The Developmental Interrelation Between the Nervous System and Craniofacial Complex as Evidenced from Craniofacial Malformations

The craniofacial complex develops during the first trimester of pregnancy, but its final shaping, which is mainly dependent on genetic factors, extends into the second and third trimesters. It is intimately connected with the development of the brain because the numerous signals which control craniofacial development originate in the brain and vice versa. As a result, malformations of one organ may affect the development of the other. Craniofacial anomalies are either isolated, resulting from abnormal development of the first two embryonic pharyngeal arches, or part of multiple malformation syndromes affecting many other organs. They may stem from gene mutations, chromosomal aberrations, or environmental causes induced by teratogens. The craniofacial morphologic changes are not only cosmetic as they may often interfere with important functions such as chewing, swallowing, and respiration and/or cause hearing or visual impairment. We discussed only a small number of craniofacial malformations and their diagnosis and treatment. Following a brief description of the craniofacial development, we discussed oral clefts, craniofacial microsomia, and teratogens that may affect craniofacial development resulting in different malformations and the genetically determined craniosynostosis syndromes. The understanding of these malformations is important in medicine and in dentistry as the approach for diagnosis and treatment is generally multidisciplinary.