Ichthyosis 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. 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
Supernumerary body part considered to have lost much or all of their original function through evolution. These body parts can be classed as additional to the required functioning of the body. In human anatomy the vermiform appendix is sometimes classed as a vestigial remnant. Prosthesis is an artificial extension that replaces a body part, and cybernetics is the study of computer technology in relation to organisms which can include replacement or additional body parts. Body integrity identity disorder (BIID) is a psychiatric disorder in which a person thinks that they have one or more additional limbs than they should, despite having two arms