Possible anticipation in familial epidermolytic palmoplantar keratoderma with the p.R163W mutation of Keratin 9.

Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant disease characterized by diffuse hyperkeratosis of the epidermis of the palm and sole with an erythematous margin. The Keratin 9 (KRT9) and Keratin 1 genes are responsible for EPPK. Several previous studies have focused on the genetic basis of EPPK; however, genetic anticipation has not yet been reported. We described a four-generation family with EPPK and identified a p.R163W mutation of KRT9. We observed a decrease in the age of onset in three consecutive generations in the family of the proband, indicating possible genetic anticipation in this familial EPPK. Further studies are needed to elucidate the mechanisms of anticipation in EPPK.