Craniofacial and upper airway cephalometrics in hypohidrotic ectodermal dysplasia

The aim of this study was to evaluate the craniofacial and upper airway structures in patients with hypohidrotic ectodermal dysplasia (HED). Craniofacial and upper airway dimensions were measured on lateral cephalometric radiographs of ten HED patients (four females and six males) and ten normal class III patients as a control group. 21 dimensional measurements were used for cephalometric assessment. Craniofacial structures were compared with normal values and airway dimensions were compared with those of a control group with a similar skeletal pattern. We found that the SNA degrees, SNB degrees, ANB degrees, SN-GoMe degrees and the distance between the lips and the S-line were lower than those in normal subjects, while soft tissue convexity angles were higher in HED patients. Statistically significant decreases occurred in tongue length, vertical airway length, hyoid bone mandibular plane length, hyoid bone C3 length, middle airway space and inferior airway space, while the soft palate length increased. The characteristic craniofacial features of HED patients are class III malocclusion with maxillary retrusion and deficiency in vertical, transversal and sagittal growth of the jaw and soft tissues. HED patients have smaller pharyngeal and upper airway dimensions, and the hyoid bone is positioned more posteriorly compared with class III control individuals.