儿童噬血细胞综合征临床及基因突变筛查研究

Gene mutation associated with hemophagocytic lymphohistiocytosis in children

目的研究SH2D1A、XIAP、PRF1、UNC13D、STX11、STXBP2、RAB27A、AP3B1、LYST及ITK等10种儿童噬血细胞综合征(HLH)相关突变基因在HLH分布情况及相关临床特点。方法收集2012年7月-2015年11月期间按照国际组织细胞协会HLH-2004标准确诊为HLH的37例患儿的血液样本并行基因测序,对测序结果进行突变位点分析。结果37名HLH患儿的中位年龄为2.6岁,检出基因突变组(22例)与未检出基因突变组(15例)中位年龄分别为2.09岁、2.67岁,差异无统计学意义(P>0.05)。22例患儿检测出基因突变,均为杂合突变未见纯合突变。UNC13D突变例数最多(50%)以内含子剪切位点突变为主(38%),同时存在错义突变和移码突变。多位点突变与单一位点突变、无突变组在发病年龄、粒细胞及血小板减少程度、NK细胞数量上无明显差异。70.3%HLH患儿同时合并有EB病毒感染。4例复发、1例初诊时死亡患儿均来源于基因突变组,其中4例存在EB病毒感染,1例疾病初期无EB病毒感染,而复发时检测出EB病毒阳性。结论 UNC13D突变在中国人群的HLH较多,基因突变与患儿年龄、病情严重程度无明显相关性。

Objectives To detect gene mutation associated with hemophagocytic lymphohistiocytosis(HLH)and toidentify mutation spectrum and clinical feature in HLH in children.Methods Thirty-seven(37)pediatric patients diagnosedwith HLH according to2004clinical and laboratory criteria were enrolled from July2012to November2015.Nucleotidesequences of all exons and their flanking intronic sequences of ten genes associated with HLH were amplified with PCR followedby direct sequencing.Point mutation analysis was performed after the direct sequencing.Results The median age of all the37patients was2.6years.The median ages of patients with gene mutation(n=22)and without gene mutation(n=15)was2.09years and2.67years,without statistical significance.Twenty-two patients were identified with gene mutations.All of them wereheterozygous.UNC13D mutation(50%)is of the highest frequency in the above genes.The splicing mutations(38%)were themain type of UNC13D mutations,and missense mutations or frame-shift mutations were also found.There was no statisticaldifference in ages of onset and laboratory data of neutrophils,thrombocytes,NK cell activities within the three groups:multi-sitemutations,single-site mutations and no mutations.EBV infection was detected in70.3%patients.In mutation group,one patientdied when he was in the period of inducing remission,and four patients were relapsed.Among them four patients were infectedwith EBV and one patients was negative at the onset while positive in recurrence.Conclusions UNC13D was the predominantcausative gene in the Chinese population according our data.There was no significant relevance between age of onset,severity ofdisease and gene mutations.Attention should be paid to a patient with HLH gene mutation infected by EBV,which it might meana poor prognosis.