Defects in genes for keratin 1 (KRT1) and 10 (KRT10) are the cause of epidermolytic ichthyosis. [1, 2, 3, 4, 5] Usually, these mutations are missense substitutions into the highly conserved alpha-helical rod and the nonhelical H1 domains of the keratin proteins. [6]
Palmoplantar keratoderma is usually associated with KRT1 mutations; however, in rare cases, palmoplantar keratoderma may be observed in patients with KRT10 mutations. [7] Novel mutations in both genes continue to be reported.
Patients with generalized epidermolytic ichthyosis may be born to parents with epidermolytic epidermal nevi (mosaic epidermolytic ichthyosis). [8, 9] Epidermal nevi with histologic changes of epidermolytic hyperkeratosis are caused by postzygotic mutations in keratin 1 or keratin 10. If the mutation also involves gonadal cells, which is thought to be more likely in patients with more extensive cutaneous involvement, affected individuals can have offspring with generalized epidermolytic ichthyosis.
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Pathology of epidermolytic ichthyosis (hematoxylin and eosin stain).
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Pathology of epidermolytic ichthyosis (hematoxylin and eosin stain).
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The scale in epidermolytic ichthyosis is classically described as "corrugated". Patients often experience erosions as a result of skin fragility.
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The scale in epidermolytic ichthyosis is classically described as "corrugated". Patients often experience erosions as a result of skin fragility.
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Palms and soles may have varying degrees of hyperkeratosis.
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Hyperkeratosis involving the abdomen.
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Hyperkeratosis involving the knee.
