USA
| | | | - Visweswar Bhattacharya
- Department of Plastic Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
| | - Akhtar Ali
- Centre for Genetic Disorders, Institute of Science, Banaras Hindu University, Varanasi, India.
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Xie Y, Su N, Yang J, Tan Q, Huang S, Jin M, Ni Z, Zhang B, Zhang D, Luo F, Chen H, Sun X, Feng JQ, Qi H, Chen L. FGF/FGFR signaling in health and disease. Signal Transduct Target Ther 2020; 5:181. [PMID: 32879300 PMCID: PMC7468161 DOI: 10.1038/s41392-020-00222-7] [Citation(s) in RCA: 310] [Impact Index Per Article: 77.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 05/28/2020] [Accepted: 06/15/2020] [Indexed: 12/13/2022] Open
Abstract
Growing evidences suggest that the fibroblast growth factor/FGF receptor (FGF/FGFR) signaling has crucial roles in a multitude of processes during embryonic development and adult homeostasis by regulating cellular lineage commitment, differentiation, proliferation, and apoptosis of various types of cells. In this review, we provide a comprehensive overview of the current understanding of FGF signaling and its roles in organ development, injury repair, and the pathophysiology of spectrum of diseases, which is a consequence of FGF signaling dysregulation, including cancers and chronic kidney disease (CKD). In this context, the agonists and antagonists for FGF-FGFRs might have therapeutic benefits in multiple systems.
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Affiliation(s)
- Yangli Xie
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, China.
| | - Nan Su
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, China
| | - Jing Yang
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, China
| | - Qiaoyan Tan
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, China
| | - Shuo Huang
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, China
| | - Min Jin
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, China
| | - Zhenhong Ni
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, China
| | - Bin Zhang
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, China
| | - Dali Zhang
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, China
| | - Fengtao Luo
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, China
| | - Hangang Chen
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, China
| | - Xianding Sun
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, China
| | - Jian Q Feng
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, TX, 75246, USA
| | - Huabing Qi
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, China.
| | - Lin Chen
- Department of Wound Repair and Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, China.
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7
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Shu X, Dong Z, Cheng L, Shu S. DNA hypermethylation of Fgf16 and Tbx22 associated with cleft palate during palatal fusion. J Appl Oral Sci 2019; 27:e20180649. [PMID: 31596367 PMCID: PMC6768118 DOI: 10.1590/1678-7757-2018-0649] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 02/17/2019] [Accepted: 03/12/2019] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE Cleft palate (CP) is a congenital birth defect caused by the failure of palatal fusion. Little is known about the potential role of DNA methylation in the pathogenesis of CP. This study aimed to explore the potential role of DNA methylation in the mechanism of CP. METHODOLOGY We established an all-trans retinoic acid (ATRA)-induced CP model in C57BL/6J mice and used methylation-dependent restriction enzymes (MethylRAD, FspEI) combined with high-throughput sequencing (HiSeq X Ten) to compare genome-wide DNA methylation profiles of embryonic mouse palatal tissues, between embryos from ATRA-treated vs. untreated mice, at embryonic gestation day 14.5 (E14.5) (n=3 per group). To confirm differentially methylated levels of susceptible genes, real-time quantitative PCR (qPCR) was used to correlate expression of differentially methylated genes related to CP. RESULTS We identified 196 differentially methylated genes, including 17,298 differentially methylated CCGG sites between ATRA-treated vs. untreated embryonic mouse palatal tissues (P<0.05, log2FC>1). The CP-related genes Fgf16 (P=0.008, log2FC=1.13) and Tbx22 (P=0.011, log2FC=1.64,) were hypermethylated. Analysis of Fgf16 and Tbx22, using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG), identified 3 GO terms and 1 KEGG pathway functionally related to palatal fusion. The qPCR showed that changes in expression level negatively correlated with methylation levels. CONCLUSIONS Taken together, these results suggest that hypermethylation of Fgf16 and Tbx22 is associated with decreased gene expression, which might be responsible for developmental failure of palatal fusion, eventually resulting in the formation of CP.
