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Hemifacial microsomia: developmental consequence of perturbation of the auriculofacial cartilage model?
1School of Clinical Dentistry/Dental Surgery, Queen's University of Belfast, Northern Ireland.
Abstract:
The cause of hemifacial microsomia (HFM) is currently the subject of much investigation. Despite a large body of clinical and experimental data, little is certain other than the heterogeneity of this malformation complex. Here we suggest that some of the cases previously designated as being multifactorial in origin may be interpreted instead as resulting from a single-gene mutation, by applying a stochastic single-gene model. A variety of models of the pathogenesis of HFM have been described, including the proposal that local embryonic haemorrhage is a causal mechanism. More recently, it has been suggested that an interference in chondrogenesis is primarily responsible for the HFM phenotype. In this paper direct experimental evidence, based on surgical interference of mandibular development in the chick embryo, is applied in favour of the latter concept. In particular, asymmetrical perturbation of Meckel's cartilage has been shown to result in asymmetry of the mandible, and it is proposed that, irrespective of cause, the skeletal pathogenesis of HFM primarily involves the auriculofacial cartilage model.
Insights
Hemifacial microsomia (HFM) may result from single-gene mutations, not just multifactorial causes. Surgical interference in chick embryos suggests chondrogenesis disruption is key to HFM skeletal development.
Area of Science:
- Developmental Biology
- Genetics
- Craniofacial Anomalies
Background:
- Hemifacial microsomia (HFM) is a heterogeneous congenital condition with uncertain etiology.
- Existing models include embryonic hemorrhage and chondrogenesis interference.
Purpose of the Study:
- To investigate the pathogenesis of hemifacial microsomia (HFM).
- To propose a stochastic single-gene model for some HFM cases.
- To provide experimental evidence supporting chondrogenesis interference in HFM development.
Main Methods:
- Application of a stochastic single-gene model to HFM cases.
- Surgical perturbation of Meckel's cartilage in chick embryos.
Main Results:
- Some HFM cases may stem from single-gene mutations.
- Asymmetrical mandibular development observed following surgical interference.
- Evidence supports chondrogenesis interference as a primary mechanism in HFM.
Conclusions:
- The skeletal pathogenesis of HFM primarily involves the auriculofacial cartilage model.
- Disruption of chondrogenesis is a critical factor in HFM phenotype.
- A single-gene mutation model offers an alternative explanation for certain HFM presentations.