[A cephalometric study on the similarity of craniofacial morphology between children and their parents]

This study was performed to estimate genetic influences on craniofacial form and to obtain a method of analysing the characteristics in a child as well as the individual growth prediction in each child. Posteroanterior and lateral cephalographs were used to estimate the morphological similarities of craniofacial form between 150 children and their parents. Subjects consisted of 38 boys and 112 girls who were estimated to mature according to the bone maturity index (B.M.I.) on the hand radiographs and who were older than 13 years chosen from among 3,500 orthodontic patients registered at the University Hospital associated with the Faculty of Dentistry, Kyushu University. The correlation analysis in family, estimation of the sexual linkage, the multi-regression analysis and estimation of the heritability of craniofacial characters were computed. The differences in correlations were also tested between prepuberty and postpuberty craniofacial forms in another 100 children with orthodontic treatment. The results are as follows: 1. The craniofacial form of children was highly correlated with that of their parents. 2. The genetic effects of determining the craniofacial form of offspring by the father were equivalent to those by the mother, but daughters were more affected by parents than were sons. 3. The proportions of multi-regression functions ranged from 3.7 to 34.0 percent. These values are too low to predict the growth of a child. 4. The calculated heritabilities on craniofacial form were from 0.286 to 0.962, with the majority being more than 0.600. 5. The coefficients of correlation between the children and their parents increased with growth, regardless of their orthodontic treatment.