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Affiliation(s)
- Xuan Shu
- Second Affiliated Hospital of Shantou University Medical College, Cleft Lip and Palate Treatment Center, Shantou, Guangdong, China
| | - Zejun Dong
- Second Affiliated Hospital of Shantou University Medical College, Cleft Lip and Palate Treatment Center, Shantou, Guangdong, China
| | - Liuhanghang Cheng
- Second Affiliated Hospital of Shantou University Medical College, Cleft Lip and Palate Treatment Center, Shantou, Guangdong, China
| | - Shenyou Shu
- Second Affiliated Hospital of Shantou University Medical College, Cleft Lip and Palate Treatment Center, Shantou, Guangdong, China
- Corresponding address: Shenyou Shu Cleft Lip and Palate Treatment Center, Second Affiliated Hospital of Shantou University Medical College 69 Dongxia North Road, Jinping District, Shantou 515041 - China. Phone: +86-18023235288 - Fax: +86-0754-83141156 e-mail:
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8
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Ahmed H, Akbari H, Emami A, Akbari MR. Genetic Overview of Syndactyly and Polydactyly. PLASTIC AND RECONSTRUCTIVE SURGERY-GLOBAL OPEN 2017; 5:e1549. [PMID: 29263957 PMCID: PMC5732663 DOI: 10.1097/gox.0000000000001549] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 09/06/2017] [Indexed: 11/27/2022]
Abstract
Syndactyly and polydactyly-respectively characterized by fused and supernumerary digits-are among the most common congenital limb malformations, with syndactyly presenting at an estimated incidence of 1 in 2,000-3,000 live births and polydactyly at a frequency of 1 in approximately 700-1,000 live births. Despite their relatively regular manifestation in the clinic, the etiologies of syndactyly and polydactyly remain poorly understood because of their phenotypic and genetic diversity. Further, even though concrete knowledge of genotypic links has been established for some variants of syndactyly and polydactyly, there appears to be no single comprehensive published summary of all syndromic and nonsyndromic syndactyly and polydactyly presentations, and there is decidedly no resource that maps all syndromic and nonsyndromic syndactylies and polydactylies to their genetic bases. This gap in the literature problematizes comprehensive carrier screening and prenatal diagnosis and complicates novel diagnostic attempts. This review thus attempts to collect all that is known about the genetic bases of syndromic and nonsyndromic syndactylies and polydactylies, as well as to highlight the dactyly manifestations for which no genetic bases are as yet known. Then, having established a summation of existing and missing knowledge, this work briefly outlines the diagnostic techniques that a genetics-reinforced understanding of syndactyly and polydactyly could inform.
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Affiliation(s)
- Humayun Ahmed
- From the Women’s College Research Institute, Women’s College Hospital, University of Toronto, Toronto, Canada; Institute of Medical Science, University of Toronto, Toronto, Canada; Department of Plastic and Reconstructive Surgery, Hazrat Fatemeh Hospital, Burn Research Center, Iran University of Medical Sciences, Tehran, Iran; and Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
| | - Hossein Akbari
- From the Women’s College Research Institute, Women’s College Hospital, University of Toronto, Toronto, Canada; Institute of Medical Science, University of Toronto, Toronto, Canada; Department of Plastic and Reconstructive Surgery, Hazrat Fatemeh Hospital, Burn Research Center, Iran University of Medical Sciences, Tehran, Iran; and Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
| | - Abdolhasan Emami
- From the Women’s College Research Institute, Women’s College Hospital, University of Toronto, Toronto, Canada; Institute of Medical Science, University of Toronto, Toronto, Canada; Department of Plastic and Reconstructive Surgery, Hazrat Fatemeh Hospital, Burn Research Center, Iran University of Medical Sciences, Tehran, Iran; and Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
| | - Mohammad R. Akbari
- From the Women’s College Research Institute, Women’s College Hospital, University of Toronto, Toronto, Canada; Institute of Medical Science, University of Toronto, Toronto, Canada; Department of Plastic and Reconstructive Surgery, Hazrat Fatemeh Hospital, Burn Research Center, Iran University of Medical Sciences, Tehran, Iran; and Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
