Ichthyosis

Ichthyosis is a family of rare genetic skin disorders characterized by dry, thickened, scaly skin.see also Template:Congenital malformations and deformations of skin appendages, Template:Phakomatoses, Template:Pigmentation disorders, Template:DNA replication and repair-deficiency disorder Ichthyosis is a family of rare genetic skin disorders characterized by dry, thickened, scaly skin. The more than 20 types of ichthyosis range in severity of symptoms, outward appearance, underlying genetic cause, and mode of inheritance (e.g., whether the abnormal gene inherited is dominant, recessive, autosomal or X-linked). Ichthyosis comes from the Greek ἰχθύς, ichthys, literally 'fish', since dry, scaly skin is the defining feature of all forms of ichthyosis. The severity of symptoms can vary enormously, from the mildest, most common, types such as ichthyosis vulgaris, which may be mistaken for normal dry skin, up to life-threatening conditions such as harlequin-type ichthyosis. Ichthyosis vulgaris accounts for more than 95% of cases. Many types of ichthyoses exist, and an exact diagnosis may be difficult. Types of ichthyoses are classified by their appearance and their genetic cause. Ichthyosis caused by the same gene can vary considerably in severity and symptoms. Some ichthyoses do not appear to fit exactly into any one type. Different genes can produce ichthyoses with similar symptoms. Of note, X-linked ichthyosis is associated with Kallmann syndrome (close to the KAL1 gene). The most common or well-known types are: A physician often can diagnose ichthyosis by looking at the skin. A family history is very useful. In some cases, a skin biopsy is done to help to confirm the diagnosis. In some instances, genetic testing may be helpful in making a diagnosis. Diabetes has not been definitively linked to acquired ichthyosis or ichthyosis vulgaris; however, there are case reports associating new onset ichthyosis with diabetes.