The form of genetic ichthyosis often associated with a defective gene(s) resulting in hyperkeratosis, especially the palms and the soles, and in the formation of large, coarse scales over the body
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.
Lamellar ichthyosis is a form of ichthyosis. The affected newborn appears to have an extra skin layer (called collodion membrane) that is shiny and waxy in appearance. This collodion-like extra layer of skin in newborns is shed in one to two weeks after birth. However, it is replaced by scales over the skin, which is one of the main symptoms of this condition. The scaling of the skin is due to hyperkeratosis. As the child ages, the scaling becomes concentrated over certain areas, particularly on flexural folds.
Lamellar ichthyosis is autosomal recessive, which means that the child will exhibit this condition when he or she inherits two copies of the defective autosomal gene associated with this genetic disorder. An individual carrying only one copy of the defective gene usually will not exhibit the symptoms of this condition. Lamellar ichthyosis may be classified as type 1, type 2, type 3, type, 4, and type 5, depending on the gene involved. Type 1 is due to a defective TGM1 gene, type 2, a defective ABCA12 gene, type 3, a defective CYP4F22 gene, type 4, a defective LIPN gene, and type 5, a defective ALOXE3 gene.
- ichthyosis lamellaris
- nonbullous congenital ichthyosis