A Keratin 10 Gene Mutation (Arg156Cys) in a Japanese Patient with Bullous Congenital Ichthyosiform Erythroderma

Abstract

We described a 19-year old Japanese female with bullous congenital ichthyosiform erythroderma (BCIE) and examined the keratin gene mutation. Physical examination disclosed generalized erythema, ichthyosiform skin with scales, and erosions without palmoplantar keratoderma. Histological examination revealed hyperkeratosis with vacuolar degeneration in the granular layer of the epidermis. Sequence analysis demonstrated a C to G transition at the first position of codon 156 in the keratin 10 gene. The amino acid at codon 156 was deduced to have changed from arginine to cystine. Substitution from arginine to cysteine at codon 156 of the K 10 gene is assumed to be fatal for keratin filament assembly regardless of racial or ethnic difference.

Epidermolytic hyperkeratosis: a keratin 1 or 10 mutational event

“…The type I and II keratin gene clusters have been localized to chromosomes 17q and 12q 11 . Although an arginine to histidine base substitution at position 10 in keratin 10's 1A segment of the rod domain is the most common mutation causing epidermolytic hyperkeratosis, many other point mutations have been identified 12–17 . Keratins are expressed as intermediate filament protein pairs in a tissue‐specific and differentiation‐specific fashion 18,19 .…”

“…11 Although an arginine to histidine base substitution at position 10 in keratin 10's 1A segment of the rod domain is the most common mutation causing epidermolytic hyperkeratosis, many other point mutations have been identified. [12][13][14][15][16][17] Keratins are expressed as intermediate filament protein pairs in a tissue-specific and differentiation-specific fashion. 18,19 Errors in their formation may lead to clumped keratin filaments, keratinocyte fragility, and cytolysis.…”

A case of epidermolytic hyperkeratosis with no facial involvement associated with mutation in keratin 10

“…There is a clear genotype–phenotype correlation. Cases with keratin 1 mutations show palmoplantar involvement, whereas cases with keratin 10 mutations show no palmoplantar involvement, because keratin 10 is not expressed in suprabasal keratinocytes of the palmoplantar epidermis 4,5 . Therefore, if a patient with EHK shows no palmoplantar involvement, it should be better to screen for keratin 10 first rather than keratin 1; our patient showed no palmoplantar involvement.…”

Erythrodermia Congenitalis Ichthyosiformis Bullosa of Brocq

“…Ichthyoses can be divided into two main groups: non-congenital ichthyoses, which develop in the first weeks or months after birth (vulgar ichthyoses), and congenital ichthyoses, which are clinically seen at the day of birth [ 1 , 2 , 3 ]. Erythrodermia congenitalis ichthyosiformis bullosa of Brocq is a congenital ichthyosis caused by autosomal dominant and spontaneous mutations of keratin genes KRT-1 and KRT-10 [ 4 ]. These mutations lead to altered keratin intermediate filaments.…”

“…Clinically, this skin condition shows generalized erythema and erosions or blistering at the day of birth. Later, verrucous hyperkeratosis can often be found at the neck, the flexural areas as well as the palms and soles (especially in patients with KRT-1 mutations) [ 1 , 2 , 3 , 4 ]. To our knowledge, this is the first case of this skin condition reported in the literature with a heterozygous duplication (c.1752dupT) in KRT-1 .…”