editorial comment by series editor: re: article by carstens m: “neural tube programming and...

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WHAT’S NEW IN NEUROEMBRYOLOGY? Editorial comment by series editor Re: article by Carstens M: “Neural tube programming and craniofacial cleft formation” This article by Dr Michael Carstens is unique in the paediatric neurology literature. Why should a plastic/craniofacial surgeon be writing for an audience of paediatric neurologists? The originality of his contribution is that he links the embryology of extraneural structures of the face and head with development of the neural tube and demonstrates that neural ontogenesis is indeed the determining factor for a wide array of non-neural structures of bone, cartilage and soft tissues. Though the concept of neural crest migration to form extra- neural structures is not new, the perspective here presented is novel: a head and face embryologist presents a neuroanatomical explanation for the head and face, including structures of branchial pouch derivation, bones of the cranium, cartilages and ‘soft tissues’. This effort represents the best of specialists with different training and perspective to communicate about development to reveal common truths. He is able to reverse the order of DeMyer’s famous statement in 1964, The face predicts the brain, a clinical observation, to The brain predicts the face, an insight into a mechanism of ontogeny. This is the first of a series of papers in the EJPN by Dr Carstens to explain early embryological events and provide a rational understanding of, for example, the medial to lateral organization of motor neurons in the spinal cord and brainstem. His data and interpretations amplify the concept of gradients of genetic expression in the axes of the normal neural tube and in malformations, previously presented in this series as a revised classification of dysgeneses that integrates morphogenesis and genetic programming (Sarnat HB, Flores-Sarnat L. Eur J Paediatr Neurol 2001;5:57 – 64). Later papers in this series will address very specific issues dear to the hearts of clinical geneticists and dysmor- phologists, such as hyper- and hypo-telorism, the ontogenesis of low-set and malformed ears, and malpositioning of other facial structures. For paediatric neurologists, these features are more important than the mere clinical recognition of defined genetic syndromes or chromosomopathies; they emanate from disturbances in the rostral neural tube and often alter the function of the brain at maturity. The importance of the study of craniofa- cial clefts is that each cleft, indicating the absence of neural crest bone formation, is a marker of the site and timing of the neural crest migration from specific individual segments of the brain. This series thus initiates a communication between embryolo- gists, craniofacial surgeons and paediatric neurol- ogists who share a common goal of understanding developmental malformations without restricting the focus to a single tissue, even if that tissue is the brain. For neurologists, the neural induction of other tissues is as important as the ontogeny of the nervous system itself. What is the single aspect that most distinguishes paediatric from adult neurologists? The manage- ment of seizures, the diagnosis of myopathies, the treatment of CNS infections and the rehabilitation of patients after stroke or other brain damage share similarities in children and adults, though some important differences also occur. The spectrum of metabolic and genetic diseases of the nervous system is different between children and adults, but there is considerable overlap in many. The aspect of paediatric neurology that is unique and absent in adult neurology is development. An understanding of embryology is primordial to the meaning of development, and paediatric neurol- ogists often are less well versed in morphogenesis than they should be. Embryology is not just for the laboratory investigator. This series has a general goal of enhancing an important aspect in the education of paediatric neurologists, but it requires 1090-3798/$ - see front matter Q 2004 Published by Elsevier Ltd on behalf of European Paediatric Neurology Society. doi:10.1016/j.ejpn.2004.04.002 European Journal of Paediatric Neurology (2004) 8, 179–180 www.elsevier.com/locate/ejpn

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Page 1: Editorial comment by series editor: Re: article by Carstens M: “Neural tube programming and craniofacial cleft formation”

WHAT’S NEW IN NEUROEMBRYOLOGY?

