Growth-related changes in familial resemblance of maxillofacial morphology.

We investigated changes in resemblance between Japanese parents and their growing children with regard to maxillofacial morphology. Lateral roentgenographic cephalograms taken from 963 children (336 male and 627 female) over 6 years of age and their parents were used as samples. Based on the age of the children, there were six groups--I: 6-7 years of age; II: 8-9; III: 10-11; IV: 12-13; V: 14-15; and VI: over 16. Parent-offspring heritabilities (h2) were computed for 35 variables representing maxillofacial and dentoalveolar traits, and group comparisons were also made. The following results were obtained: (1) there were more significant heritabilities for maxillofacial variables than those for dentoalveolar ones; (2) in general, additive genetic effects were more prominent in controlling maxillofacial and dentoalveolar structure of on-growing children, with increasing age.