A novel keratin 9 gene mutation (Asn160His) in a Taiwanese family with epidermolytic palmoplantar keratoderma

Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant inherited disorder of keratinization. Recent molecular studies have shown that EPPK is caused by mutations in keratin 9 gene (KRT9). We report a Taiwanese family with EPPK with a novel mutation with an A → C transition at the first nucleotide of codon 160 in KRT9. The mutation is predicted to result in an asparagine to histidine substitution (N160H) at the beginning of the α-helical 1A domain of keratin 9. Mutations in this region could disrupt keratin filament assembly, leading to degeneration or cytolysis of keratinocytes. Our mutation analysis confirms that codon 160 in KRT9 is one of the mutation hot spots in EPPK.