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