RET 基因p.M918T 突变导致多发性内分泌肿瘤-IIb 型1例

多发性内分泌肿瘤-IIb 型(multiple endocrine neoplasia type-IIb，MEN-IIb)是一种罕见的由RET基因突变 引起的常染色体显性遗传病，具有特殊的临床表型，如黏膜神经瘤、类马方综合征体型、甲状腺髓样癌及嗜铬细胞 瘤等。临床医生对此病认识不足，诊断往往延迟。2018 年11 月中南大学湘雅三医院收治了1 例MEN-IIb 患者，该患 者自幼有舌黏膜神经瘤，曾因二尖瓣脱垂及脊柱畸形接受手术治疗，于22 岁时被诊断为甲状腺髓样癌并接受手术治 疗，但直至28 岁发现嗜铬细胞瘤才临床诊断为MEN-IIb。基因检测提示该患者携带一新发RET基因p.M918T杂合突 变。在临床工作中早期识别内分泌系统以外的临床表现并进行RET基因筛查是早期诊断及治疗的关键。

Multiple endocrine neoplasia-IIb with RET gene mutation p.M918T：A case report

Multiple endocrine neoplasia-IIb (MEN-IIb) is a rare hereditary autosomal dominant syndrome caused by mutations in the RET proto-oncogene. It’s characterized by medullary thyroid carcinoma (MTC), pheochromocytoma (PHEO), mucosal neuromas, and Marfanoid habitus. Because of the rarity of MEN-IIb and finiteness of clinical cognition, the majority of the patients suffer a delayed diagnosis. A MEN-IIb patient with the lingual mucosal neuromas since childhood was admitted in the Third Xiangya Hospital of Central South University in November, 2018. He had surgical history of mitral valve prolapse and spinal deformity. He was diagnosed with MTC and PHEO at the age of 22 and 28, respectively, and received surgical treatments. Sequencing of RET gene revealed a de novo heterozygous p.M918T mutation in the patient. Being aware of the unique clinical phenotype and screening of RET gene mutation may lead to the early diagnosis and better long-term outcome for MEN-IIb.