A novel homozygous deletion in EXPH 5 causes a skin fragility phenotype

Summary Epidermolysis bullosa simplex ( EBS ) is the most common form of EB . Eight different genes have been implicated in the pathogenesis of different types of EBS , but a substantial portion of the cases cannot be attributed to mutations in known genes. Recently, recessive mutations in the gene EXPH 5 (encoding exophilin‐5, also known as Slac2‐b) were identified in patients affected with a mild form of EBS . We used immunohistochemistry, Sanger sequencing and PCR –restriction fragment length polymorphism analysis to identify the cause of mild congenital skin fragility in a 3‐year‐old girl. No mutations were detected in KRT 5 or KRT 14 , but we identified a novel homozygous deletion in EXPH 5 , which was found to cosegregate with the disease phenotype in the family. Our results further expand the spectrum of mutations in EXPH 5 . Appraisal of the present case against previously reported patients indicate that EXPH 5 mutations result in a distinctive skin fragility phenotype, with minimal blistering compared with other forms of basal EBS .