Ichthyosis vulgaris Ichthyosis vulgaris Ichthyosis vulgaris (also known as "Autosomal dominant ichthyosis," and "Ichthyosis simplex") is a skin disorder causing dry, scaly skin. It is the most common form of ichthyosis, affecting around 1 in 250 people. For this reason it is known as common ichthyosis. It is usually an autosomal dominant inherited disease (often associated with filaggrin), although a rare non-heritable version called acquired ichthyosis exists. The symptoms of the inherited form of ichthyosis vulgaris are not usually present at birth but generally develop between 3 months and 5 years of age. The symptoms will often improve with age, although they
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