Title: Facial Integration in Unaffected Relatives of Individuals With Orofacial Clefts
Steven Miller (Presenter)
Seth Weinberg, University of Pittsburgh
Nichole Nidey, University of Iowa
Mary Marazita, University of Pittsburgh
George Wehby, University of Iowa
Lina Moreno-Uribe, University of Iowa
Objectives: Orofacial clefts (OFCs) result from a failure of frontonasal process derivatives to unite with the adjacent maxillary processes during embryogenesis, indicating a lack of integration in these developmental units. Facial shape differences have long been documented in the unaffected relatives of individuals with OFCs, suggesting the incomplete phenotypic expression of cleft risk genes. This study examines patterns of morphological integration within the faces of these unaffected relatives. Specifically, we test the hypothesis that unaffected relatives will have lower degrees of facial integration when compared to the faces of control individuals with no known family history of orofacial clefts.
Methods: In order to test this hypothesis, 3D facial scans of n=194 controls and n=188 first degree unaffected relatives of individuals with OFCs from eastern Iowa were landmarked along the nose (11 landmarks), mouth (7 landmarks), and mandible (5 landmarks) in order to capture true shape variation in these structures. These facial sub-units were then submitted to a series of two-block partial least squares analyses (2B PLS) to identify the strength of correlation (RV coefficient) between each sub-unit.
Results: 2B PLS results show higher levels of morphological integration between the nose and mouth in controls (RV = 0.23, p<0.0001) compared to relatives (RV = 0.19, p<0.0001) as well as the nose and mandible (control RV = 0.13, p<0.0001, relative RV = 0.07, p<0.0001). Interestingly, levels of integration are decreased in the lower face between the mouth and mandible in the control sample (RV = 0.09, p<0.0001) when compared to the unaffected relatives (RV = 0.11, p<0.0001).
Conclusions: Findings from this study indicate higher levels of integration between the nose and lower facial structures (mouth, mandible) in controls compared to unaffected relatives of individuals with OFCs, indicating that increased risk for OFCs may be related to lower levels of facial integration.