Talk:Musculoskeletal System - Limb Abnormalities
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Cite this page: Hill, M.A. (2019, July 18) Embryology Musculoskeletal System - Limb Abnormalities. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Musculoskeletal_System_-_Limb_Abnormalities
A multidisciplinary review of triphalangeal thumb
J Hand Surg Eur Vol. 2018 Oct 14:1753193418803521. doi: 10.1177/1753193418803521. [Epub ahead of print]
Potuijt JWP1, Galjaard RH2, van der Spek PJ3,4, van Nieuwenhoven CA1, Ahituv N5,6, Oberg KC7, Hovius SER1.
Despite being a rare congenital limb anomaly, triphalangeal thumb is a subject of research in various scientific fields, providing new insights in clinical research and evolutionary biology. The findings of triphalangeal thumb can be predictive for other congenital anomalies as part of an underlying syndrome. Furthermore, triphalangeal thumb is still being used as a model in molecular genetics to study gene regulation by long-range regulatory elements. We present a review that summarizes a number of scientifically relevant topics that involve the triphalangeal thumb phenotype. Future initiatives involving multidisciplinary teams collaborating in the field of triphalangeal thumb research can lead to a better understanding of the pathogenesis and molecular mechanisms of this condition as well as other congenital upper limb anomalies. KEYWORDS: Triphalangeal thumb; congenital limb deformities; genetic enhancer elements; hedgehog protein; polydactyly PMID: 30318985 DOI: 10.1177/1753193418803521
Prenatal exposure to environmental factors and congenital limb defects
Birth Defects Res C Embryo Today. 2016 Sep;108(3):243-273. doi: 10.1002/bdrc.21140. Epub 2016 Oct 21.
Alexander PG1, Clark KL1, Tuan RS2.
Limb congenital defects afflict approximately 0.6:1000 live births. In addition to genetic factors, prenatal exposure to drugs and environmental toxicants, represents a major contributing factor to limb defects. Examples of well-recognized limb teratogenic agents include thalidomide, warfarin, valproic acid, misoprostol, and phenytoin. While the mechanism by which these agents cause dymorphogenesis is increasingly clear, prediction of the limb teratogenicity of many thousands of as yet uncharacterized environmental factors (pollutants) remains inexact. This is limited by the insufficiencies of currently available models. Specifically, in vivo approaches using guideline animal models have inherently deficient predictive power due to genomic and anatomic differences that complicate mechanistic comparisons. On the other hand, in vitro two-dimensional (2D) cell cultures, while accessible for cellular and molecular experimentation, do not reflect the three-dimensional (3D) morphogenetic events in vivo nor systemic influences. More robust and accessible models based on human cells that accurately replicate specific processes of embryonic limb development are needed to enhance limb teratogenesis prediction and to permit mechanistic analysis of the adverse outcome pathways. Recent advances in elucidating mechanisms of normal development will aid in the development of process-specific 3D cell cultures within specialized bioreactors to support multicellular microtissues or organoid constructs that will lead to increased understanding of cell functions, cell-to-cell signaling, pathway networks, and mechanisms of toxicity. The promise is prompting researchers to look to such 3D microphysiological systems to help sort out complex and often subtle interactions relevant to developmental malformations that would not be evident by standard 2D cell culture testing. Birth Defects Research (Part C) 108:243-273, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
KEYWORDS: anticonvulsant; cadmium; congenital limb defects; diabetes; environmental factors; ethanol; in vitro toxicity testing; limb development; microphysiological systems; misoprostol; organotypic culture models; phenytoin; prenatal exposure; teratogens; thalidomide; valproic acid; warfarin PMID 27768243 DOI: 10.1002/bdrc.21140
Role of Genetic Factors in the Pathogenesis of Radial Deficiencies in Humans
Curr Genomics. 2015 Aug;16(4):264-78. doi: 10.2174/1389202916666150528000412.
Elmakky A1, Stanghellini I1, Landi A2, Percesepe A1.
Radial deficiencies (RDs), defined as under/abnormal development or absence of any of the structures of the forearm, radial carpal bones and thumb, occur with a live birth incidence ranging from 1 out of 30,000 to 1 out 6,000 newborns and represent about one third/one fourth of all the congenital upper limb anomalies. About half of radial disorders have a mendelian cause and pattern of inheritance, whereas the remaining half appears sporadic with no known gene involved. In sporadic forms certain anomalies, such as thumb or radial hypoplasia, may occur either alone or in association with systemic conditions, like vertebral abnormalities or renal defects. All the cases with a mendelian inheritance are syndromic forms, which include cardiac defects (in Holt-Oram syndrome), bone marrow failure (in Fanconi anemia), platelet deficiency (in thrombocytopenia-absent-radius syndrome), ocular motility impairment (in Okihiro syndrome). The genetics of radial deficiencies is complex, characterized by genetic heterogeneity and high inter- and intra-familial clinical variability: this review will analyze the etiopathogenesis and the genotype/phenotype correlations of the main radial deficiency disorders in humans. KEYWORDS: Congenital upper limb anomalies; Radial deficiency; Thumb hypoplasia PMID 26962299
Sirenomelia phenotype in bmp7;shh compound mutants: a novel experimental model for studies of caudal body malformations
PLoS One. 2012;7(9):e44962. doi: 10.1371/journal.pone.0044962. Epub 2012 Sep 17.
