Morphometry of the ear in north Sudanese subjects with Down syndrome: a three-dimensional computerized assessment.

Down syndrome (DS) is the most frequent live-born autosomal aneuploidy in humans. Scanty data on the craniofacial phenotype of African subjects with DS have been published so far. We wanted to detail the morphologic characteristics of the ears in north Sudanese subjects with DS. The three-dimensional coordinates of 13 soft-tissue landmarks on the ears were obtained using a laser scanner in 64 north Sudanese subjects with DS aged 4 to 34 years and in 682 sex- and age-matched control subjects. From the landmarks, left and right linear distances (ear width and length), ratios (ear width-to-ear length), areas (ear area), angles (angle of the auricle vs the facial midplane), and the three-dimensional symmetry index were calculated. Distances, angles, areas, and ratios were computed. Subject and reference data were compared by computing z scores and calculating Student t tests. Ear width, length, and area were significantly (Student t test, P < 0.001) smaller in the subjects with DS than in the reference subjects. On the right side of the face, the subjects with DS had larger ear width-to-ear length ratios and larger angles of the auricle versus the facial midplane than the reference subjects. The three-dimensional symmetry index was significantly larger in the reference subjects. In conclusion, ear dimensions, position, and shape significantly differed in subjects with DS when compared with sex-, age-, and ethnic group-matched control subjects.

Three-dimensional assessment of nose and lip morphology in North Sudanese subjects with Down syndrome.

OBJECTIVE: To detail the nasolabial morphologic characteristics of North Sudanese subjects with Down syndrome (DS). MATERIALS AND METHODS: Nasolabial morphology was assessed three-dimensionally in 64 North Sudanese subjects with DS aged 4 to 34 years and in 682 sex- and age-matched controls. Three-dimensional facial coordinates were collected using a laser scan, and selected distances, angles, areas, and volumes were computed. Subject and reference data were compared by computing z-scores and Student's t-tests. RESULTS: The nose was significantly smaller (area) in subjects with DS than in reference subjects, and it had a different shape (more flat angle of alar slope, more acute nasal tip angle). The vertical (nasal bridge length, nose height) and anteroposterior (nasal tip protrusion) dimensions were reduced, while the horizontal dimensions (alar base width, inferior widths of the nostrils) were increased. The nasolabial angle was increased. The cutaneous lip volume was significantly smaller, while the vermilion lip area was larger in the subjects with DS. The mouth and philtrum widths were significantly reduced, while the vermilion height was significantly increased. CONCLUSION: Analyzed subjects with DS had a hypoplastic nose and different upper and lower lips than did reference, normal subjects.