A family study of craniofacial dimensions in the Burlington Growth Centre sample.

Lateral cephalometric radiographs were used to study the similarities in craniofacial dimensions between members of 147 families. Standard product-moment and intraclass correlation coefficients were calculated for a selected series of measurements to compare parents to offspring and sibs to sibs. To assess further the use of the parents' records in predicting a child's craniofacial features, r2 values were calculated and multiple regression analyses were performed for the various pairings of related individuals. Results show a high level of significant correlations between first-degree relatives which are compatible with a polygenic theory of inheritance. These data give no evidence of added effects of autosomal dominance and sex-linkage. As might be expected, the use of multiple measurements from both parents gives the best results when one is attempting to predict a child's craniofacial dimensions. This suggests that information from the parents and siblings of a patient can be quite useful in clinical orthodontic treatment.