【摘要】 目的通过对X连锁无丙种球蛋白血症(XLA)患儿Bruton’s酪氨酸激酶(BTK)基因变异和临床特征的分析,提高临床医师对XLA的认识。方法收集2008年2月至2008年12月在我院住院的10例XLA患儿外周静脉血,采用RT-PCR方法扩增BTK cDNA,PCR产物直接双向测序。突变结果经DNA相应外显子部位扩增、测序进一步证实。结果10例XLA患儿中7例患儿发现有BTK基因突变。6例位于编码区,1例位于内含子区。突变类型包括错义突变3例,无义突变1例,缺失2例和内含子剪接位点突变1例。其中5例(F583L,135Nfs177X,R123X,C502Y,IVS9+2T>C)为首次报道的新型突变。进行基因分析的6例XLA患儿母亲均为携带者。结论BTK基因分析有助于XLA患儿的进一步明确诊断,而且有利于发现携带者和进行遗传咨询。更多还原

【Abstract】 Objective To realize the feature of gene mutation of X-linked agammaglobulinemia (XLA) in Chinese children. Methods Ten patients from 10 unrelated Chinese families were included in the study. All patients were male and diagnosed as having XLA. The diagnosis of XLA was based on the absence or very low levels of B cells in the blood,low levels of immunoglobulins and a history of recurrent bacterial infections. To identify mutations in the coding region of (Bruton’s tyrosine kinase) BTK,cDNA was prepared by a reverse transcriptase PCR reaction from peripheral blood mononuclear cells. The amplified products were directly sequenced by cycle sequencing. The detected mutation was confirmed on genomic DNA templates. Results Seven different mutations were identified in the 7 patients and no mutation was found in the other 3 patients. Six mutations located at BTK coding region and one mutation located at splice site. The types of mutation included three missense mutations,one nonsense mutation,two deletion mutations,and a splice site mutation. Five of the seven mutations (F583L,135Nfs177X,R123X,C502Y,IVS9+2T>C) are novel mutation types which have not been reported. The spot mutation in splice site of intron 9 (IVS9+2T>C) resulted in exon 9 skipping. Six of seven mothers were analyzed and all of them were carriers. Conclusion The results of this study further support the notion that molecular genetic testing represents an important tool for definitive and early diagnosis of XLA and may allow accurate carrier detection and prenatal diagnosis. Those patients without mutation identified in the BTK gene may require a further genetic analysis on autosomal recessive bases.更多还原