Comparative cephalometric analysis in patients with X-chromosome aneuploidy

Area of Science:

• Genetics
• Craniofacial Biology
• Endocrinology

Background:

• Sex chromosome aneuploidies, including Turner's syndrome (45 XO) and Klinefelter's syndrome (47 XXY), are known to affect various physiological processes.
• The specific impact of these conditions on craniofacial development and morphology remains an area of active investigation.

Purpose of the Study:

• To investigate the influence of abnormal sex chromosome constitutions on cranial growth, shape, and the position of craniofacial structures.
• To elucidate the differential effects of X chromosome absence versus duplication on craniofacial morphology.

Main Methods:

• Analysis of cranial growth, shape, and craniofacial structure positioning in individuals with documented sex chromosome abnormalities.
• Comparison of craniofacial features between individuals with Turner's syndrome and Klinefelter's syndrome.

Main Results:

• Reduced cranial growth was observed in both women with Turner's syndrome (45 XO) and men with Klinefelter's syndrome (47 XXY).
• Lack of or an extra X chromosome demonstrated opposing effects on cranial-base flexion, jaw displacement, and maxillary/mandibular inclination.
• An extra X chromosome was associated with deviations in sagittal jaw relation, while X chromosome absence influenced mandibular shape.

Conclusions:

• Abnormal sex chromosome constitutions significantly influence craniofacial development and morphology.
• Specific effects on cranial base, jaw relationship, and mandibular shape are linked to the presence or absence of an additional X chromosome.