Case Report: Alpha6 Integrin Disorder Presenting in Childhood with Nail Dysplasia and Onycholysis But No History of Fragile or Bullous Skin Changes.

Abstract

We report a 7-year-old girl born with pyloric atresia but without congenital epidermolysis bullosa or skin fragility. Nail dysplasia developed at age 8 months and throughout childhood she suffered from onycholysis and mild nail hypertrophy. Whole-exome sequencing demonstrated biallelic mutations in alpha6 integrin (ITGA6): p. Q139* and R153W. ITGA6 normally forms a protein heterodimer with beta4 integrin (ITGB4), and this dimer participates in anchoring the basal skin cells to the extracellular matrix. Biallelic mutations in each gene are well known to cause epidermolysis bullosa and pyloric atresia. However, this child had ostensibly normal skin without any evidence of skin fragility. In a literature search, we identified 11 cases involving ITGA6 mutations, and all had epidermolysis skin changes. Thus, this case adds to the reported phenotype of ITGA6 disease since it is the first to show absence of an epidermolysis bullosa phenotype in the setting of pyloric atresia and nail dysplasia.