Upper cervical spine and craniofacial morphology in hypohidrotic ectodermal dysplasia

Aim: Morphological deviations in the upper cervical spine and craniofacial morphology in patients with X-linked hypohidrotic ectodermal dysplasia (XLHED) were compared to non-syndromic controls.

Methods: All children and adolescents with genetically verified XLHED, registered at the Resource Centres for Oral Health in Rare Diseases, who met the inclusion criteria, were included. The group thus comprised 15 XLHED patients (3 girls and 12 boys, aged 8-16 years, mean 11.2 years). The control group comprised 22 non-syndromic pre-orthodontic children (14 girls and 8 boys aged 9-16 years, mean 11.9 years) with agenesis of one tooth, neutral occlusion and normal craniofacial morphology. The craniofacial and upper spine morphology was analysed on lateral cephalograms by standard methods. Differences between XLHED patients and controls were tested and adjusted for age and gender by multiple regression analyses.

Results: Morphological deviations in the upper spine occur significantly more often in XLHED patients compared to controls (60 vs. 9.1%; p < 0.01). The cranial base angle (n-s-ar, p < 0.05), sagittal jaw relationship (ss-n-pg, p < 0.001), maxillary inclination (NSL/NL, p < 0.001) and mandibular inclination (NSL/ML, p < 0.01) were significantly smaller in XLHED patients compared to controls. The mandibular prognathia (s-n-pg) was significantly larger in XLHED patients compared to controls (p < 0.05).

Conclusions: The upper spine and the craniofacial morphology were different in XLHED patients compared to controls. The results of this study may contribute to a further understanding of the craniofacial and spinal phenotypic spectrum in patients with XLHED and thus have implications for diagnosis and treatment planning of these patients.