目的：研究遗传性甲状腺髓样癌（hereditary medullary thyroid carcinoma，HMTC）病人RET基因型和疾病表型的关系。方法：回顾性分析2015年3月至2019年9月间于我院乳腺甲状腺外科诊断为HMTC并行甲状腺癌手术的13例病人。随访截至2021年9月。根据基因检测结果和美国甲状腺协会（American Thyroid Association，ATA）指南对13例病人进行风险评估。研究不同RET基因型的疾病表型，包括生化检测结果和TNM分期以及生化治愈（血清降钙素正常）和临床治愈率。结果：RET基因最高风险突变（M918T位点）、高风险突变（C634Y和C634S位点）和中风险突变（C618G和C611Y位点）的病人分别有1例（7.69%）、6例（46.15%）、6例（46.15%）。其中，1例最高风险突变病人的TNM分期为Ⅳ期;6例高风险突变病人的TNM分期分别为Ⅰ期4例（66.67%），Ⅲ期2例（33.33%）;6例中风险突变病人分期分别为Ⅰ期1例（16.67%），Ⅱ期1例（16.67%），Ⅲ期3例（50%），Ⅳ期1例（16.67%）。关于术前降钙素和癌胚抗原含量，最高风险突变1例病人最高（20 000 ng/L，831.8 μg/L），高风险突变6例病人最低（537.7 ng/L，41.7 μg/L），中风险突变6例病人次之（1 221.4 ng/L，62.3 μg/L）。同样，最高风险突变病人的临床治愈率和生化治愈率较差，高风险突变较好，中风险突变次之。结论：RET基因与ATA风险有关。RET基因高风险突变病人较中风险突变病人具有较高的临床治愈率和生化治愈率。

Objective To investigate the association between RET genotype and disease phenotype in the patients with hereditary medullary thyroid carcinoma (HMTC). Methods A total of 13 patients diagnosed as HMTC and undergoing surgical treatment for thyroid carcinoma in this hospital from March 2015 to September 2019 were analyzed retrospectively with follow-up cutoff at September 2021. The patient risk stratification was performed according to American Thyroid Association (ATA) guidelines. The association between RET genotype and disease phenotype including biochemical results, TNM stage, both biochemical [normal serum calcitonin(CT)] cure and clinical cure was analyzed. Results There were 1 (7.69%) case, 6(46.15%) cases, and 6(46.15%) cases with the highest risk mutation (RET M918T), high-risk mutation (RET C634Y and C634S), and moderate-risk mutation (RET C618G and C611Y), respectively. One case with the highest risk mutation was at TNM stage Ⅳ. There were 4 cases (66.67%) at stageⅠand 2 cases (33.33%) at stage Ⅲ among 6 cases with high-risk mutation. For 6 cases with moderate-risk mutation, stage Ⅰ and stage Ⅱ had 1 case(16.67%) respectively, and stage Ⅲ and stage Ⅳ with 3 cases (50%) and 1 case (16.67%) respectively. The highest preoperative CT and carcinoembryonic antigen were detected in 1 case with highest risk mutations (20 000 ng/L, 831.8 μg/L), and those lower in 6 cases with moderate-risk mutations (1 221.4 ng/L, 62.3 μg/L). The lowest of them were in 6 cases with high-risk mutations (537.7 ng/L, 41.7 μg/L). Similarly, both clinical cure rate and biochemical cure rate were found poorer in the cases with the highest risk mutation, and better in the case with high-risk mutation, and less better in the cases with moderate-risk mutation. Conclusions RET gene could be associated with HMTC risk of ATA. The patients of RET genotype with high-risk mutations would have higher clinical cure rate and biochemical cure rate than the cases with moderate-risk mutations.