In the 15-year interval separating the first edition of The Neural Crest from the present book, our understanding of the ontogeny of this structure has progressed considerably. New derivatives of the neural crest have not been discovered but truly novel perspectives have illuminated the field. Considering the list of neural crest derivatives summarized in Table 8.1, one can only be overwhelmed by the impressive diversification of phenotypes arising from this discrete and transient embryonic structure and by its paramount participation to the vertebrate organism. By means of the PNS, the neural crest provides the body with an efficient communication system with the outside world, and within the organism itself. By means of pigment cells, the neural crest provides protection from UV light and a means of undergoing adaptative color changes. Furthermore, the neural crest has accommodated the large increase in brain size which took place during vertebrate evolution by providing it with the skull. Thus, it appears to be a highly adaptative structure and, as it is absent from their chordate ancestors, the neural crest can be considered as a “spectacular invention” of vertebrates as pointed out by Gans in 1987.

One is also incited to seek for common denominators between the highly diversified neural crest derivatives. Such a line of thinking is stimulated by the existence of congenital anomalies in which multisystem neural crest defects (neuronal and pigmentary, neuronal and craniofacial, neuronal and endocrine, etc.) are found to be associated. Molecules mutated in specific neurocristopathies have begun to be elucidated, and provide precious tools to tackle these links.