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目的探讨1例X连锁多内分泌腺病、肠病伴免疫失调综合征(immune dysregulation,polyendocrinopathy,enteropathy,X-linked syndrome,IPEX)患儿FOXP3基因变异、蛋白表达水平、免疫表型及临床特征。方法对1例表现为早发性顽固性腹泻、自身免疫现象、内分泌功能异常、生长发育落后、IgE增高的疑似IPEX男性患儿外周血单个核细胞采用流式细胞仪检测CD4+CD25+FOXP3+调节性T细胞比例和FOXP3蛋白表达,PCR法进行外周血FOXP3基因扩增及测序、比对分析,排除多态性以确定致病突变。结果该患儿CD4+CD25+FOXP3+调节性T细胞比例较正常对照明显降低,FOXP3蛋白表达量与正常对照无显著差异。经基因分析确诊为IPEX,其FOXP3基因第8号外显子末位碱基错义突变(G>A),导致FOXP3蛋白323位氨基酸由谷氨酸替换为赖氨酸(Glu323Lys),突变基因的转录产物中除了一部分为错义突变外,还形成了多种异常拼接体,部分为缺失第8号外显子,部分同时缺失7、8号外显子,另有部分完全或部分缺失5号外显子及部分11号外显子。患儿母亲为该突变的携带者。结论通过临床、免疫学筛查、基因分析及流式细胞术,确诊1例发生FOXP3多种不同异常拼接及错义突变的IPEX患儿,为此前未报到的新发突变,对早发顽固性腹泻、湿疹、内分泌功能异常伴自身免疫现象及不明肾脏损害婴幼儿,应考虑IPEX可能并进行FOXP3基因分析以最终确诊。
Objective To investigate the FOXP3 gene mutation, protein expression, immunophenotype and clinical features in one case of X-linked polycnologism and enteropathy (X-linked syndrome, IPEX). Methods One case of peripheral blood mononuclear cells from suspected IPEX male children with early-onset intractable diarrhea, autoimmunity, abnormal endocrine function, poor growth and development, and elevated IgE were examined by flow cytometry for the regulation of CD4 + CD25 + FOXP3 + T cell ratio and FOXP3 protein expression, PCR method of peripheral blood FOXP3 gene amplification and sequencing, comparison and analysis, excluding polymorphisms to determine pathogenic mutations. Results The percentage of CD4 + CD25 + FOXP3 + regulatory T cells in this group was significantly lower than that in the normal control group. FOXP3 protein expression was not significantly different from the normal control. It was identified as IPEX by gene analysis. The base missense mutation of exon 8 of FOXP3 gene (G> A) resulted in the substitution of glutamic acid at position 323 of the FOXP3 protein with lysine (Glu323Lys) In addition to some missense mutations in transcription products, but also formed a variety of abnormal splicing body, part of the deletion of exon 8, part of both exon 7 and exon 8, and some complete or partial deletion of exon 5 And some 11 exons. The mother of the child is the carrier of the mutation. Conclusions One case of IPEX with multiple abnormal splicing and missense mutations in FOXP3 was confirmed by clinical and immunological screening, gene analysis and flow cytometry. It was a new mutation that had not been reported before, Diarrhea, eczema, endocrine dysfunction with autoimmune phenomena, and kidney damage to unknown infants and young children, consider IPEX may be the FOXP3 gene analysis and the final diagnosis.