Point Mutations in Muscle Segment Homeobox 1 (MSX1) Gene in an Individual with Mandibular Retrognathia: A Case Report

Malocclusion is an orofacial anomaly that manifests in the form of misaligned dental arches. Mandibular retrognathia is a type of malocclusion, characterised by defective mandibular bone growth. Muscle Segment Homeobox (MSX) gene family, plays an essential role during embryonic development by coordinating processes that decide the patterning and morphogenesis of tissues. Expression of MSX1 and MSX2 genes in the maxilla, mandible and the mesenchymal cells of cephalic neural crest strongly suggest their role in craniofacial development. Here, point mutations (T8I, P11S and A68V) in the coding region of MSX1 gene in a 20-year-old male patient with severe mandibular retrognathia was reported. To date, there has been no report on the association of MSXgenes with mandibular anomalies. Evaluating, the significance of these novel mutations through functional studies in animal models will lead to a better understanding of the role of MSX genes in mandibular morphogenesis.

Developmentally Regulated Expression of Msx1, Msx2 and Fgfs in the Developing Mouse Cranial Base

Objective: To examine the expression pattern of the Fgf and Msx genes in cranial base development. Materials and Methods: To detect the expression of these genes, antisense riboprobes were synthesized by in vitro transcription. Radioactive in situ hybridization was performed on parasagittal sections of embryonic mouse heads. Results: Msx2 was observed in the underlying perichondrium at restricted stages. Msx1 was not observed in cranial base development. Fgf1 was localized in osteogenic cells from the time of ossification; Fgf10 was highly expressed in the occipital-vertebral joint during E13 to E14; Fgf2, Fgf7, and Fgf18 were localized in the perichondria; Fgf12 was transitorily expressed at early chondrocranium; Fgf9 was seen in the hypertrophic chondrocytes. Conclusions: The Fgf and Msx gene expression in the cranial base was different from that of other skeletons.