A new keratin 5 mutation (K199T) in a family with Weber-Cockayne epidermolysis bullosa simplex.

A new missense mutation in the keratin 5 gene (KRT5) in a Chinese family with Weber-Cockayne type epidermolysis bullosa simplex is reported. Direct sequencing identified a heterozygous A --> C substitution at nucleotide 596 altering codon 199 of KRT5 from lysine to threonine in all affected family members, but not in the unaffected family members or in 50 unrelated control samples. The mutation is designated K199T. This mutated lysine residue is sited within the 1A domain of keratin 5 and is highly conserved among all type II keratins. The mutation may perturb the alignment of tonofilaments and, as a consequence, result in skin fragility and blistering.