Epidermolytic hyperkeratosis 1(EHK1)

MedGen UID:: 1826137
•Concept ID:: C5781874
•: Disease or Syndrome

Synonyms:	BULLOUS CONGENITAL ICHTHYOSIFORM ERYTHRODERMA; EHK1

Gene (location): Gene(s) directly associated with this condition or phenotype.	KRT1 (12q13.13)

Monarch Initiative:	MONDO:0700249
OMIM®:	113800

Definition

Epidermolytic hyperkeratosis-1 (EHK1) is a rare autosomal dominant disorder of cornification. The disorder usually presents at birth with erythema and blistering and is characterized in adulthood by warty flexural hyperkeratosis with fewer erosions and blisters. Ultrastructural analysis reveals clumping of the intermediate filaments within keratinocytes of the spinous and granular layers (summary by Whittock et al., 2001). A form of epidermolytic hyperkeratosis that is limited to the palms and soles, designated palmoplantar keratoderma (EPPK; 144200), can also be caused by mutation in KRT1, as well KRT9 (607606). Genetic Heterogeneity of Epidermolytic Hyperkeratosis Mutation in the KRT10 gene (148080) results in both autosomal dominant (EHK2A; 620150) and autosomal recessive (EHK2B; 620707) forms of epidermolytic hyperkeratosis. [from OMIM]

Clinical features

From HPO

Palmoplantar keratosis

MedGen UID:: 44017
•Concept ID:: C0022596
•: Disease or Syndrome

Abnormal thickening of the skin localized to the palm of the hand and the sole of the foot.

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Erythroderma

MedGen UID:: 3767
•Concept ID:: C0011606
•: Disease or Syndrome

An inflammatory exfoliative dermatosis involving nearly all of the surface of the skin. Erythroderma develops suddenly. A patchy erythema may generalize and spread to affect most of the skin. Scaling may appear in 2-6 days and be accompanied by hot, red, dry skin, malaise, and fever.

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Epidermolytic ichthyosis

MedGen UID:: 38179
•Concept ID:: C0079153
•: Disease or Syndrome

Epidermolytic hyperkeratosis is a skin disorder that is present at birth. Affected babies may have very red skin (erythroderma) and severe blisters. Because newborns with this disorder are missing the protection provided by normal skin, they are at risk of becoming dehydrated and developing infections in the skin or throughout the body (sepsis).\n\nAs affected individuals get older, blistering is less frequent, erythroderma becomes less evident, and the skin becomes thick (hyperkeratotic), especially over joints, on areas of skin that come into contact with each other, or on the scalp or neck. This thickened skin is usually darker than normal. Bacteria can grow in the thick skin, often causing a distinct odor.\n\nEpidermolytic hyperkeratosis can be categorized into two types. People with PS-type epidermolytic hyperkeratosis have thick skin on the palms of their hands and soles of their feet (palmoplantar or palm/sole hyperkeratosis) in addition to other areas of the body. People with the other type, NPS-type, do not have extensive palmoplantar hyperkeratosis but do have hyperkeratosis on other areas of the body.\n\nEpidermolytic hyperkeratosis is part of a group of conditions called ichthyoses, which refers to the scaly skin seen in individuals with related disorders. However, in epidermolytic hyperkeratosis, the skin is thick but not scaly as in some of the other conditions in the group.

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Epidermal acanthosis