Pitfalls of genetic diagnosis in the adolescent: the changing face.

Considerable change occurs in the face, both normal and syndromic, with age. Despite knowledge of that change, which we view in ourselves, our family and our friends every day, only recently has recognition of phenotypic change been incorporated into diagnosis of a genetic syndrome or pattern. This lack of awareness can be a substantial pitfall. Over the past 20 years, the author has studied facial change in several different conditions, using subjective and objective statistical approaches. These studies have revealed age-related changes that render the phenotype more subtle, challenging diagnostic acumen. The opposite scenario also may occur: the phenotype unfolds with age, and diagnosis in infancy and early childhood is more challenging. Syndrome-specific patterns of features can be documented objectively, along with the superimposed differential rates in facial growth that are the normal process of aging. Measurement of facial dimensions can add to or validate a subjective "gestalt" impression. A brief review of techniques available for objective assessment of the face is provided. Review of serial photographs from birth can enhance diagnostic potential by taking into account the phenotype at all ages. This approach is particularly helpful in the evaluation of adolescents and adults. Lastly, experience should never be underestimated; the opinion of a geneticist may be invaluable.