Wiskott-Aldrich综合征10例临床特点与实验室诊断分析

Clinical features and molecular analysis of ten patients with Wiskott-Aldrich syndrome in China

目的探讨10例Wiskott-Aldrich综合征(WAS)患儿的临床及分子特点。方法总结10例拟诊WAS患儿临床资料,包括血常规、免疫功能、骨髓常规和扫描电镜检查及临床表型评分。流式细胞术(FCM)检测10例患儿外周血单个核细胞(PBMC)中WAS蛋白(WASP)表达。PCR扩增WASP基因序列并直接双向测序分析9例患儿及其亲属突变情况。结果本组均男性,多以自幼大便带血丝及皮肤瘀点瘀斑起病。均有血小板减少伴小血小板,湿疹和免疫缺陷表现。临床表型评分3例评5分,3例评4分,4例评3分。具有阳性家族史患儿临床诊断年龄明显早于无家族史者。多数患儿IgA(8/9)、IgE(8/9)和IgG(7/9)升高,除6例CD4^+T比例下降(6/9),其余患儿淋巴细胞亚群分类正常。1例淋巴细胞增殖功能降低(1/3)。骨髓常规缺乏特征性改变。5例患儿淋巴细胞扫描电镜(SEM)均可见典型微绒毛异常。10例患儿WASP均为阴性,9例行WASP基因分析发现7种不同突变,3例为新型突变(168 C>A,T45 K;747-748 del T,I 238 Fs X260;253 Ins A,C73X)。8例位于编码区,1例位于内含子。4例突变位于EVH1区,2例BR区,1例VCA区,1例GBD区。突变类型包括无义突变4例(2例155 C>T,R 41 X;2例665 C>T,R 211 X),错义突变2例(168 C>A,T45 K~*;1487G>A,D485N/5'剪切),缺失突变1例(747-748 del T,I 238 Fs X260~*),拼接位点突变1例(Ivs9+2 T>C),插入突变1例(253 Ins A,C73X~*)。8例患儿母亲为突变携带者。除预防性抗生素及静注丙球(IVIG),3例接受干细胞移植,移植后2例正常表达WASP,1例死于巨细胞病毒(CMV)所致的肺间质性病变。结论早发持续血小板减少伴血小板体积减少的男性患儿应怀疑WAS及相关疾病、WAS蛋白检测和基因分析是明确诊断的重要手段。基因分析还有利于发现携带者和进行遗传咨询。干细胞移植是目前根治WAS,尤其是重症患儿最有效的方法。

To explore the clinical and molecular features of ten Chinese patients with Wiskott-Aldrich syndrome（WAS）.Clinical data of ten boy patients was analyzed,including clinical manifestations,scoring of the phenotype,peripheral blood,immunological functions, bone marrow examination,and scanning electron microscope（SEM）.And then,flow cytometry was used to analyze the WAS protein（WASP） expression in peripheral blood mononuclear cells（PBMCs） of ten patients;PCR direct sequence analysis of WASP gene was performed in nine unrelated Chinese families.Most patients had hematorrhea and petechiae as initial symptom in early lifetime;all ten patients presented as classic WAS phenotype,while none had the X-linked thrombocytopenia（XLT） phenotype.Three patients scored 5 had autoimmune disorders or tumor,including autoimmune hemolysis（AIHA） in two patients and retinoblastoma in one patient.Three patients scored 4 due to severe eczema and infections,while the other four patients scored 3.All patients had the presentation of persistent thrombocytopenia,decreased mean platelet volume（MPV）,among them,four patients had eosinophilia.Most patients showed elevated IgA（8/9）,IgE（8/9）,and lgG（7/9）.Six patients showed decreased CD4＋ T lymphocyte（6/9）.Five WAS patients had typical SEM anomalies on lymphocytes.Deftcient WASP expressions were exclusively demonstrated in all patients.Nine of the ten patients had 7 different mutations including 4 nonsense mutations（155 CT,R 41 X in 2 cases;665 CT,R 211 X in 2 cases）,2 missense mutation（168 CA,T 45 K＊;1487GA, D485N/5＇ splice site）,a deletion mutation（747-748 del T,1238 Fs X260＊）,a splice anomaly（Ivs9 ＋2 TC）,and a insertion mutation （253 Ins A,C73X＊）.Three novel mutations were identified and marked with asterisk（＊）;four of seven mutations located in EVH1.Eight of nine mothers were analyzed and all of them were carriers.Three patients received hematopoietic stem cell transplantation（HSCT） and one died from cytomegalovirus pneumonitis.All results suggest that male patients,presenting with hematorrhea and early-onset thrombocytopenia associated with small MPV,should he suspected of WAS.Flow cytometrie analysis of the WASP expression in PBMC and further WASP gene sequence analysis are the keys to prompt diagnosis and finding of carriers.HSCT is currently the mainstay of treatment for WAS,especiallv those with classic WAS phenotype.