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Deng H, Tan T, He Q, Lin Q, Yang Z, Zhu A, Guan L, Xiao J, Song Z, Guo Y. Identification of a missense HOXD13 mutation in a Chinese family with syndactyly type I-c using exome sequencing. Mol Med Rep 2017; 16:473-477. [PMID: 28498426 DOI: 10.3892/mmr.2017.6576] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 02/02/2017] [Indexed: 11/05/2022] Open
Abstract
Syndactyly is one of the most common hereditary limb malformations, and is characterized by the fusion of specific fingers and/or toes. Syndactyly type I‑c is associated with bilateral cutaneous or bony webbing of the third and fourth fingers and occasionally of the third to fifth fingers, with normal feet. The aim of the present study was to identify the genetic basis of syndactyly type I‑c in four generations of a Chinese Han family by exome sequencing. Exome sequencing was conducted in the proband of the family, followed by direct sequencing of other family members of the same ancestry, as well as 100 ethnically‑matched, unrelated normal controls. A missense mutation, c.917G>A (p.R306Q), was identified in the homeobox D13 gene (HOXD13). Sanger sequencing verified the presence of this mutation in all of the affected family members. By contrast, this mutation was absent in the unaffected family members and the 100 ethnically‑matched normal controls. The results suggest that the c.917G>A (p.R306Q) mutation in the HOXD13 gene, may be responsible for syndactyly type I‑c in this family. Exome sequencing may therefore be a powerful tool for identifying mutations associated with syndactyly, which is a disorder with high genetic and clinical heterogeneity. The results provide novel insights into the etiology and diagnosis of syndactyly, and may influence genetic counseling and the clinical management of the disease.
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Affiliation(s)
- Hao Deng
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, Hunan 410013, P.R. China
| | - Ting Tan
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, Hunan 410013, P.R. China
| | - Quanyong He
- Department of Burn and Plastic Surgery, The Third Xiangya Hospital, Central South University, Changsha, Hunan 410013, P.R. China
| | - Qiongfen Lin
- BGI‑Shenzhen, Shenzhen, Guangdong 518083, P.R. China
| | - Zhijian Yang
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, Hunan 410013, P.R. China
| | - Anding Zhu
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, Hunan 410013, P.R. China
| | - Liping Guan
- BGI‑Shenzhen, Shenzhen, Guangdong 518083, P.R. China
| | - Jingjing Xiao
- BGI‑Shenzhen, Shenzhen, Guangdong 518083, P.R. China
| | - Zhi Song
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, Hunan 410013, P.R. China
| | - Yi Guo
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, Hunan 410013, P.R. China
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Cheng J, Fang Z, Yang H, Li Y, Tian H, Gong W, Chen T, Liu M, Li X, Jiang C. High-yield of biologically active recombinant human fibroblast growth factor-16 in E. coli and its mechanism of proliferation in NCL-H460 cells. Prep Biochem Biotechnol 2017; 47:720-729. [PMID: 28409700 DOI: 10.1080/10826068.2017.1315599] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Fibroblast growth factor-16 (FGF16) is a member of FGF9 subfamily, which plays key role in promoting mitosis and cell survival, and also involved in embryonic development, cell growth, tissue repair, morphogenesis, tumor growth, and invasion. However, the successful high-yield purification of recombinant human fibroblast growth factor-16 (rhFGF16) protein has not been reported. In addition, lung cancer is a major cause of cancer-related deaths, which threats people's lives and its incidence has continued to rise. Learning pathways or proteins, which involved in lung tumor progression will contribute to the development of early diagnosis and targeted therapy. FGF16 promoted proliferation and invasion behavior of SKOV-3 ovarian cancer cells, whose function may be similar in lung cancer. The hFGF16 was cloned into pET-3d and expressed in Escherichia coli BL21 (DE3) pLysS. Finally, obtained two forms of FGF16 that exhibited remarkable biological activity and the purity is over 95%, meanwhile, the yield of soluble 130 mg/100 g and insoluble 240 mg/100 g. Experiments demonstrated FGF16 could promote proliferation of NCL-H460 cells by activating Akt, Erk1/2, and p38 MAPK signaling, whereas JNK had no significant effect. In total, this optimized expression strategy enables significant quantity and activity of rhFGF16, thereby meeting its further pharmacological and clinical usages.
