Abstract: Objective　IL-12Rβ1 deficiency is a rare immunodeficiency syndrome caused by biallelic mutations in IL12RB1. This study aims to present the clinical features and genetic characteristics of two Chinese children who presented IL12RB1 mutation. Methods　Mutation analyses were done by sequencing and DNA was isolated from peripheral blood samples. We also present the clinical features and review the literature. Results　Two children were boys of 11 months and 13 months old. They were vaccinated with BCG after birth. The ipsilateral axillary lymph nodes were found 3 months after vaccination. The pathogen examination showed the growth of acid-fast bacilli. Both denied the history of tuberculosis exposure. The results of gene analysis showed IL-12RB1 complex heterozygous gene mutations，which were c.1561C＞T，p.R521X；c.632G＞C，p.R211P；c.339-340 del CT，p.L113Lfs*15，and c.1791+2T＞G. Among them，c.339-340 del CT，p.L113Lfs*15 had not been reported before. Conclusion　For children who have infective dissemination after BCG vaccination，primary immunodeficiency gene detection should be performed. The identification of related gene mutations can provide a basis for early treatment and genetic counseling.

Key words: disseminated BCG infection, IL-12RB1 gene, Mendelian susceptibility to mycobacterial disease, gene mutation

摘要： 目的　研究白细胞介素12受体B1基因（IL-12RB1）突变所致孟德尔遗传易感分枝杆菌病的基因资料及临床特点，提高对该病的认识。方法　检测2016—2018年中国医学科学院北京协和医院就诊的2例播散性卡介苗感染患儿基因并分析结果，同时总结患儿的临床资料。结果　2例患儿分别为11月龄和13月龄男性儿童，均于出生后接种卡介苗，接种后3个月出现同侧腋下淋巴结肿大，病原学检查提示抗酸杆菌生长。均否认结核病接触史。基因检测分析结果显示2例患儿均为IL-12RB1复合杂合基因突变，分别为c.1561C＞T，p.R521X；c.632G＞C，p.R211P；c.339-340 del CT，p.L113Lfs*15和c.1791+2T＞G。其中c.339-340 del CT，p.L113Lfs*15未见报道，是新突变。结论　对于接种卡介苗后出现感染性播散的患儿，应进行原发性免疫缺陷基因检测，相关基因突变的识别，可为早期治疗及遗传咨询提供依据。

关键词: 播散性卡介苗感染, IL-12RB1基因, 孟德尔遗传易感分枝杆菌病, 基因突变