Garrido-Allepuz C, González-Lamuño D, Ros MA. Source Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), CSIC-SODERCAN-Universidad de Cantabria, Santander, Spain.
Sirenomelia is a severe congenital malformation of the lower body characterized by the fusion of the legs into a single lower limb. This striking external phenotype consistently associates severe visceral abnormalities, most commonly of the kidneys, intestine, and genitalia that generally make the condition lethal. Although the causes of sirenomelia remain unknown, clinical studies have yielded two major hypotheses: i) a primary defect in the generation of caudal mesoderm, ii) a primary vascular defect that leaves the caudal part of the embryo hypoperfused. Interestingly, Sirenomelia has been shown to have a genetic basis in mice, and although it has been considered a sporadic condition in humans, recently some possible familial cases have been reported. Here, we report that the removal of one or both functional alleles of Shh from the Bmp7-null background leads to a sirenomelia phenotype that faithfully replicates the constellation of external and internal malformations, typical of the human condition. These mutants represent an invaluable model in which we have analyzed the pathogenesis of sirenomelia. We show that the signaling defect predominantly impacts the morphogenesis of the hindgut and the development of the caudal end of the dorsal aortas. The deficient formation of ventral midline structures, including the interlimb mesoderm caudal to the umbilicus, leads to the approximation and merging of the hindlimb fields. Our study provides new insights for the understanding of the mechanisms resulting in caudal body malformations, including sirenomelia.
Thumb duplication: concepts and techniques
Clin Orthop Surg. 2012 Mar;4(1):1-17. Epub 2012 Feb 20.
Tonkin MA. Source Department of Hand Surgery and Peripheral Nerve Surgery, University of Sydney, Royal North Shore Hospital, St. Leonards, Australia. firstname.lastname@example.org
Within the Oberg, Manske, Tonkin (OMT) classification, thumb duplications are a failure of formation and/or differentiation affecting the radial-ulnar axis of the hand plate. The Wassel description of seven types of thumb duplication provides a good structure from which an approach to management is based. The aim of surgical reconstruction is to obtain a stable, mobile thumb of adequate size and appropriate shape. The most common form of reconstruction is removal of the lesser digit and reconstruction of the dominant digit. Surgical techniques address the problems of deviation, instability and lack of size. The disadvantages of the Bilhaut-Cloquet procedure, these being joint stiffness and a nail ridge, may be lesser concerns when reconstruction of one digit will not create a satisfactory thumb of adequate mobility, stability, alignment and size. Complicated problems of triphalangism, triplication, ulnar dimelia and the rare circumstance in which neither of the duplicated thumbs may be adequately reconstructed present specific challenges which demand alternative techniques.
A clinical and experimental overview of sirenomelia: insight into the mechanisms of congenital limb malformations
Dis Model Mech. 2011 May;4(3):289-99. Epub 2011 Apr 18.
Garrido-Allepuz C, Haro E, González-Lamuño D, Martínez-Frías ML, Bertocchini F, Ros MA. Source Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-CSIC-SODERCAN, C. Herrera Oria s/n, 39011 Santander, Spain.
Sirenomelia, also known as sirenomelia sequence, is a severe malformation of the lower body characterized by fusion of the legs and a variable combination of visceral abnormalities. The causes of this malformation remain unknown, although the discovery that it can have a genetic basis in mice represents an important step towards the understanding of its pathogenesis. Sirenomelia occurs in mice lacking Cyp26a1, an enzyme that degrades retinoic acid (RA), and in mice that develop with reduced bone morphogenetic protein (Bmp) signaling in the caudal embryonic region. The phenotypes of these mutant mice suggest that sirenomelia in humans is associated with an excess of RA signaling and a deficit in Bmp signaling in the caudal body. Clinical studies of sirenomelia have given rise to two main pathogenic hypotheses. The first hypothesis, based on the aberrant abdominal and umbilical vascular pattern of affected individuals, postulates a primary vascular defect that leaves the caudal part of the embryo hypoperfused. The second hypothesis, based on the overall malformation of the caudal body, postulates a primary defect in the generation of the mesoderm. This review gathers experimental and clinical information on sirenomelia together with the necessary background to understand how deviations from normal development of the caudal part of the embryo might lead to this multisystemic malformation.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial Share Alike License (http://creativecommons.org/licenses/by-nc-sa/3.0), which permits unrestricted non-commercial use, distribution and reproduction in any medium provided that the original work is properly cited and all further distributions of the work or adaptation are subject to the same Creative Commons License terms.