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Affiliation(s)
- Jiliang Cheng
- a School of Pharmaceutical Sciences , Wenzhou Medical University , Wenzhou , China
| | - Zhaoxiang Fang
- a School of Pharmaceutical Sciences , Wenzhou Medical University , Wenzhou , China
| | - Huanhuan Yang
- a School of Pharmaceutical Sciences , Wenzhou Medical University , Wenzhou , China
| | - Yong Li
- b College of Life and Environmental Science , Wenzhou University , Wenzhou , Zhejiang , China
| | - Haishan Tian
- a School of Pharmaceutical Sciences , Wenzhou Medical University , Wenzhou , China
| | - Weiyue Gong
- a School of Pharmaceutical Sciences , Wenzhou Medical University , Wenzhou , China
| | - Taotao Chen
- a School of Pharmaceutical Sciences , Wenzhou Medical University , Wenzhou , China
| | - Min Liu
- a School of Pharmaceutical Sciences , Wenzhou Medical University , Wenzhou , China
| | - Xiaokun Li
- a School of Pharmaceutical Sciences , Wenzhou Medical University , Wenzhou , China.,c Biomedicine Collaborative Innovation Center , Wenzhou University , Wenzhou , Zhejiang , China
| | - Chao Jiang
- a School of Pharmaceutical Sciences , Wenzhou Medical University , Wenzhou , China.,b College of Life and Environmental Science , Wenzhou University , Wenzhou , Zhejiang , China.,c Biomedicine Collaborative Innovation Center , Wenzhou University , Wenzhou , Zhejiang , China
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11
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Rulifson IC, Collins P, Miao L, Nojima D, Lee KJ, Hardy M, Gupte J, Hensley K, Samayoa K, Cam C, Rottman JB, Ollmann M, Richards WG, Li Y. In Vitro and in Vivo Analyses Reveal Profound Effects of Fibroblast Growth Factor 16 as a Metabolic Regulator. J Biol Chem 2016; 292:1951-1969. [PMID: 28011645 DOI: 10.1074/jbc.m116.751404] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 12/22/2016] [Indexed: 11/06/2022] Open
Abstract
The discovery of brown adipose tissue (BAT) as a key regulator of energy expenditure has sparked interest in identifying novel soluble factors capable of activating inducible BAT (iBAT) to combat obesity. Using a high content cell-based screen, we identified fibroblast growth factor 16 (FGF16) as a potent inducer of several physical and transcriptional characteristics analogous to those of both "classical" BAT and iBAT. Overexpression of Fgf16 in vivo recapitulated several of our in vitro findings, specifically the significant induction of the Ucp1 gene and UCP1 protein expression in inguinal white adipose tissue (iWAT), a common site for emergent active iBAT. Despite significant UCP1 up-regulation in iWAT and dramatic weight loss, the metabolic improvements observed due to Fgf16 overexpression in vivo were not the result of increased energy expenditure, as measured by indirect calorimetric assessment. Instead, a pattern of reduced food and water intake, combined with feces replete with lipid and bile acid, indicated a phenotype more akin to that of starvation and intestinal malabsorption. Gene expression analysis of the liver and ileum indicated alterations in several steps of bile acid metabolism, including hepatic synthesis and reabsorption. Histological analysis of intestinal tissue revealed profound abnormalities in support of this conclusion. The in vivo data, together with FGF receptor binding analysis, indicate that the in vivo outcome observed is the likely result of both direct and indirect mechanisms and probably involves multiple receptors. These results highlight the complexity of FGF signaling in the regulation of various metabolic processes.
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Affiliation(s)
- Ingrid C Rulifson
- From the Department of Cardiometabolic Disorders, South San Francisco, California 94080.
| | - Patrick Collins
- the Genome Analysis Unit, South San Francisco, California 94080
| | - Li Miao
- From the Department of Cardiometabolic Disorders, South San Francisco, California 94080
| | - Dana Nojima
- the Genome Analysis Unit, South San Francisco, California 94080
| | - Ki Jeong Lee
- the Genome Analysis Unit, Thousand Oaks, California 91320
| | - Miki Hardy
- the Genome Analysis Unit, South San Francisco, California 94080
| | - Jamila Gupte
- From the Department of Cardiometabolic Disorders, South San Francisco, California 94080
| | - Kelly Hensley
- the Department of Pathology, South San Francisco, California 94080
| | - Kim Samayoa
- the Department of Pathology, South San Francisco, California 94080
| | - Cynthia Cam
- the Department of Comparative Animal Research, Amgen Inc., South San Francisco, California 94080
| | - James B Rottman
- the Department of Pathology, Amgen Inc., Cambridge, Massachusetts 02142
| | - Mike Ollmann
- the Genome Analysis Unit, South San Francisco, California 94080
| | - William G Richards
- the Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, California 91320
| | - Yang Li
- From the Department of Cardiometabolic Disorders, South San Francisco, California 94080.
