Technique:
(1) A photograph is taken with the infant having a relaxed facial expression.
(2) The photograph should be taken with proper alignment and exposure.
(3) The photograph can then be analyzed for phenotypic features.
Facial features which are measured:
(1) palpebral fissure lengths: distance in centimeters between the outer and inner canthi
(2) inner canthal distance: distance in centimeters between the left and right inner canthi
(3) philtrum smoothness: involving the area of the upper lip and the subnasion, with focus on the midline vertical furrow bordered by 2 vertical ridges
(4) upper lip thinness: involves the upper lip as demarcated by the vermilion border
Grading of philtrum smoothness using a Likert scale
(1) deeply furrowed
(2) somewhat furrowed
(3) mid range
(4) somewhat smooth
(5) very smooth
Upper lip thinness can be estimated based on its circularity, with a thinner lip having a larger circularity.
upper lip circularity =
= ((perimeter in cm) ^2) / (area in square cm)
discriminant score =
= 1.1075 - (6.0082 * (palpebral fissure length in cm) / (inner canthal distance in cm)) + (1.1448 * (philtrum Likert score)) + (0.0066 * (upper lip circularity))
Interpretation:
• A discriminant score > 0.7 was found to be 100% accurate in identifying infants affected by the fetal alcohol syndrome.
Limitations:
• A poor photographic image may compromise the analysis.
