The reference OMIM entry for this protein is 146800

Ichthyosis bullosa of siemens; ibs
Ichthyosis, bullous type ichthyosis exfoliativa, included

A number sign (#) is used with this entry because ichthyosis bullosa of Siemens (IBS) is caused by heterozygous mutation in the KRT2 gene (600194) on chromosome 12q13.

CLINICAL FEATURES

Schnyder (1970) concluded that the bullous type of ichthyosis, called ichthyosis bullosa of Siemens (Siemens, 1937), represents a distinct entity. IBS is a rare autosomal dominant disorder that is highly penetrant and clinically evident from birth. In affected individuals, the clinical findings are similar to those of epidermolytic hyperkeratosis (EHK; 113800). IBS patients are born with a generalized reddening of the skin (erythema) and widespread blistering. In later weeks, they develop large, dark gray hyperkeratoses predominantly on their arms and legs and particularly on the flexural areas where the hyperkeratoses have a lichenified appearance (Traupe et al., 1986; Steijlen et al., 1990). The skin on the limbs of these patients bruises easily and blisters are readily induced by mild physical trauma. The condition usually improves with age so that in most middle-aged patients the hyperkeratosis and keratotic lichenification is limited to the flexural folds of the major joints. As is the case for EHK and most autosomal dominant disorders, IBS patients exhibit a wide variability in the severity of their symptoms. Siemens (1937), who first made the distinction between EHK and IBS, noted that the skin of IBS patients was unusually fragile and had a tendency to shed the outer layers of the epidermis, producing localized denuded areas. He applied the term 'Mauserung' (molting) to this distinctive clinical finding. Siemens' work was largely overlooked until Traupe et al. (1986) reported histologic and ultrastructural findings on a second family with IBS. In a family with IBS reported by Steijlen et al. (1990), affected individuals had brownish rippled hyperkeratosis and superficial blistering from early childhood. Blistering was more pronounced during hot and humid weather and could be provoked by mild trauma. Erythroderma had never been present in any of the affected persons. Skin lesions were localized, especially on the extensor surfaces of the arms and legs and around the umbilicus, knees, and ankles. In the hyperkeratotic regions, superficially denuded areas were present. Occasionally, fresh blisters ranging in size from 0.5 to 2 cm appeared. On ultrastructural examination of the skin, keratinocytes in the upper spinous layer displayed aggregates of tonofilaments forming V shapes or shells around the nuclei. - Ichthyosis Exfoliativa Ichthyosis exfoliativa is an autosomal dominant skin disorder described by Vakilzadeh and Kolde (1991) in a single family. The clinical manifestations were similar to those of IBS, but the histologic features of epidermolytic hyperkeratosis were absent. The patients showed dark gray hyperkeratotic lesions with denuded areas. Superficial blistering occurred spontaneously, especially during the summer, but occurred also after trivial trauma. There was no history of erythroderma. On electron microscopic examination, it was said that 'the number of tonofilaments and keratohyaline granules were markedly reduced with no grouping of the tonofilaments.'

NOMENCLATURE

Epidermolytic hyperkeratosis is a histopathologic characteristic of a variety of monogenic keratinization disorders comprising bullous congenital ichthyosiform erythroderma of Brocq, epidermolytic palmoplantar keratoderma of Vorner (EPPK; 144200), ... More on the omim web site

Subscribe to this protein entry history

Oct. 20, 2018: Protein entry updated
Automatic update: OMIM entry 146800 was added.

Oct. 19, 2018: Additional information
Initial protein addition to the database. This entry was referenced in Bryk and co-workers. (2017).