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12
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Abstract
Background: Carpal coalition and metacarpal synostosis are uncommon congenital anomalies of the carpus and hand. Methods: A comprehensive review of the literature was performed to help guide surgical and non-surgical treatment of carpal coalition and metacarpal synostosis. Results: The embryology, epidemiology, medical and surgical management, and associated outcomes are detailed. Conclusions: Most patients with these disorders will likely benefit from conservative measures. Surgery should be considered in patients with pain and limitations in wrist and hand function.
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Affiliation(s)
- Michael B. Gottschalk
- Emory School of Medicine, Department of Orthopaedics, Atlanta, GA, USA
- Michael B. Gottschalk, Assistant Professor Hand and Upper Extremity, Director of Clinical Research, 4555 N Shallowford Road Ste 100, Dunwoody, GA 30338, USA.
| | - Maxim Danilevich
- University of Texas Medical Branch School of Medicine, Galveston, USA
| | - Hilton P. Gottschalk
- Dell Children’s Medical Center, Austin, TX, USA
- Central Texas Pediatric Orthopedics, Austin, TX, USA
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13
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The long tail and rare disease research: the impact of next-generation sequencing for rare Mendelian disorders. Genet Res (Camb) 2015; 97:e15. [PMID: 26365496 DOI: 10.1017/s0016672315000166] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
There are an estimated 6000-8000 rare Mendelian diseases that collectively affect 30 million individuals in the United States. The low incidence and prevalence of these diseases present significant challenges to improving diagnostics and treatments. Next-generation sequencing (NGS) technologies have revolutionized research of rare diseases. This article will first comment on the effectiveness of NGS through the lens of long-tailed economics. We then provide an overview of recent developments and challenges of NGS-based research on rare diseases. As the quality of NGS studies improve and the cost of sequencing decreases, NGS will continue to make a significant impact on the study of rare diseases moving forward.
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14
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Deng H, Tan T. Advances in the Molecular Genetics of Non-syndromic Syndactyly. Curr Genomics 2015; 16:183-93. [PMID: 26069458 PMCID: PMC4460222 DOI: 10.2174/1389202916666150317233103] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/18/2015] [Accepted: 03/16/2015] [Indexed: 12/16/2022] Open
Abstract
Syndactyly, webbing of adjacent digits with or without bony fusion, is one of the most common hereditary limb malformations. It occurs either as an isolated abnormality or as a component of more than 300 syndromic anomalies. There are currently nine types of phenotypically diverse nonsyndromic syndactyly. Non-syndromic syndactyly is usually inherited as an autosomal dominant trait, although the more severe presenting types and subtypes may show autosomal recessive or X-linked pattern of inheritance. The phenotype appears to be not only caused by a main gene, but also dependant on genetic background and subsequent signaling pathways involved in limb formation. So far, the principal genes identified to be involved in congenital syndactyly are mainly involved in the zone of polarizing activity and sonic hedgehog pathway. This review summarizes the recent progress made in the molecular genetics, including known genes and loci responsible for non-syndromic syndactyly, and the signaling pathways those genetic factors involved in, as well as clinical features and animal models. We hope our review will contribute to the understanding of underlying pathogenesis of this complicated disorder and have implication on genetic counseling.
