title: Keratin 1 gene mutation detected in epidermal nevus with epidermolytic hyperkeratosis.
abstract: Since 1994, four cases of epidermal nevus with epidermolytic hyperkeratosis (EH) caused by keratin 10 gene mutations have been reported, although no keratin 1 (K1) gene mutation has yet been reported. We detected a K1 gene (KRT1) mutation in epidermal nevus with EH in a 10-year-old Japanese male. The patient showed well-demarcated verrucous, hyperkeratotic plaques mainly on the trunk, covering 15% of the entire body surface. No hyperkeratosis was seen on the palms or soles. He had no family history of skin disorders. His lesional skin showed typical granular degeneration and, ultrastructurally, clumped keratin filaments were observed in the upper epidermis. Direct sequence analysis of genomic DNA extracted from lesional skin revealed a heterozygous 5' donor splice site mutation c.591+2T>A in KRT1. This mutation was not detected in genomic DNA samples from the patient's peripheral blood leukocytes or those of other family members. The identical splice mutation was previously reported in a family with palmoplantar keratoderma and mild ichthyosis, and was demonstrated to result in a 22 amino-acid deletion p.Val175_Lys196del in the H1 and 1A domains of K1. To our knowledge, the present patient is the first reported case of epidermal nevus associated with EH caused by a K1 gene mutation in a mosaic pattern.
authors.affiliation: Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Tsubota
authors.forename: Masashi
authors.initials: M
authors.lastname: Akiyama
authors.forename: Kaori
authors.initials: K
authors.lastname: Sakai
authors.forename: Maki
authors.initials: M
authors.lastname: Goto
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Nomura
authors.forename: Satomi
authors.initials: S
authors.lastname: Ando
authors.forename: Masataka
authors.initials: M
authors.lastname: Abe
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sawamura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shimizu
mesh_terms: D002648:Child; D004817:Epidermis / Q000378:metabolism / Q000473:pathology; D015870:Gene Expression; D006801:Humans; D017488:Hyperkeratosis, Epidermolytic / Q000235:genetics* / Q000473:pathology; D053556:Keratin-1 / Q000235:genetics* / Q000378:metabolism; D008297:Male; D009506:Nevus / Q000235:genetics* / Q000473:pathology; D017354:Point Mutation; D022821:RNA Splice Sites / Q000235:genetics
chemical_list: C491616:KRT1 protein, human; D053556:Keratin-1; D022821:RNA Splice Sites