X连锁无丙种球蛋白血症的基因诊断  

Gene diagnosis of X-linked agammaglobulinemia

作　　者：王晓川[1] 王莹[1] 金兼弘和 宫脇利男 俞晔珩[1] 

机构地区：[1]复旦大学附属儿科医院临床免疫研究室复旦大学上海医学院儿科学系,上海200032 [2]日本富山医科药科大学医学部小儿科

出　　处：《中华儿科杂志》2005年第6期449-452,共4页Chinese Journal of Pediatrics

摘　　要：目的研究我国X连锁无丙种球蛋白血症(XLA)患者Bruton′s酪氨酸激酶(BTK)基因的突变类型。方法采用逆转录-聚合酶链反应(RT-PCR),获得7例XLA患者cDNA。使用8对不同引物分2步扩增BTKcDNA,PCR产物测序。突变结果通过对DNA外显子相应部位扩增、测序证实。对其中4例母亲进行基因分析。结果7例患者的基因突变均位于BTK基因的编码区,3例在BTK的血小板-白细胞C激酶底物同源区,2例位于酪氨酸激酶区,其他2例分别位于Src同源区2和Src同源区3。突变包括:错义突变、无义突变、重复序列和片段缺失。除错义突变引起单一BTK氨基酸改变外,突变还分别造成终止密码子形成和阅读框架移位。其中4例为未见报道的新突变。进行基因分析的4例母亲中,3例为携带者。结论本组患者临床表现为典型XLA,检测出的7种突变均位于BTK基因编码区,其中4种是未见报道的新突变。XLA可以通过基因分析进行确诊以区别与其他低丙种球蛋白血症。Objective X-linked agammaglobulinemia (XLA) is the most common disorder among primary immunodeficiency diseases, which is caused by mutations in the cytoplasmic Bruton′s tyrosine kinase (BTK) gene, characterized by lack of mature, circulating B lymphocytes, hypogammaglobulinemia, and recurrent bacterial infections. Mutations in BTK are highly diverse. In this study, genetic analysis was performed on BTK to realize the feature of gene mutation of XLA in Mainland of China. Methods Seven patients from 7 different families were enrolled in the analysis. RT-PCR was employed to reverse transcript total RNA and 8 couples of primers were designed for PCR. PCR products were sequenced and the mutation sites were identified. Results Seven completely different mutations were identified in the 7 patients. All the 7 mutations located at BTK coding region. Three of the 7 mutations were located in pleckstrin homology functional area, 2 mutations located in BTK area, and in other 2 cases at Src homology 2 and Src homology 3 regions, respectively. The mutations in 2 of 7 cases were in exon 18, and the others were in exon 2, 5, 6, 8 and 10, respectively. The types of mutation included 3 missense (L11P, I590F and Y591S), two nonsense (W281X, and Q234X) mutations resulting in premature stop codons. A 10-base pair nucleotides duplicated insertion located between the nucleotide 596 and 597 resulting in frameshift, and a 8 base pair deletion at the nucleotide position 472 resulting in frameshift. Four of the 7 mutations are novel mutation types and have not been reported. Four of 7 mothers were analyzed, 3 of them were carrier and 1 was normal. Conclusion The patients enrolled in this study had classical clinical features of XLA. All the 7 identified mutations located at BTK coding region and 4 of them were novel mutations. Genetic analysis can be used for diagnosis of XLA and distinguish it from other hypogammaglobulinemia.

关 键 词：X连锁无丙种球蛋白血症 基因诊断 逆转录-聚合酶链反应 低丙种球蛋白血症 酪氨酸激酶 Bruton 基因分析 cDNA 错义突变 PCR产物 BTK基因 终止密码子 基因编码区 XLA 同源区 突变类型 PCR) 基因突变 无义突变 重复序列 临床表现 

分 类 号：R725.9[医药卫生—儿科]