What are the genetic changes related to lamellar ichthyosis ?
Mutations in one of many genes can cause lamellar ichthyosis. These genes provide instructions for making proteins that are found in the outermost layer of the skin (the epidermis). The skin abnormalities associated with lamellar ichthyosis disrupt the normal formation of the epidermis, resulting in impaired regulation of body temperature, water retention, and resistance to infections.  Mutations in the TGM1 gene are responsible for approximately 90 percent of cases of lamellar ichthyosis. The TGM1 gene provides instructions for making an enzyme called transglutaminase 1. This enzyme is involved in the formation of the cornified cell envelope, which is a structure that surrounds skin cells and helps form a protective barrier between the body and its environment. TGM1 gene mutations lead to severely reduced or absent enzyme production, which prevents the formation of the cornified cell envelope.  Mutations in other genes associated with lamellar ichthyosis are each responsible for only a small percentage of cases. In some people with lamellar ichthyosis, the cause of the disorder is unknown. Researchers have identified multiple chromosome regions that contain genes that may be associated with lamellar ichthyosis, although the specific genes have not been identified.