支气管哮喘患儿PTEN基因突变分析

Analysis of Phosphatase and Tensin Homolog Deleted on Chromosome 10 Gene Mutation in Children with Bronchial Asthma

目的探讨10号染色体上磷酸酶与张力蛋白同源缺失的基因(PTEN)与儿童支气管哮喘(哮喘)的相关性及其与嗜酸性粒细胞(EOS)的关系,为哮喘的发病机制及治疗提供理论依据。方法 30例哮喘复发患儿(临床缓解期)作为哮喘组,30例健康儿童设为健康对照组,2组儿童均于清晨空腹留取外周静脉血1 mL,制备血涂片后提取全基因组DNA,应用聚合酶链反应及克隆、基因测序等方法分析2组儿童PTEN基因第5、第8外显子基因型。并于高倍镜下进行其外周血EOS计数。结果哮喘组患儿PTEN基因第8内含子(intron 8)发现突变,突变率为86.7%(26/30例),健康对照组未发现基因突变。哮喘组患儿外周血EOS计数明显高于健康对照组,差异有统计学意义(P<0.001);发生基因突变的哮喘患儿外周血EOS计数高于无突变的哮喘儿童,差异有统计学意义(P<0.05)。结论 PTEN基因在哮喘儿童中存在突变,可能通过影响RNA的选择性剪切及抑制EOS的活化和趋化在哮喘的发病中发挥作用。

Objective To explore the correlation between phosphatase and tensin homolog deleted on chromosome 10 （PTEN） and chil- dren with bronchial asthma（ asthma）, and to investigate the relationship between PTEN and the number of eosinophils （EOS） ,which may pro- vide some theoretical basis for the pathogenesis and treatment of asthma. Methods Thirty children with asthma （ clinical paracmasis） were enrolled as asthmatic group. Meanwhile ,30 healthy children were selected as healthy control group, and 1 mL peripheral vein blood was drawn from each child with empty stomach in the early morning. Each blood sample was extracted for genomic DNA after preparation of blood smear. The genotypes of exon 5 and exon 8 of PTEN genc were detected by means of polymerase chain reaction, gene clone and DNA sequencing and analysis. The count of peripheral blood EOS was determined under high power lens. Results There were mutations at imron 8 of PTEN gene in asthmatic group, and the mutation rate was 86.7% （26/30 cases）. No mutation was found in healthy control group. The count of peripheral blood EOS in asthmatic group was obviously higher than that in healthy control group（ P 〈 0. 001 ）. The counts of peripheral blood EOS of asthmatic children with mutations were higher than those of asthmatic children without mutations （ P 〈 0.05 ）. Conclusion PTEN mutation may play a subordinate role in the pathogenesis of asthma by influencing the RNA alternative splicing and inhibiting activation and chemotaxis of EOS.