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Affiliation(s)
- Hao Deng
- Center for Experimental Medicine ; Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha, China
| | - Ting Tan
- Center for Experimental Medicine
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15
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Ornitz DM, Itoh N. The Fibroblast Growth Factor signaling pathway. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2015; 4:215-66. [PMID: 25772309 PMCID: PMC4393358 DOI: 10.1002/wdev.176] [Citation(s) in RCA: 1304] [Impact Index Per Article: 144.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 11/23/2014] [Accepted: 01/08/2015] [Indexed: 12/13/2022]
Abstract
The signaling component of the mammalian Fibroblast Growth Factor (FGF) family is comprised of eighteen secreted proteins that interact with four signaling tyrosine kinase FGF receptors (FGFRs). Interaction of FGF ligands with their signaling receptors is regulated by protein or proteoglycan cofactors and by extracellular binding proteins. Activated FGFRs phosphorylate specific tyrosine residues that mediate interaction with cytosolic adaptor proteins and the RAS-MAPK, PI3K-AKT, PLCγ, and STAT intracellular signaling pathways. Four structurally related intracellular non-signaling FGFs interact with and regulate the family of voltage gated sodium channels. Members of the FGF family function in the earliest stages of embryonic development and during organogenesis to maintain progenitor cells and mediate their growth, differentiation, survival, and patterning. FGFs also have roles in adult tissues where they mediate metabolic functions, tissue repair, and regeneration, often by reactivating developmental signaling pathways. Consistent with the presence of FGFs in almost all tissues and organs, aberrant activity of the pathway is associated with developmental defects that disrupt organogenesis, impair the response to injury, and result in metabolic disorders, and cancer. For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- David M Ornitz
- Department of Developmental Biology, Washington University School of MedicineSt. Louis, MO, USA
- *
Correspondence to:
| | - Nobuyuki Itoh
- Graduate School of Pharmaceutical Sciences, Kyoto UniversitySakyo, Kyoto, Japan
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16
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Wang J, Sontag D, Cattini PA. Heart-specific expression of FGF-16 and a potential role in postnatal cardioprotection. Cytokine Growth Factor Rev 2014; 26:59-66. [PMID: 25106133 DOI: 10.1016/j.cytogfr.2014.07.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 07/11/2014] [Accepted: 07/14/2014] [Indexed: 10/25/2022]
Abstract
Fibroblast growth factor 16 (FGF-16) was originally cloned from rat heart. Subsequent investigation of mouse FGF-16, including generation of null mice, revealed a specific pattern of expression in the endocardium and epicardium, and role for FGF-16 during embryonic heart development. FGF-16 is expressed mainly in brown adipose tissue during rat embryonic development, but is expressed mainly in the murine heart after birth. There is also an apparent switch from limited endocardial and epicardial expression in the embryo to the myocardium in the perinatal period. The FGF-16 gene and its location on the X chromosome are conserved between human and murine species, and no other member of the FGF family shows this pattern of spatial and temporal expression. The human and murine FGF-16 gene promoter regions also share an equivalent location for TATA sequences, as well as adjacent putative binding sites for transcription factors linked to cardiac expression and response to stress. Recent evidence has implicated nonsense mutation of FGF-16 with increased cardiovascular risk, and FGF-16 supplementation with cardioprotection. Here we review the important role of FGF-16 in embryonic heart development, its gene regulation, and evidence for FGF-16 as an endogenous and exogenous cardiac-specific and protective factor in the postnatal heart. Moreover, given the conservation of the FGF-16 gene and its chromosomal location between species, the question of support for a cardiac role in the human population is also considered.
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Affiliation(s)
- Jie Wang
- Department of Physiology & Pathophysiology, University of Manitoba, Manitoba, Canada.
| | - David Sontag
- Department of Physiology & Pathophysiology, University of Manitoba, Manitoba, Canada
| | - Peter A Cattini
- Department of Physiology & Pathophysiology, University of Manitoba, Manitoba, Canada
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17
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Laurell T, Nilsson D, Hofmeister W, Lindstrand A, Ahituv N, Vandermeer J, Amilon A, Annerén G, Arner M, Pettersson M, Jäntti N, Rosberg HE, Cattini PA, Nordenskjöld A, Mäkitie O, Grigelioniene G, Nordgren A. Identification of three novel FGF16 mutations in X-linked recessive fusion of the fourth and fifth metacarpals and possible correlation with heart disease. Mol Genet Genomic Med 2014; 2:402-11. [PMID: 25333065 PMCID: PMC4190875 DOI: 10.1002/mgg3.81] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Revised: 03/26/2014] [Accepted: 04/04/2014] [Indexed: 11/24/2022] Open
Abstract
Nonsense mutations in FGF16 have recently been linked to X-linked recessive hand malformations with fusion between the fourth and the fifth metacarpals and hypoplasia of the fifth digit (MF4; MIM#309630). The purpose of this study was to perform careful clinical phenotyping and to define molecular mechanisms behind X-linked recessive MF4 in three unrelated families. We performed whole-exome sequencing, and identified three novel mutations in FGF16. The functional impact of FGF16 loss was further studied using morpholino-based suppression of fgf16 in zebrafish. In addition, clinical investigations revealed reduced penetrance and variable expressivity of the MF4 phenotype. Cardiac disorders, including myocardial infarction and atrial fibrillation followed the X-linked FGF16 mutated trait in one large family. Our findings establish that a mutation in exon 1, 2 or 3 of FGF16 results in X-linked recessive MF4 and expand the phenotypic spectrum of FGF16 mutations to include a possible correlation with heart disease.
