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Ichthyosis bullosa of Siemens

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A form of ichthyosis that is often associated with faulty KRT2 gene coding for keratin 2E


Ichthyosis is a skin disorder characterized by having a dry, thick, scaly skin. Its name is derived from the Greek ichthys meaning fish. The skin is compared to the scaly outer covering of the fish. The scaly appearance of the skin is due to excessive skin keratinization or cornification.

Ichthyosis bullosa of Siemens is a form of ichthyosis that is often due to a mutation in the KRT2 gene on chromosome 12. The gene codes for keratin 2E, which is a cytokeratin found in the upper spinous layer of the epidermal keratinocytes. This condition is autosomal dominant. This means that there is a 50% chance that the condition is inherited by the child.

Ichthyosis bullosa of Siemens involves symptoms similar to epidermolytic hyperkeratosis. However, the symptoms are milder in the former. Only the superficial layers of the skin are affected in individuals with this type of ichthyosis. At birth, the newborn skin is erythematous and may have blisters. After few weeks the erythema disappears. However, it is replaced by dry and flaking skin on arms, legs, and around the belly button.1 As the child ages, these symptoms improve but hyperkeratosis may form in localized areas, particularly on flexural folds.


  • epidermolytic hyperkeratosis
  • bullous congenital ichthyosiform erythroderma
  • bullous ichthyosiform erythroderma

See also:

1 Barnhill, R. L. & Crowson, A. N. (2004). Textbook of Dermatopathology. McGraw-Hill Professional. p349.