Phenotypic characterization of Class III patients.

OBJECTIVE

The objective of this study is to characterize the convergences of dentofacial form of skeletal Class III malocclusion in individuals to test the fundamental hypothesis that there are distinct subtypes of Class III malocclusion.

MATERIALS AND METHODS

A detailed phenotypic characterization was performed on a retrospective cohort of 309 subjects using cluster and principal component analyses on 67 cephalometric variables.

RESULTS

The results indicated that there are five clusters representing distinct subphenotypes. The principal component analysis suggested that the groupings of variables reflect anteroposterior and vertical dimensions rather than specific craniofacial structures. This may ultimately suggest that different genes are involved in controlling dimension vs structures.

CONCLUSIONS

Our phenotypic dissection of Class III malocclusion established distinct subtypes in a large sample of patients and will ultimately provide the basis for future familial studies to identify a causative gene.