ichthyosis ichthyosis ichthyosis is a family of 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., 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. ichthyosisother namesichthyosesichthyosis is characterized by generalised, scaly skin.specialtydermatology 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. types many types of ichthyoses exist, and an exact diagnosis may be difficult. types of ichthyoses are classified by their appearance, if they are syndromic or not, and by mode of inheritance. for example, non-syndromic ichthyoses that are inherited recessively come under the umbrella term autosomal recessive congenital ichthyosis (arci). ichthyosis caused by mutations in the same gene can vary considerably in severity and symptoms. some ichthyoses do not appear to fit exactly into any one type while mutations in 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: non-syndromic ichthyosis name omim mode of inheritance gene(s) ichthyosis vulgaris 146700 autosomal semi-dominant flg x-linked recessive ichthyosis 308100 x-linked recessive sts harlequin ichthyosis 242500 autosomal recessive abca12 congenital ichthyosiform erythoderma 242100 autosomal recessive tgmi1, nipal4, alox12b, aloxe3, abca12, cyp4f22, nipal4, lipn, cers3, pnpla1, st14, casp14 lamellar ichthyosis 242300 autosomal recessive tgmi1, nipal4, alox12b, aloxe3, abca12, cyp4f22, nipal4, lipn, cers3, pnpla1, st14, casp14 self improving congenital ichthyosis 242300 autosomal recessive tgm1, alox12b, aloxe3 bathing suit ichthyosis 242300 autosomal recessive tgmi1 epidermolytic ichthyosis 113800 autosomal dominant krt1, krt10 superficial epidermolytic ichthyosis 146800 autosomal dominant krt2 annular epidermolytic ichthyosis 607602 autosomal dominant krt1, krt10 ichthyosis curth-macklin 146590 autosomal dominant krt1 autosomal recessive epidermolytic ichthyosis 113800 autosomal recessive krt10 congenital reticular ichthyosiform erythroderma 609165 autosomal dominant krt1, krt10 epidermolytic nevi 113800 postzygotic mosaicism krt1, krt10 loricrin keratoderma 604117 autosomal dominant lor erythrokeratodermia variabilis 133200 autosomal dominant gjb3, gjb4 peeling skin disease 270300 autosomal recessive cdsn keratosis linearis with ichthyosis congenita and sclerosing keratoderma 601952 autosomal recessive pomp syndromic ichthyosis name omim mode of inheritance gene (s) x-linked recessive ichthyosis syndromic forms 308700 300500 300533 x-linked recessive sts ichthyosis follicularis with alopecia and photophobia syndrome 308205 x-linked recessive mbtps2 conradi-hunermann-happle syndrome 302960 x-linked dominant ebp netherton syndrome 256500 autosomal recessive spink5 ichthyosis-hypotrichosis syndrome 610765 autosomal recessive st14 trichothiodystrophy 601675 autosomal recessive ercc2, ercc3, gtf2h5 trichothiodystrophy (non-congenital forms) 275550 211390 601675 autosomal recessive c7orf11, ttdn1 sjögren-larsson syndrome 270200 autosomal recessive aldh3a2 refsum's disease 266500 autosomal recessive phyh, pex7 mental retardation, enteropathy, deafness, neuropathy, ichthyosis, keratoderma syndrome 609528 autosomal recessive snap29 arthrogryposis, renal dysfunction, cholestasis syndrome 208085 autosomal recessive vps33b keratitis-ichthosis-deafness syndrome 602450 148210 autosomal dominant gjb2 neutral lipid storage disease with ichthyosis 275630 autosomal recessive abhd5 ichthyosis prematurity syndrome 608649 autosomal recessive slc27a4 neu–laxova syndrome 256520 616038 autosomal recessive phgdh , psat1 and psph non-genetic ichthyosis ichthyosis acquisita diagnosis a physician often can diagnose ichthyosis by looking at the skin. a family history is also useful in determining the mode of inheritance. in some cases, a skin biopsy is done to help to confirm the diagnosis while in others 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. ichthyosis has been found to be more common in native american, asian, mongolian groups. there is no way to prevent ichthyosis. ichthyosis is a genetically and phenotypically heterogeneous disease that can be isolated and restricted to the skin manifestations or associated with extracutaneous symptoms. one of which is limb reduction defect known as child syndrome; a rare inborn error of metabolism of cholesterol biosynthesis that is usually restricted to one side of the body. one case with symptoms matching child syndrome has been described as having a likely-different cause. treatments treatments for ichthyosis often take the form of topical application of creams and emollient oils, in an attempt to hydrate the skin. creams containing a high percentage of urea or lactic acid have been shown to work exceptionally well in some cases. application of propylene glycol is another treatment method. retinoids are used for some conditions. exposure to sunlight may improve or worsen the condition. in some cases, excess dead skin sloughs off much better from wet tanned skin after bathing or a swim, although the dry skin might be preferable to the damaging effects of sun exposure. there can be ocular manifestations of ichthyosis, such as corneal and ocular surface diseases. vascularizing keratitis, which is more commonly found in congenital keratitis-ichythosis-deafness (kid), may worsen with isotretinoin therapy. other animals ichthyosis or ichthyosis-like disorders exist for several types of animals, including cattle, chickens, llamas, mice, and dogs. ichthyosis of varying severity is well documented in some popular breeds of domestic dogs. the most common breeds to have ichthyosis are golden retrievers, american bulldogs, jack russell terriers, and cairn terriers.