Autosomal recessive inheritance of a novel missense mutation of ITGB4 for Epidermolysis-Bullosa pyloric-atresia: a case report

Epidermolysis-Bullosa (EB), a rare Mendelian disorder, exhibits complex phenotypic and locus-heterogeneity. We identified a nuclear family of clinically unaffected parents with two offsprings manifesting EB-Pyloric-Atresia (EB-PA), with a variable clinical severity. We generated whole exome sequence data on all four individuals to (1) identify the causal mutation behind EB-PA (2) understand the background genetic variation for phenotype variability of the siblings. We assumed an autosomal recessive mode of inheritance and used suites of bioinformatic and computational tools to collate information through global databases to identify the causal genetic variant for the disease. We also investigated variations in key genes that are likely to impact phenotype severity. We identified a novel missense mutation in the ITGB4 gene (p.Ala1227Asp), for which the parents were heterozygous and the children homozygous. The mutation in ITGB4 gene, predicted to reduce the stability of the primary alpha6beta4-plectin complex compared to all previously studied mutations on ITGB4 reported to cause EB.