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Muir–Torre syndrome (MTS) is a rare hereditary, autosomal dominant cancer syndrome that is thought to be a subtype of HNPCC. Individuals are prone to develop cancers of the colon, breast, and genitourinary tract, and skin lesions, such as keratoacanthomas and sebaceous tumors. The genes affected are MLH1, MSH2, and more recently, MSH6, and are involved in DNA mismatch repair. == Symptoms == Muir-Torre Syndrome is characterized by both: # At least a single sebaceous gland tumor (either an adenoma, an epithelioma, or a carcinoma) # A minimum of one internal malignancy The Amsterdam criteria are frequently used to diagnose Lynch syndrome and Muir–Torre syndrome. They include the following: * 3 or more relatives with an HNPCC-associated cancer (i.e., colorectal, cancer of the endometrium, small bowel, ureter, or renal pelvis) * 2 or more successive generations affected by cancer * 1 or more persons with cancer is a first-degree relative of the other 2, at least 1 case of colorectal cancer younger than age 50 years, a diagnosis of familial adenomatous polyposis has been excluded, tumors are verified by histologic examination Muir-Torre Syndrome is a genetic condition. Mutations in MLH1 and MSH2 are linked with the disease. These genes code for DNA mismatch repair genes, and mutations increase the risk of developing cancerous qualities. Many patients who have sebaceous neoplasms with mutations in MSH2 and MLH1 do not in fact have Muir-Torre Syndrome. The Mayo Muir-Torre risk score was devised to improve the positive predictive value of immunohistochemistry and reduce the false positive rate.〔Roberts ME, Riegert-Johnson DL, Thomas BC, et al. A clinical scoring system to identify patients with sebaceous neoplasms at risk for the Muir-Torre variant of Lynch syndrome. Genet Med. 2014;16:711-16 doi:10.1038/gim.2014.19〕〔Roberts ME, Riegert-Johnson DL, Thomas BC, et al. Screening for Muir-Torre syndrome using mismatch repair protein immunohisochemistry of sebaceous neoplasms. J Genet Counsel. 2013;22:393-405. DOI 10.1007/s10897-012-9552-4〕 The Mayo Muir-Torre Risk score assigns points based several characteristics. A score of 2 or greater has a high positive predictive value of Muir–Torre syndrome. A score of 1 or lower is less likely to be Muir–Torre syndrome.〔 Age of onset of first sebaceous neoplasm: <60 years = 1 point, otherwise 0 points Total number of sebaceous neoplasms: 1 = 0 points, >2 = 2 points. Personal history of Lynch related cancers: No = 0 points, Yes = 1 point Family history of Lynch-related cancer: No = 0 points, Yes = 1 point The most common internal malignancies associated with Muir–Torre syndrome are: Colorectal (56%), Urogenital (22%), Small Intestine (4%), and Breast (4%). A variety of other internal malignancies have been reported.〔Akhtar S, Oza KK, Khan SA, et al. Muir-Torre syndrome: a case report of a patient with concurrent jejunal and ureteral cancer and a review of the literature. J Am Acad Dermatol. 1999;41:681-6.〕 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「Muir–Torre syndrome」の詳細全文を読む スポンサード リンク
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