The craniofacial complex in 45,X/46,XX females

Fourteen Finnish 45,X/46,XX females were compared with population female an d male controls, and in addition, nine of them were compared with their fir st-degree female relatives. Linear and angular measurements were made from standardized lateral cephalograms of patients and normal population control s from the "Kvantti" study series. In both comparisons the results indicate d that craniofacial dimensions in 45,X/46,XX females were smaller than thos e in population female and male controls. The general metric pattern was si milar to that observed in relation to the tooth crowns of 45,X/46,XX female s. Several of their craniofacial proportions and plane angles differed from those of normal women: shorter anterior and posterior cranial bases and a Batter cranial-base angle, a sagittally shorter maxilla and a sagittally sh orter mandible with an enlarged ramus:corpus length ratio, posterior rotati on of the mandible and a tendency to bimaxillary retrusion. It is suggested that the reduction of X-chromosomal genetic material in 45,/46,XX females results in smaller craniofacial dimensions than in normal females, with sub stantial effects on dimensional ratios and especially plane angles of the c ranial base. (C) 1999 Elsevier Science Ltd. All rights reserved.