Abstract: Objective To analyze the gene mutations of three male children clinically diagnosed with X-linked severe combined deficiency syndrome(X-SCID), in order to provide evidence for genetic counseling and prenatal diagnosis. Methods Interleukin-2 receptor gene (IL2RG) mutation was detected by whole exome sequencing and direct sequencing in children and family members, and prenatal diagnosis was performed in one of the families. Results The mutation of c.202G>A(p.Glu68Lys)was detected in the IL2RG gene in family 1and family 2,and the mutation of c.676C > T (p.Arg226Cys) was found in IL2RG gene of family 3.The mother of the proband found the fetus as female through prenatal diagnosis, carrying the same pathogenic gene with the proband, but this couple chose to continue the pregnancy. Conclusion Totally 3 cases of X-SCID are diagnosed by IL2RG gene detection, and successful prenatal diagnosis is given to one X-SCID family, thereby giving guidance for pregnancy of family 3.

Key words: X-linked severe combined immunodeficiency, IL2RG gene, gene mutation

摘要： 目的 对3个临床拟诊X-连锁严重联合免疫缺陷综合征(X-SCID)患儿及父母进行基因突变分析,为遗传咨询及产前诊断提供依据。方法 应用高通量测序和直接测序的方法对患儿及家系成员进行白细胞介素-2受体基因(IL2RG)突变检测,分析IL2RG基因外显子区及与外显子交界的部分内含子区域DNA序列改变情况,寻找可能的致病突变位点,并对其中一个家系进行羊水细胞产前诊断。结果 家系1、家系2患儿IL2RG基因检测到c.202G>A(p.Glu68Lys)突变,家系3患儿IL2RG基因检测到c.676C>T(p.Arg226Cys)突变,患儿母亲均为相应突变携带者。家系3先证者母亲进行产前诊断胎儿为女性,携带与先证者相同的致病基因,夫妇双方选择继续妊娠。结论 通过IL2RG基因检测明确诊断3例X-SCID患儿,并成功对1个X-SCID家系进行产前诊断,指导家系3夫妇选择妊娠。

关键词: X-连锁严重联合免疫缺陷综合征, IL2RG基因, 基因突变