Embryologie de la face et dysplasies otomandibulaires

Abstract

RÉSUMÉ -Les dysplasies otomandibulaires regroupent l'ensemble des malformations congénitales qui affectent l'oreille et les mâchoires. La compréhension préalable du développement normal de l'embryon facilite l'approche clinique et thérapeutique des pathologies malformatives. Le développement des structures cranio-faciales met en jeu des mécanismes dont nous commençons à appréhender la complexité. Dans cette revue de la littérature, l'embryologie de la région otomandibulaire est rappelée. À la lumière des travaux récents de génétique et d'embryologie expérimentale, une approche clinique de la dysostose mandibulo-faciale est envisagée et une mise à jour des hypothèses pathogéniques est proposée.MOTS CLÉS -Dysostose mandibulo-faciale / Dysplasie otomandibulaire / Face / Embryologie / Treacher-Collins ABSTRACT -Otomandibular dysplasias encompass a broad range of congenital malformations (hemifacial microsomia, mandibulofacial dysostosis) affecting both jaw and ear apparatus. Deciphering the mechanisms of normal embryonic development is a prerequisite for optimal clinical management of those malformations. The development of craniofacial structures is a multi-step process, which involves many developmental events ranging from the migration of neural crest cells from the neural primordium, the molecular interactions that coordinate outgrowth and patterning of the facial primordia, to the fine tuning of the skeletal components. Our knowledge concerning craniofacial development has been gain through experiments carried out in animal developmental models; cell tracing strategies and functional analyses have contributed to significantly increment our understanding of human otomandibular dysplasias. In this review, we discuss classical and recent aspects of otomandibular development. Current proposals for pathogenesis are reviewed and a clinical approach for mandibulofacial dysostosis is proposed.

Bilateral elongated mandibular coronoid process in an Anatolian skull

“…In the fourth week of gestation, proliferation of neural crest cells that migrate into the branchial arches produce the mandibular prominences. The neural crest cells come from the region of the hindbrain and give rise to cartilage, bone and ligaments in the facial and oral regions [ 18 ].…”