Soft tissue facial areas and volumes in individuals with ectodermal dysplasia : a three-dimensional non invasive assessment

The objective of this study was to supply quantitative information about the facial soft-tissues of a group of patients with hypohidrotic ectodermal dysplasia. The three-dimensional coordinates of 28 soft-tissue facial landmarks were obtained by an electromagnetic digitizer in 11 male and 9 female patients with hypohidrotic ectodermal dysplasia aged 7-41 years, and in 318 healthy individuals of the same age, ethnicity, and sex. From the landmarks, facial areas (eyes, ears, nose, and lips) and volumes (nose and lips) were calculated according to a geometrical model of face. Data were compared to those collected in the normal subjects by computing z-scores. Male and female z-scores were not significantly different. In the pooled sample, the deviations from the norm were particularly evident in the lips, with a significant (Student's t-test, P < 0.05) increment of the total lip area (mean z-score: 0.96) and of the vermilion area of the upper lip (mean z-score: 1.07), a finding negatively related (r = -0.632) to the number of teeth present in the mouth. The eye area was reduced in most patients, a finding significant on the left side (mean z-score: -0.76). Most of the facial areas and volumes of the ectodermal dysplasia patients had z-scores deviating only +/-2 standard deviations from the reference groups. Only 4% of measurements had z-scores larger than +/-3. Additionally, a large inter-individual variability was found, together with a certain age-related trend of improvement of the number of measurements within the +/-2 interval. The method allowed a simple, low cost, fast, and non invasive examination of the patients, and provided a quantitative assessment of the deviation from the norm.