Digital Image Analysis for Reliable Characterization of Cleft Wound Phenotypes

Cleft lip is a common birth defect with major physical and psychological impacts on affected individuals’ lives.  Satisfaction with facial appearance, which is partly affected by success/quality of surgical cleft repair, is widely reported as the single most important factor influencing psychosocial adjustment among affected individuals.  Surgical success impacts wound healing, which may be influenced by IRF6 or other clefting candidate genes.  However, understanding the genetic basis of wound healing among affected individuals requires accurate characterization of the wound healing phenotype.  Objective: To develop wound healing phenotypes measured from digital 2D and 3D images of cleft lip wounds for genotype-phenotype correlation studies.  Methods:  We used 3-D images of 68 surgically repaired unilateral cleft lip individuals captured using the 3DMD image system.  Size and RGB color histogram data of affected and control regions of the philtrum and upper lip were acquired using 3DMD and Image J software.  Reliability was determined from repeated measurements of 15 images by t-test and Interclass Correlation Coefficient (ICC) analysis.  Pearson correlation was used to analyze color similarity of several non-affected control points of the philtrum.  We compared the color of affected versus unaffected control areas using t-test analysis.  Results: Our method demonstrated high repeatability from ICC scores greater than 8.0 for all repeated area measurements except total unaffected area of the lip.  The color between philtrum controls was significantly similar based on Pearson correlation (p<0.001).  T-test analysis comparing color of the philtrum wound with the contralateral unaffected philtrum control (the most relevant control region) showed a significant color difference (p ranging from 1.20^-05 to 1.95^-14).  Conclusions: Our study establishes a new reliable method to characterize the phenotype of labial wounds in individuals with oral clefts. Correlations between genetic variants in IRF6 and other candidate genes and the wound phenotypes are currently being evaluated and will be presented.