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Costello syndrome, also called faciocutaneoskeletal syndrome or FCS syndrome, is a rare genetic disorder that affects many parts of the body. It is characterized by delayed development and mental retardation, distinctive facial features, unusually flexible joints, and loose folds of extra skin, especially on the hands and feet.〔James, William; Berger, Timothy; Elston, Dirk (2005). ''Andrews' Diseases of the Skin: Clinical Dermatology''. (10th ed.). Saunders. ISBN 0-7216-2921-0.〕 Heart abnormalities are common, including a very fast heartbeat (tachycardia), structural heart defects, and overgrowth of the heart muscle (hypertrophic cardiomyopathy). Infants with Costello syndrome may be large at birth, but grow more slowly than other children and have difficulty feeding. Later in life, people with this condition have relatively short stature and many have reduced levels of growth hormones. It is a RASopathy. Beginning in early childhood, people with Costello syndrome have an increased risk of developing certain cancerous and noncancerous tumors. Small growths called papillomas are the most common noncancerous tumors seen with this condition. They usually develop around the nose and mouth or near the anus. The most frequent cancerous tumor associated with Costello syndrome is a soft tissue tumor called a rhabdomyosarcoma. Other cancers also have been reported in children and adolescents with this disorder, including a tumor that arises in developing nerve cells (neuroblastoma) and a form of bladder cancer (transitional cell carcinoma). Costello Syndrome was discovered by Dr Jack Costello, a New Zealand Paediatrician in 1977.〔http://costellokids.com/cs_description/about.htm〕 He is credited with first reporting the syndrome in the Australian Paediatric Journal, Volume 13, No.2 in 1977. ==Genetics== Costello syndrome is caused by any of at least five different mutations in the ''HRAS'' gene on chromosome 11. This gene provides instructions for making a protein, H-Ras, that helps control cell growth and division. Mutations that cause Costello syndrome lead to the production of an H-Ras protein that is permanently active. Instead of triggering cell growth in response to particular signals from outside the cell, the overactive protein directs cells to grow and divide constantly. This unchecked cell division may predispose sufferers to the development of benign and malignant tumors. It remains unclear how mutations in ''HRAS'' cause other features of Costello syndrome, but many of the signs and symptoms may result from cell overgrowth and abnormal cell division. ''HRAS'' is a proto-oncogene in which somatic mutations in healthy people can contribute to cancer. Whereas children with Costello syndrome typically have a mutation in ''HRAS'' in every cell of their bodies, an otherwise healthy person with a tumor caused in part by ''HRAS'' mutation will only have mutant ''HRAS'' within the tumor. The test for the mutation in cancer tumors can also be used to test children for Costello syndrome. Costello syndrome is inherited in an autosomal dominant manner, which means one copy of the altered gene is sufficient to cause the disorder. Almost all cases have resulted from new mutations, and occur in people with no history of the disorder in their family. This condition is rare; as of 20 April 2007, 200 to 300 cases have been reported worldwide. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Costello syndrome」の詳細全文を読む スポンサード リンク
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