De novo GLI3 mutation in esophageal atresia: reproducing the phenotypic spectrum of Gli3 defects in murine models.

Esophageal atresia is a common and life-threatening birth defect with a poorly understood etiology. In this study, we analyzed the sequence variants of coding regions for a set of esophageal atresia-related genes including MYCN, SOX2, CHD7, GLI3, FGFR2 and PTEN for mutations using PCR-based target enrichment and next-generation sequencing in 27 patients with esophageal atresia. Genomic copy number variation analysis was performed using Affymetrix SNP 6.0. We found a de novo heterozygous mutation in the N-terminal region of the GLI3 gene (c.332T>C, p.M111T) in a patient with esophageal atresia and hemivertebrae. The N-terminal region (amino acids 1-397) of GLI3 contains the repressor domain, which interacts with SKI family proteins. Using the co-immunoprecipitation assay, we found that interaction of GLI3 with the SKI family protein SKIL was significantly compromised by the p.M111T mutation of GLI3. Thus far, all the identified mutations mapped within the repressor domain of GLI3 were nonsense and frame-shift mutations. In this study, a missense mutation was initially detected in this region. Our finding is the first to link this GLI3 gene mutation with esophageal atresia in humans, which was previously suggested in an animal model.