Familiar occurrence of facial asymmetry: a pilot study.

Background: The point at which "normal" asymmetry becomes "abnormal" can be defined by an aesthetic limit and a functional limit. The underlying causes are still not fully discovered; the etiology includes congenital disorders, acquired diseases, and traumatic and developmental deformities. Our purpose was to investigate the possible genetic liability in the transmissibility of the asymmetric traits, through an analysis developed by twofold approach: 1) exploring and recording the family history through the use of a specific questionnaire; and 2) examining differences in laterality between the patients and their corresponding parent by a facial analysis.

Methods: A total of 52 Italian subjects (57% females, 43% males; mean age: 11.7 years), showing a clinically detectable asymmetry, were selected. Individuals in the sample were selected according to the diagnosis of facial asymmetry, non-syndromic patients, participation by informed consent, and negative medical history of the maxillo-facial complex. A specifically designed questionnaire was used to investigate the presence of the asymmetric trait in the family. Differences in length between distance from the anthropometric points to the facial midline and to horizontal reference were measured on a frontal facial photograph. For all the subjects recruited the same analysis was performed on the frontal facial photographs of both the parents. A descriptive and interferential statistical analysis was performed on the data.

Results: Concerning the linear measurement, in a high percentage of parent-child pairs there is a correspondence of laterality of asymmetry traits, with a more common relation with the maternal trait. Sixty-five percent of parents with correspondence of laterality reported a positive family history of asymmetry.

Conclusions: The analysis of the obtained data shows that the mother is the parent most involved in the correspondence of laterality. Further analysis would be appropriate to investigate this result.