Editorial comment by series editor

Re: article by Carstens M: “Neural tube programmingand craniofacial cleft formation”

This article by Dr Michael Carstens is unique in thepaediatric neurology literature. Why should aplastic/craniofacial surgeon be writing for anaudience of paediatric neurologists? The originalityof his contribution is that he links the embryology ofextraneural structures of the face and head withdevelopment of the neural tube and demonstratesthat neural ontogenesis is indeed the determiningfactor for a wide array of non-neural structures ofbone, cartilage and soft tissues. Though theconcept of neural crest migration to form extra-neural structures is not new, the perspective herepresented is novel: a head and face embryologistpresents a neuroanatomical explanation for thehead and face, including structures of branchialpouch derivation, bones of the cranium, cartilagesand ‘soft tissues’. This effort represents the best ofspecialists with different training and perspectiveto communicate about development to revealcommon truths. He is able to reverse the order ofDeMyer’s famous statement in 1964, The facepredicts the brain, a clinical observation, to Thebrain predicts the face, an insight into a mechanismof ontogeny.

This is the first of a series of papers in the EJPN byDr Carstens to explain early embryological eventsand provide a rational understanding of, forexample, the medial to lateral organization ofmotor neurons in the spinal cord and brainstem.His data and interpretations amplify the concept ofgradients of genetic expression in the axes of thenormal neural tube and in malformations, previouslypresented in this series as a revised classification ofdysgeneses that integrates morphogenesis andgenetic programming (Sarnat HB, Flores-SarnatL. Eur J Paediatr Neurol 2001;5:57–64). Later papersin this series will address very specific issues dearto the hearts of clinical geneticists and dysmor-phologists, such as hyper- and hypo-telorism,

the ontogenesis of low-set and malformed ears,and malpositioning of other facial structures. Forpaediatric neurologists, these features are moreimportant than the mere clinical recognition ofdefined genetic syndromes or chromosomopathies;they emanate from disturbances in the rostral neuraltube and often alter the function of the brain atmaturity. The importance of the study of craniofa-cial clefts is that each cleft, indicating the absenceof neural crest bone formation, is a marker of thesite and timing of the neural crest migration fromspecific individual segments of the brain. This seriesthus initiates a communication between embryolo-gists, craniofacial surgeons and paediatric neurol-ogists who share a common goal of understandingdevelopmental malformations without restrictingthe focus to a single tissue, even if that tissue is thebrain. For neurologists, the neural induction of othertissues is as important as the ontogeny of the nervoussystem itself.

What is the single aspect that most distinguishespaediatric from adult neurologists? The manage-ment of seizures, the diagnosis of myopathies, thetreatment of CNS infections and the rehabilitation ofpatients after stroke or other brain damage sharesimilarities in children and adults, though someimportant differences also occur. The spectrum ofmetabolic and genetic diseases of the nervoussystem is different between children and adults,but there is considerable overlap in many. Theaspect of paediatric neurology that is unique andabsent in adult neurology is development. Anunderstanding of embryology is primordial to themeaning of development, and paediatric neurol-ogists often are less well versed in morphogenesisthan they should be. Embryology is not just for thelaboratory investigator. This series has a generalgoal of enhancing an important aspect in theeducation of paediatric neurologists, but it requires

1090-3798/$ - see front matter Q 2004 Published by Elsevier Ltd on behalf of European Paediatric Neurology Society.doi:10.1016/j.ejpn.2004.04.002

European Journal of Paediatric Neurology (2004) 8, 179–180

www.elsevier.com/locate/ejpn

Page 2: Editorial comment by series editor: Re: article by Carstens M: “Neural tube programming and craniofacial cleft formation”

active, not passive, participation by carefully read-ing and really trying to comprehend fundamentalconcepts of ontogenesis, that are so well presentedin this review by Dr Carstens. As neurologists, wemust broaden our perspective to include not only theontogenesis of the nervous system itself, but thenon-neural tissues induced by it or with which itinteracts during development.

Harvey B. SarnatAlberta Children’s Hospital,

Division of Paediatric Neurology/Neuropathology,1820 Richmond Road SW,

Calgary, Alberta T2T 5C7,Canada

Tel.: þ403-943-7816; fax: þ403-943-7649E-mail : [email protected]

H.B. Sarnat180