Craniofacial Skeletal Dysplasia of Opposite-sex Dizygotic Twins

• Main Authors: Szu-Ting Chou, Yu-Chuan Tseng, Chin-Yun Pan, Jenny Zwei-Chieng Chang, Hong-Po Chang
• Format: Article
• Language: English
• Published: Elsevier 2011-05-01
• Series: Journal of the Formosan Medical Association
• Subjects: dizygotic twins; malocclusion; opposite-sex twins; orthodontic treatment; skeletal dysplasia
• Online Access: http://www.sciencedirect.com/science/article/pii/S092966461160051X

Craniofacial skeletal dysplasia can lead to different skeletal malocclusions. Both environmental factors and heredity contribute to the formation of malocclusions. There are strong familial tendencies in the development of Angle's Class II and III malocclusions. Cases such as opposite-typed (Class II and III) malocclusions with skeletal and dentoalveolar discordance in siblings or dizygotic (DZ) twins have seldom been reported. We describe the rare case of a pair of opposite-sex DZ twins with completely different skeletal malocclusions, and discuss the clinical considerations for treatment. The patients were twins aged 13 years and 4 months. The girl had mandibular prognathism and a Class III dentoskeletal relationship, whereas the boy had skeletal Class II with mandibular retrusion. Several morphological traits have been implicated with hormonal effect. However, there was no evidence of whether the masculinization effect had any impact on jaw size in the female fetus or whether this effect lasted into adolescence. We suggest that, although DZ twins share the same growth environment, genetic or other unknown extrinsic factors can result in discordance of characteristics of the craniofacial skeleton, dentition, and occlusion.