Craniofacial morphology is a complex physical trait determined by genetic and environmental factors, and the relative interactions between these factors lead to varying craniofacial phenotypes. 1 From the orthodontic viewpoint, various craniofacial phenotypes refer to the relative sagittal and vertical relationships between the cranial base, maxilla and mandible. 2 Among the diverse craniofacial phenotypes, the mandibular prognathism (MP) is defined as a sagittal discrepancy on the skeletal structure in which the mandible is positioned more anteriorly relative to the maxilla regardless of the vertical type of the mandible. MP also results from the interactions between environmental and genetic factors. 3,4 However, to date, most studies have focused on the genetic factors associated with mandibular overgrowth. [5][6][7][8]