Jackson C E, Norum R A
Division of Clinical and Molecular Genetics, Henry Ford Hospital, Detroit, MI 48202.
Henry Ford Hosp Med J. 1992;40(3-4):232-5.
Multiple endocrine neoplasia type 2B (MEN 2B) is similar to MEN 2A in that both autosomal dominant syndromes include medullary thyroid cancers and pheochromocytomas. It is distinct in that MEN 2B patients have much earlier age of onset with more aggressive tumors and mucosal neuromas of the lips and tongue. The neuromas allow ascertainment generally before age 5. Studies of two and three generations of 14 MEN 2B families disclosed close linkage of the MEN 2B gene to DNA markers to which MEN2A had been linked. Multipoint analysis utilizing additional results in three generations of a 15th family have disclosed a peak total lod score of 8.89 at the midpoint between the centromere markers D10Z1 and RBP3 on the long arm (band q11). One recombinant was observed between D10Z1 and MEN2B, but this individual was not recombinant with D10S94. These studies suggest physical proximity of MEN2A and MEN2B but do not establish allelism for the gene(s).
2B型多发性内分泌腺瘤病（MEN 2B）与2A型多发性内分泌腺瘤病（MEN 2A）相似，因为这两种常染色体显性遗传病都包括甲状腺髓样癌和嗜铬细胞瘤。MEN 2B的不同之处在于，MEN 2B患者发病年龄更早，肿瘤侵袭性更强，且嘴唇和舌头有黏膜神经瘤。这些神经瘤通常在5岁前就能被发现。对14个MEN 2B家族的两代和三代成员进行的研究表明，MEN 2B基因与MEN 2A所关联的DNA标记紧密连锁。利用第15个家族三代成员的更多结果进行的多点分析显示，在长臂（q11带）着丝粒标记D10Z1和RBP3之间的中点，最大对数优势总分达到8.89。在D10Z1和MEN2B之间观察到一个重组个体，但该个体与D10S94没有重组。这些研究表明MEN2A和MEN2B在物理位置上相近，但并未确定相关基因的等位性。
