Three-dimensional assessment of nose and lip morphology in subjects with down syndrome.

Nasolabial morphology was assessed 3-dimensionally in 28 subjects with Down syndrome aged 12-45 years and in 449 sex- and age-matched controls. Subject and reference data were compared by computing z scores and calculating Student's t tests. The nose was significantly smaller (volume, area) in the subjects with Down syndrome than in the reference subjects, and it had a different shape (more flat angle of alar slope, more acute nasal tip angle). The vertical (length of the nasal bridge, height of the nose) and anteroposterior (nasal tip protrusion) dimensions were reduced, while the horizontal dimensions (alar base width, superior and inferior widths of the nostrils) were increased. The lower lip was significantly smaller (volume, area, vermilion height), while the upper lip was larger (area, vermilion height) in the subjects with Down syndrome. The mouth width was also significantly smaller. In conclusion, the analyzed subjects with Down syndrome had a hypoplastic nose and different upper and lower lips than reference, normal subjects.