ichthyosis congenita


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Related to ichthyosis congenita: Congenital ichthyosis

ichthyosis

 [ik″the-o´sis]
any in a group of skin disorders characterized by increased or aberrant keratinization, resulting in dryness, roughness, and scaliness of the skin. Many different metaphors such as alligator, collodion, crocodile, fish, and porcupine skin have been used to describe the various types and stages of ichthyosis. Most ichthyoses are genetically determined, but some may be acquired and develop in association with systemic diseases or may be a prominent feature in certain genetic syndromes. The term is commonly used alone to refer to ichthyosis vulgaris. (See Atlas 2, Part L.) adj., adj ichthyot´ic.
ichthyosis conge´nita (congenital ichthyosis) lamellar exfoliation of newborn.
harlequin ichthyosis the ichthyosis affecting a harlequin fetus.
ichthyosis hys´trix a rare form of epidermolytic hyperkeratosis marked by generalized, dark brown, linear, wartlike ridges somewhat like porcupine skin.
lamellar ichthyosis a congenital, chronic form of ichthyosis present at birth, inherited as an autosomal recessive trait, in which the affected infant is born encased in a collodionlike membrane (see collodion baby) that is soon shed, the skin then becoming covered with large, coarse scales with involvement of all of the flexures as well as the palms and soles. Universal erythroderma and pruritus are characteristic, and ectropion of variable degree is usually present. Formerly called congenital ichthyosiform erythroderma (nonbullous type). (See Atlas 2, Part K.)
lamellar ichthyosis of newborn lamellar exfoliation of newborn.
ichthyosis linea´ris circumflex´a a congenital autosomal recessive disorder present at birth, characterized by the presence of generalized redness and scaling of the skin associated with migratory lesions and hyperhidrosis of the palms and soles.
ichthyosis vulga´ris the most common form of ichthyosis, inherited as an autosomal dominant trait, having an onset sometime after the first year of life, especially near puberty. There is prominent fine scaling, principally on the extensor surfaces of the extremities and back (the flexures are spared and there is little scaling of the abdomen and face), together with accentuated markings and creases on the palms and soles; atopy is often present.
X-linked ichthyosis a chronic form of ichthyosis affecting only males, transmitted as an X-linked recessive trait, that may be present at birth or appear in early infancy. It is characterized by the presence of prominent, very adherent scales, often brown, especially on the neck, extremities, trunk, and buttocks.

lam·el·lar ich·thy·o·sis

[MIM*242300]
a dry form of congenital ichthyosiform erythroderma, characterized by ectropion and large, coarse scales over most of the body with thickened palms and soles; may be fatal with complications of sepsis, protein, and electrolyte loss in the first year of life; histology shows hyperkeratosis, a prominent granular layer in the epidermis, slight acanthosis, many mitotic figures, and normal or reduced epidermal cell turnover. Autosomal recessive inheritance, caused by mutation in the gene encoding keratinocyte transglutaminase (TGM1) on chromosome 14q.
See also: collodion baby, harlequin fetus.

ichthyosis congenita, ichthyosis fetalis

See lamellar exfoliation.

autosomal recessive congenital ichthyosis

A clinically and genetically heterogeneous group of inherited disorders (ARCIs) of keratinisation, with an estimated incidence of 1:50,000–200,000 newborns.
A rare autosomal recessive [MIM 242500] disease of infants in which the baby is encased in a hyperkeratotic ‘coccoon’ with deep fissures, accompanied by ectropion. Harlequin ichthyosisis a severe dyskeratosis, caused by defective lipid metabolism; the stratum corneum is up to 30-fold thicker than the stratum malpighii; the stratum granulosa is decreased to a one-cell layer or absent