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Multiple endocrine neoplasia 1 and 2 (MEN1 and MEN2) are rare disorders of the endocrine system. A comparison of these syndromes and approach to management.<\/p>\n
MEN syndrome describes a group of autosomal dominant inherited disorders<\/strong> characterized by the presence of tumors involving \u22652 endocrine organs<\/strong>, which occur in either a synchronous or metachronous<\/u> fashion.<\/p>\n MEN1 is a tumor suppressor gene<\/strong> which is located on chromosome 11q13. <\/strong>This gene consists of exon sequences which encodes a 610 amino acid protein known as Menin. Menin is responsible for various intracellular processes including the regulation of transcription<\/strong>, genome stability<\/strong>, cell division<\/strong>, and proliferation<\/strong>.<\/p>\n An error in inheritance i.e., a germ-line mutation predisposes involved tissues to tumor formation. First-degree relatives of an affected individual who comes to medical attention (proband) have a 50% chance of developing MEN1.<\/p>\n The usual endocrine glands involved in MEN1 include parathyroid hyperplasia (or adenoma), pituitary adenomas, pancreatic neuroendocrine tumors.<\/p>\n This can easily be remembered by the mnemonic PPP (Parathyroid, Pituitary and Pancreas). See Table 1 for additional features of this syndrome.<\/p>\n<\/blockquote>\n MEN2 is an autosomal dominant inherited disorder<\/strong> characterized by multiple endocrine organ involvement principally of neural crest origin.<\/strong><\/p>\n Mutation of the \u00a0REarranged during Transfection<\/strong> (RET) proto-oncogene (\u00a0expressed by cells of the neural crest, branchial arch, and urogenital system) is responsible for MEN2. The \u00a0RET gene located on \u00a0located on chromosome 10q11.2 and encodes the receptors of the tyrosine kinase family. <\/strong>Indeed, constitutive activation <\/strong>of this receptor and consequent downstream signaling result in unrestricted cell growth and proliferation.<\/p>\n Gain-of-function mutations of RET proto-oncogene<\/strong> result in tumorigenesis in these organs. Thus patients with MEN2A, MEN2B and familial medullary thyroid cancer have underlying germ-line mutations involving the RET proto-oncogene.<\/p>\n<\/blockquote>\n See table 1 for the features of MEN2 A and B.<\/p>\n Should patients with presumed sporadic Medullary thyroid cancer undergo genetic testing?<\/strong><\/p>\n Yes, approximately 50 % of patients with sporadic MTC have somatic RET mutations<\/p>\nWhat is Multiple Endocrine Neoplasia 1 (MEN1)?<\/h2>\n
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When should you consider screening for MEN1 syndrome? (Any)<\/h3>\n
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A patient with suspected MEN1 syndrome presents with primary hyperparathyroidism. Which additional tests are required?<\/h3>\n
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What is Multiple Endocrine Neoplasia 2 (MEN2)?<\/h2>\n
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Comparison of MEN1 and MEN2<\/h2>\n\n
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<\/a>Comparison of MEN1 and MEN2. Mikael H\u00e4ggstr\u00f6m, CC0, via Wikimedia Commons<\/p>\n