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Affiliation(s)
- Tobias Laurell
- Department of Molecular Medicine and Surgery and Center of Molecular Medicine, Karolinska Institutet Stockholm, Sweden ; Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet Stockholm, Sweden ; Department of Hand Surgery, Södersjukhuset Stockholm, Sweden
| | - Daniel Nilsson
- Department of Molecular Medicine and Surgery and Center of Molecular Medicine, Karolinska Institutet Stockholm, Sweden ; Department of Clinical Genetics, Karolinska University Hospital Stockholm, Sweden ; Science for Life Laboratory, Karolinska Institutet Science Park Stockholm, Sweden
| | - Wolfgang Hofmeister
- Department of Molecular Medicine and Surgery and Center of Molecular Medicine, Karolinska Institutet Stockholm, Sweden
| | - Anna Lindstrand
- Department of Molecular Medicine and Surgery and Center of Molecular Medicine, Karolinska Institutet Stockholm, Sweden ; Department of Clinical Genetics, Karolinska University Hospital Stockholm, Sweden
| | - Nadav Ahituv
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco San Francisco ; Institute for Human Genetics, University of California San Francisco San Francisco
| | - Julia Vandermeer
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco San Francisco ; Institute for Human Genetics, University of California San Francisco San Francisco
| | - Anders Amilon
- Department of Hand Surgery, Örebro University Hospital Örebro, Sweden
| | - Göran Annerén
- Department of Immunology Genetics and Pathology Science for Life Laboratory, Uppsala University Uppsala, Sweden
| | - Marianne Arner
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet Stockholm, Sweden ; Department of Hand Surgery, Södersjukhuset Stockholm, Sweden
| | - Maria Pettersson
- Department of Molecular Medicine and Surgery and Center of Molecular Medicine, Karolinska Institutet Stockholm, Sweden
| | - Nina Jäntti
- Department of Molecular Medicine and Surgery and Center of Molecular Medicine, Karolinska Institutet Stockholm, Sweden
| | - Hans-Eric Rosberg
- Department of Clinical Sciences Malmö Section of Hand Surgery, Lund University Malmö, Sweden ; Department of Hand Surgery, Skåne University Hospital Malmö, Sweden
| | | | - Agneta Nordenskjöld
- Department of Women's and Children's Health and Center of Molecular Medicine, Karolinska Institutet Stockholm, Sweden ; Unit of Paediatric Surgery Astrid Lindgren Children's Hospital, Karolinska University Hospital Stockholm, Sweden
| | - Outi Mäkitie
- Department of Molecular Medicine and Surgery and Center of Molecular Medicine, Karolinska Institutet Stockholm, Sweden ; Department of Clinical Genetics, Karolinska University Hospital Stockholm, Sweden ; Folkhälsan Institute of Genetics Helsinki, Finland
| | - Giedre Grigelioniene
- Department of Molecular Medicine and Surgery and Center of Molecular Medicine, Karolinska Institutet Stockholm, Sweden ; Department of Clinical Genetics, Karolinska University Hospital Stockholm, Sweden
| | - Ann Nordgren
- Department of Molecular Medicine and Surgery and Center of Molecular Medicine, Karolinska Institutet Stockholm, Sweden ; Department of Clinical Genetics, Karolinska University Hospital Stockholm, Sweden
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18
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Jamsheer A, Śmigiel R, Jakubiak A, Zemojtel T, Socha M, Robinson PN, Mundlos S. Further evidence forFGF16truncating mutations as the cause of X-linked recessive fusion of metacarpals 4 / 5. ACTA ACUST UNITED AC 2014; 100:314-8. [DOI: 10.1002/bdra.23239] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 02/17/2014] [Accepted: 02/18/2014] [Indexed: 11/08/2022]
Affiliation(s)
- Aleksander Jamsheer
- Department of Medical Genetics; Poznan University of Medical Sciences; Poznan Poland
- NZOZ Center for Medical Genetics GENESIS; Poznan Poland
| | - Robert Śmigiel
- Department of Pediatrics and Rare Disorders; Wroclaw Medical University; Wroclaw Poland
| | | | - Tomasz Zemojtel
- Institute of Bioorganic Chemistry, Polish Academy of Sciences; Poznan Poland
