About this Research Topic
Each year, ~130 million babies are born worldwide. Approximately 4% of these babies – 5 million new births – will present with a structural or functional defect that substantially impairs their start to life. Congenital malformations that affect the skull, face and/or jaws (commonly referred to as craniofacial defects) will be present in approximately 3.5-4 million of these newborn babies, and these defects range from relatively minor anomalies that subtly affect facial development to significant malformations of the brain and skull that are incompatible with life.
The aetiology of craniofacial defects can be broadly ascribed to two primary causative factors – DNA mutations in genes that are critical for the correct establishment of the craniofacial complex and environmental factors that lead to a toxic microenvironment that impairs embryonic development.
Furthermore, exposure to environmental insult in genetically susceptible or compromised individuals, so-called “Gene-Environment Interactions“ [GxE], constitute a further high-risk population for the development of congenital craniofacial anomalies. While many structural malformations can be corrected post-natally through surgery, as such healthcare options are lacking in many parts of the world, novel strategies to lessens the healthcare burden of congenital defects is urgently needed .
Although many critical genes – such as TCOF1, Tbx22, Osr2, Grhl3, IRF6, FGFR2 and others – have been identified from both animal experimentation and human Genome-Wide Association Studies (GWAS) to be critical in patterning the craniofacial skeleton in vertebrates, the identities of many other genes and non-coding regulatory elements (such as enhancers and microRNAs) that subtly affect the formation of the vertebrate head remain unknown. Similarly, many environmental toxins that impinge on embryonic development – such as alcohol, cigarette smoke, bacterial infection and vitamin deficiency – are also well- characterized, although the influence of many further toxins or nutrient deficiencies is yet to be explored. In fact, currently the aetiology of ~50% of all birth defects is unknown, yet is almost certain to involve the interaction between genetic susceptibility and environmental insult.
Epidemiological data indicates that the incidence of craniofacial defects in developing countries is in some cases twice as high as in developed countries, indicating that environmental exposure to (known) toxins is still a substantial issue in these countries. However, these data also give hope that craniofacial defects in developed countries may be reduced even further through a greater understanding of environmental insult during pregnancy.
Understanding the genetic, environmental and GxE causes of craniofacial malformations therefore, forms one of the most promising therapeutic avenues to either preventing, or substantially reducing, both the incidence and severity of craniofacial anomalies in at-risk populations.
**Preference will be given to articles regarding analyses that define novel Gene-Environment Interaction relationships in craniofacial development.
• The identification of novel genes and/or genetic pathways that regulate the formation of the craniofacial skeleton.
• Defined epigenetic and non-coding (genomic) factors that influence craniofacial morphology.
• Statistical and modelling approaches to understanding etiology of craniofacial defects.
• Novel environmental factors that contribute to craniofacial anomalies.
• Cellular and tissue interactions in craniofacial development and malformations.
• GWAS or epidemiological analyses that also comprise a cellular or animal model of genes/factors of interest
• Human genetic variation that influences craniofacial morphogenesis/is associated with craniofacial defects.
• New approaches/new animal models to identifying factors that influence craniofacial development.
Keywords: Gene-Environment Interactions, Craniofacial Malformations, Birth Defects, Embryogenesis, Genetic Mutations
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