Analysis of Gene Polymorphism in Skeletal Class-III Malocclusion Due to Mandibular Prognathism.

 Mandibular prognathism (MP) is a craniofacial deformity resulting from the combined effects of environmental and genetic factors. Although various linkage and genome-wide association studies for mandibular prognathism have identified multiple strongly associated regions and genes, the causal genes and variants responsible for the deformity remained ambiguous.  This research work was aimed to study the association between polymorphism rs10850110 of the gene and skeletal class-III malocclusion in our local population.  Thirty patients with skeletal class III due to mandibular prognathism in the study group and 30 patients with skeletal class I in the control group were selected for this study. These patients were from both sexes and above age 10 years. Based on the cephalometric values, patients were categorized into study and control groups. SNB (angle between sella, nasion and point B at nasion) greater than 82 degrees with an ANB (angle between point A, nasion and point B at nasion) of less than 0 degrees in the study group and ANB (angle between point A, nasion and point B at nasion) of 2 to 4 degrees in the control group were categorized. The polymorphism (rs10850110) of the gene was genotyped using polymerase chain reaction and restriction fragment length polymorphism. Associations were tested with SNP exact test using SNPstats software.  The single-nucleotide polymorphism rs10850110 showed a statistically significant association with mandibular prognathism. The G allele of marker rs10850110 (5' of myosin1H ) was overrepresented when compared with the "A" allele in mandibular prognathism cases (  < 0.0001), and this was very significant.  These results suggest that the rs10850110 polymorphism of the gene is associated with an increased risk for mandibular prognathism.