Ichthyosis Ichthyosis Ichthyosis is a family of rare genetic skin disorders characterized by dry, thickened, scaly skin. There are more than 20 types of ichthyosis which 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
Heterogeneous condition Heterogeneous condition Heterogeneous medical condition in medicine are those medical conditions which have several etiologies, like hepatitis or diabetes. Medical conditions are normally defined pathologically (liver inflammation) or clinically (excessive urination) and not etiologically, and therefore it is normal to have more than one cause for them. The word is used as an opposition to homogeneous, meaning that given a group of patients, the disease is the same for all of them. When a condition is heterogeneous, it is normally divided in endotypes. An endotype is a subtype of a condition, which is defined by a distinct functional or pathobiological