- Institute for Medical Genetics and Human Genetics, Charité-Universitätsmedizin Berlin; Berlin Germany
| | - Magdalena Socha
- Department of Medical Genetics; Poznan University of Medical Sciences; Poznan Poland
| | - Peter N. Robinson
- Institute for Medical Genetics and Human Genetics, Charité-Universitätsmedizin Berlin; Berlin Germany
| | - Stefan Mundlos
- Institute for Medical Genetics and Human Genetics, Charité-Universitätsmedizin Berlin; Berlin Germany
- Max Planck Institute for Molecular Genetics; Berlin Germany
- Berlin-Brandenburg Center for Regenerative Therapies (BCRT); Charité-Universitätsmedizin Berlin; Berlin Germany
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19
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Chromosome X-wide association study identifies Loci for fasting insulin and height and evidence for incomplete dosage compensation. PLoS Genet 2014; 10:e1004127. [PMID: 24516404 PMCID: PMC3916240 DOI: 10.1371/journal.pgen.1004127] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 12/05/2013] [Indexed: 11/19/2022] Open
Abstract
The X chromosome (chrX) represents one potential source for the “missing heritability” for complex phenotypes, which thus far has remained underanalyzed in genome-wide association studies (GWAS). Here we demonstrate the benefits of including chrX in GWAS by assessing the contribution of 404,862 chrX SNPs to levels of twelve commonly studied cardiometabolic and anthropometric traits in 19,697 Finnish and Swedish individuals with replication data on 5,032 additional Finns. By using a linear mixed model, we estimate that on average 2.6% of the additive genetic variance in these twelve traits is attributable to chrX, this being in proportion to the number of SNPs in the chromosome. In a chrX-wide association analysis, we identify three novel loci: two for height (rs182838724 near FGF16/ATRX/MAGT1, joint P-value = 2.71×10−9, and rs1751138 near ITM2A, P-value = 3.03×10−10) and one for fasting insulin (rs139163435 in Xq23, P-value = 5.18×10−9). Further, we find that effect sizes for variants near ITM2A, a gene implicated in cartilage development, show evidence for a lack of dosage compensation. This observation is further supported by a sex-difference in ITM2A expression in whole blood (P-value = 0.00251), and is also in agreement with a previous report showing ITM2A escapes from X chromosome inactivation (XCI) in the majority of women. Hence, our results show one of the first links between phenotypic variation in a population sample and an XCI-escaping locus and pinpoint ITM2A as a potential contributor to the sexual dimorphism in height. In conclusion, our study provides a clear motivation for including chrX in large-scale genetic studies of complex diseases and traits. The X chromosome (chrX) analyses have often been neglected in large-scale genome-wide association studies. Given that chrX contains a considerable proportion of DNA, we wanted to examine how the variation in the chromosome contributes to commonly studied phenotypes. To this end, we studied the associations of over 400,000 chrX variants with twelve complex phenotypes, such as height, in almost 25,000 Northern European individuals. Demonstrating the value of assessing chrX associations, we found that as a whole the variation in the chromosome influences the levels of many of these phenotypes and further identified three new genomic regions where the variants associate with height or fasting insulin levels. In one of these three associated regions, the region near ITM2A, we observed that there is a sex difference in the genetic effects on height in a manner consistent with a lack of dosage compensation in this locus. Further supporting this observation, ITM2A has been shown to be among those chrX genes where the X chromosome inactivation is incomplete. Identifying phenotype associations in regions like this where chrX allele dosages are not balanced between men and women can be particularly valuable in helping us to understand why some characteristics differ between sexes.
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