六例X连锁无丙种球蛋白血症患儿BTK基因突变检测及临床分析  

Detection of Bruton＇ s tyrosine kinase gene mutations and clinical analysis of 6 patients with X-linked agammaglobulinemia

作　　者：张晓敏[1] 李虹[2] 李强[1] 高举[1] 石晓青[3] 

机构地区：[1]四川大学华西第二医院儿科血液、免疫科,成都610041 [2]四川大学教育部产科及儿科疾病、出生缺陷重点实验室,成都610041 [3]四川大学儿科,成都610041

出　　处：《中华医学遗传学杂志》2014年第1期29-33,共5页Chinese Journal of Medical Genetics

摘　　要：目的研究Bruton酪氨酸激酶（Bruton＇ s tyrosine kinase, BTK） 基因突变与X连锁无丙种球蛋白血症（X-linked agammaloglobulinemia, XLA）的临床表型的关系。方法收集临床6例反复呼吸道感染并疑诊XLA的患儿病史、家族史、体格检查及辅助检查资料。采集患儿外周静脉血，PCR扩增BTK基因19个外显子及外显子与内含子连接区，PCR产物直接正反向测序并与GenBank中BTK基因序列进行比对确定有无BTK基因突变，及突变碱基和位置，以及相应的突变氨基酸及位点，对其中5例患儿的母亲DNA相应外显子进行基因测序确定是否为BTK基因突变携带者。结果本组6例临床疑诊XLA的患儿均发现有BTK基因编码区突变，其中3例患儿突变发生在BTK基因酪氨酸激酶（the kinase domain，TK）功能区，2例在BTK基因血小板一白细胞C激酶底物同源区（pleckstrin homology，PH），1例在Src同源区2（Src homology2，SH2）。突变类型在6例患儿中3例为错义突变[c．1105C〉T（p．L369F），c．82c〉T（p．R28C），C．1754T〉C（p．V585A）]；2例为无义突变[c．1834C〉T（p．Q612X），c．37C〉T（p．R13X）]；1例为错义及移码复合突变[c．1802—1803TT〉GC（p．F601C）及c．1803—1804insC（p．T602fsX603）]；其中[p．F601C、p．T602fsX603及p．V585A为未报道过的BTK基因新突变。在所检测的5例患儿母亲中有4例证实为BTK基因突变携带者，1例患儿母亲正常。结论通过对6例临床拟诊XLA的患儿进行BTK基因突变检测，证实了患儿XLA的临床诊断，并发现3个新的BTK基因突变。及早进行基因诊断，规律地采用免疫球蛋白进行终身替代治疗可预防及治疗患儿感染、挽救患儿生命，并可发现携带者及进行遗传咨询。Objective To explored the relationship between genotype of Bruton＇s tyrosine kinase （BTK） gene and X-linked agammaglobulinemia （XLA）. Methods Six patients who were clinically suspected as XLA based on immunological results were studied. Peripheral blood samples were collected for DNA extraction. The 19 exons and exon-intron boundaries of the BTK gene were amplified by PCR, and the products were directly sequenced. Results All of the 6 patients were confirmed to have XLA due to the mutations in exons of the BTK gene. Among these, 3 mutations were located in the kinase domain （TK）, 2 were located in pleckstrin homology （PH） domain, and 1 was located in Sre homology （SH2） domain. The mutations have included 3 missense mutations, i. e. , c. 1105C〉T （p. L369F）, c. 82C〉T（p. R28C） and c. 1754T〉C （p. V585A）, 2 nonsense mutations, i. e. , c. 1834C〉T （p. Q612X） and c. 37C〉T （p. R13X）. One patient was found to have complex （missense and nonsense） mutations, i. e. , c. 1802-1803TT〉GC （p. F601C） and c. 1803-1804insC （p. T602fsX603）. There were 3 novel mutations （p. F601C, p. T602fsX603 and p. V585A）. The mothers of 5 patients were also detected with BTK gene mutations, among whom 4 were demonstrated to be carriers and one was normal （her son had p. V585A mutation）. Therefore,p. V585A was a de novo mutation. Conclusion Detection of BTK gene mutation can confirm clinical diagnosis which is critical for patients to take regular immunoglobulin replacement therapy for life. Early genetic diagnosis can also identify carriers and make genetic counseling possible.

关 键 词：X连锁无丙种球蛋白血症 BTK基因 基因突变 

分 类 号：R725.5[医药卫生—儿科]