Ahmed Fahad W., Majeed Muhammad S., Kirresh Omar
King Faisal Specialist Hospital and Research Center Madinah
Royal Sussex County Hospital, Brighton
Multiple endocrine neoplasia (MEN) constitutes a group of autosomal dominant disorders characterized by a broad spectrum of endocrine and nonendocrine diseases. Depending on the clinical presentations and genetic mutation, MEN is divided into different types. The most common syndrome is MEN type 1 (MEN1), characterized by primary hyperparathyroidism secondary to parathyroid gland hyperplasia, pituitary adenoma, and pancreatic neuroendocrine tumors. MEN type 2 (MEN2) is less common, divided into MEN2A and MEN2B, depending on clinical phenotype. MEN2A is characterized by medullary thyroid cancer, pheochromocytoma, and primary hyperparathyroidism; MEN2B is characterized by medullary thyroid cancer, pheochromocytoma, marfanoid features, and neuromas of lips, tongue, and colon. MEN type 4 (MEN4) is the most recently identified type of MEN. Although it shares a similar phenotype spectrum to MEN1, MEN4 is rare. The difference between MEN1 and MEN4 lies in the germline gene mutation: in MEN1, there is a mutation of the MEN1 gene; in MEN4, there is a mutation in the cyclin-dependent kinase inhibitor 1B gene (). Hyperparathyroidism is the primary clinical manifestation of MEN4, followed by pituitary adenomas. Less frequently, MEN4 may be associated with tumors of the adrenals, kidneys, and reproductive organs. Compared with other types of MEN, such as MEN1, MEN4 is far less reported in the literature.
多发性内分泌腺瘤病（MEN）是一组常染色体显性遗传病，其特征为广泛的内分泌和非内分泌疾病。根据临床表现和基因突变情况，MEN可分为不同类型。最常见的综合征是MEN1型（MEN1），其特征为甲状旁腺增生继发的原发性甲状旁腺功能亢进、垂体腺瘤和胰腺神经内分泌肿瘤。MEN2型（MEN2）较不常见，根据临床表型分为MEN2A和MEN2B。MEN2A的特征为甲状腺髓样癌、嗜铬细胞瘤和原发性甲状旁腺功能亢进；MEN2B的特征为甲状腺髓样癌、嗜铬细胞瘤、类马凡氏体型特征以及唇部、舌部和结肠的神经瘤。MEN4型（MEN4）是最近发现的MEN类型。尽管它与MEN1具有相似的表型谱，但MEN4很罕见。MEN1和MEN4的区别在于种系基因突变：在MEN1中，存在MEN1基因突变；在MEN4中，细胞周期蛋白依赖性激酶抑制剂1B基因发生突变。甲状旁腺功能亢进是MEN4的主要临床表现，其次是垂体腺瘤。MEN4较少与肾上腺、肾脏和生殖器官的肿瘤相关。与其他类型的MEN（如MEN1）相比，MEN4在文献中的报道要少得多。