Developmental dysplasia of the hip
Lancet. 2007 May 5;369(9572):1541-52.
Dezateux C, Rosendahl K. Source Centre of Epidemiology for Child Health, Institute of Child Health, London, UK. email@example.com
In its severest form, developmental dysplasia of the hip is one of the most common congenital malformations. The pathophysiology and natural history of the range of morphological and clinical disorders that constitute developmental dysplasia of the hip are poorly understood. Neonatal screening programmes, based on clinical screening examinations, have been established for more than 40 years but their effectiveness remains controversial. Whereas systematic sonographic imaging of newborn and young infants has afforded insights into normal and abnormal hip development in early life, we do not clearly understand the longer-term outcomes of developmental hip dysplasia, its contribution to premature degenerative hip disorders in adult life, and the benefits and harms of newborn screening. High quality studies of the adult outcomes of developmental hip dysplasia and the childhood origins of early degenerative hip disease are needed, as are randomised trials to assess the effectiveness and safety of neonatal screening and early treatment.
There are several types of Brachydactyly:
|Type||OMIM||Gene||Locus (genetics)||Also known as/Description|
|Type A1, BDA1||112500||IHH BDA1B||5p13.3-p13.2, 2q33-q35||Brachydactyly type A1 or Farabee-type brachydactyly. BDA1 is an autosomal dominant inherited disease. Features include: Brachydactyly, Short or absent phalanges, Extra carpal bones, Hypoplastic or absent ulna and Short metacarpal bones.|
|Type A2, BDA2||112600||BMPR1B GDF5||20q11.2, 4q23-q24||Brachydactyly type A2, Brachymesophalangy II or Brachydactyly Mohr-Wriedt type. Type A2 is a very rare form of brachydactyly. The phalanges of the index fingers and second toes are shortened.|
|Type A3, BDA3||112700||Brachydactyly type A3, Brachymesophalangy V or Brachydactyly-Clinodactyly.|
|Type A4, BDA4||112800||Brachydactyly type A4, Brachymesophalangy II and V or Brachydactyly Temtamy type|
|Type A5, BDA5||112900||Brachydactyly type A5 nail dysplasia.|
|Type A6, BDA6||112910||Brachydactyly type A6 or Osebold-Remondini syndrome.|
|Type A7, BDA7||Brachydactyly type A7 or Brachydactyly Smorgasbord type.|
|Type B, BDB (or BDB1)||113000||ROR2||9q22||Brachydactyly type B.|
|Type C, BDC||113100||GDF5||20q11.2||Brachydactyly type C or Brachydactyly Haws type.|
|Type D, BDD||113200||HOXD13||2q31-q32||Brachydactyly type D.|
|Type E, BDE||113300||HOXD13||2q31-q32||Brachydactyly type E.|
|Type B and E||112440||ROR2 HOXD13||9q22, 2q31-q32||Brachydactyly types B and E combined, Ballard syndrome or Pitt-Williams brachydactyly.|
|Type A1B, BDA1B||607004||5p13.3-p13.2||Brachydactyly type A1, B.|
Morphogenesis and dysmorphogenesis of the appendicular skeleton
Shum L, Coleman CM, Hatakeyama Y, Tuan RS. Birth Defects Res C Embryo Today. 2003 May;69(2):102-22. Review.
Cartilage patterning and differentiation are prerequisites for skeletal development through endochondral ossification (EO). Multipotential mesenchymal cells undergo a complex process of cell fate determination to become chondroprogenitors and eventually differentiate into chondrocytes. These developmental processes require the orchestration of cell-cell and cell-matrix interactions. In this review, we present limb bud development as a model for cartilage patterning and differentiation. We summarize the molecular and cellular events and signaling pathways for axis patterning, cell condensation, cell fate determination, digit formation, interdigital apoptosis, EO, and joint formation. The interconnected nature of these pathways underscores the effects of genetic and teratogenic perturbations that result in skeletal birth defects. The topics reviewed also include limb dysmorphogenesis as a result of genetic disorders and environmental factors, including FGFR, GLI3, GDF5/CDMP1, Sox9, and Cbfa1 mutations, as well as thalidomide- and alcohol-induced malformations. Understanding the complex interactions involved in cartilage development and EO provides insight into mechanisms underlying the biology of normal cartilage, congenital disorders, and pathologic adult cartilage.