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Multiple endocrine neoplasia type 2B (also known as "MEN2B", "Mucosal neuromata with endocrine tumors", "Multiple endocrine neoplasia type 3", and "Wagenmann–Froboese syndrome") is a genetic disease that causes multiple tumors on the mouth, eyes, and endocrine glands. It is the most severe type of multiple endocrine neoplasia, differentiated by the presence of benign oral and submucosal tumors in addition to endocrine malignancies. It was first described by Wagenmann in 1922, and was first recognized as a syndrome in 1965-1966 by E.D. Williams and D.J. Pollock. MEN 2B typically manifests before a child is 10 years old. Affected individuals tend to be tall and lanky, with an elongated face and protruding, blubbery lips. Benign tumors (neoplasms) develop in the mouth, eyes, and submucosa of almost all organs in the first decade of life. Medullary thyroid cancer almost always occurs, sometimes in infancy. It is often aggressive. Cancer of the adrenal glands (pheochromocytoma) occurs in 50% of cases. A variety of eponyms have been proposed for MEN 2B, such as Williams-Pollock syndrome, Gorlin-Vickers syndrome, and Wagenmann-Froboese syndrome. However, none ever gained sufficient traction to merit continued use, and are no longer used in the medical literature. The prevalence of MEN2B is not well established, but has been derived from other epidemiological considerations as 1 in 600,000 to 1 in 4,000,000. The annual incidence has been estimated at 4 per 100 million per year.〔 - Chapter: ''Multiple Endocrine Neoplasia Type 2B '' by Electron Kebebew, Jessica E. Gosnell and Emily Reiff. Pages 695-701. () This reference quotes a prevalence of 1 in 40,000, but this figure is inconsistent with the same reference's calculated incidence of 4 per 100 million per year for MEN2B.〕 ==Causes== Variations in the RET proto-oncogene cause MEN2B. In recent decades no case of MEN2B has been reported that lacks such a variation. The M918T variant alone is responsible for approximately 95% of cases. All DNA variants that cause MEN2B are thought to enhance signaling through the RET protein, which is a receptor molecule found on cell membranes, whose ligands are part of the transforming growth factor beta signaling system. About half of cases are inherited from a parent as an autosomal dominant trait. The other half appear to be spontaneous mutations,〔 usually arising in the paternal allele, particularly from older fathers.〔 The sex ratio in de novo cases is also uneven: sons are twice as likely to develop MEN 2B as daughters.〔 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「Multiple endocrine neoplasia type 2b」の詳細全文を読む スポンサード リンク
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