Comparative cephalometric analysis in patients with X-chromosome aneuploidy.

The influence of abnormal sex-chromosome constitution on cranial growth, shape and position of the craniofacial structures was analysed. Reduced cranial growth was found in women with Turner's syndrome (45 XO chromosome constitution) and in men with Klinefelter's syndrome (47 XXY chromosome constitution). Lack of or an extra X chromosome produced opposite effects on cranial-base flexion, jaw displacement and maxillary and mandibular inclination to the anterior cranial base. An extra X chromosome affected deviation in sagittal jaw relation while lack of an X chromosome influenced mandibular shape.