中国CBAVD患者CFTR基因内含子10-11(TAAA)n短串联重复序列检测及意义

The detection and significance of Cystic Fibrosis Transmembrane Conductance Regulator gene IVS10-11(TAAA)n STR in Chinese Congenital Bilateral Absence of the Vas Deferens

目的囊性纤维化跨膜转导子基因(cystic fibrosis transmembrane conductance regulator,CFTR,OMIM602421)突变可以导致先天性双侧输精管缺如(congenital bilateral absence of the vas deferens,CBAVD,OMIM 277180)的发生,既往研究证明:其内含子(IVS)10-11(TAAA)n短串联重复序列(STR)是重要的顺式作用原件,可以与FOXI1转录因子结合,负向调节CFTR基因的表达,当其发生变异,尤其与启动子c.-165G>A联合时可以导致CBAVD的发生,IVS10-11(TAAA)n STR在中国人群中的分布未见相关研究。本研究的目的是探讨中国CBAVD患者CFTR基因IVS10-11(TAAA)n STR和启动子c.-165G>A的变异情况。方法对66例CBAVD患者CFTR基因IVS10-11(TAAA)n STR行荧光标记引物PCR毛细管电泳检测及启动子ATG前方1.4kb序列进行测序,与60例正常人群及NCBI数据库CFTR基因序列在线比对。结果66名CBAVD患者CFTR基因IVS10-11(TAAA)n基因型以(TAAA)9/(TAAA)10为主,约占50.00%(33/66),(TAAA)9/(TAAA)9基因型仅占21.21%(14/66),正常人群基因型则以(TAAA)9/(TAAA)9为主,约占78.33%(47/60),两组之间有显著的统计学差异(P<0.01);另外3种等位基因型(TAAA)10、(TAAA)11和(TAAA)12均只出现在CBAVD患者中。非条件logistic回归分析显示(TAAA)9/(TAAA)10基因型患CBAVD的风险是(TAAA)9/(TAAA)9基因型的9.22倍,如果出现(TAAA)10、(TAAA)11或(TAAA)12则患病风险会更高,CBAVD患者中均未发现启动子c.-165G>A变异。结论中国CBAVD患者CFTR基因IVS10-11(TAAA)n的基因型以(TAAA)9/(TAAA)10为主,与正常人群基因型(TAAA)9/(TAAA)9不同,且无与启动子c.-165G>A变异协同作用。

Objective Congenital bilateral absence of the vas deferens(CBAVD,OMIM 277180)is associated with variation of Cystic Fibrosis Transmembrane Conductance Regulator gene(CFTR,OMIM602421).Some studies have suggested that CFTR intron(IVS)10-11(TAAA)nshort tandem repeats(STR)is an important cis-acting element which can combine with FOXI1 transcription factor.This variation will lead to CBAVD if it associated with c.-165 G>A variation.The purpose of this study to discuss of the variants of CFTR gene IVS10-11(TAAA)nSTR and c.-165 G>A in Chinese CBAVD.Methods IVS10-11(TAAA)nSTR was detected by PCR and capillary electrophoresis,and fragments 1.4 kb upstream of the ATG start codon of the CFTR gene were sequenced in 66 cases of CBAVD compared with that of 60 normal males.CFTR gene sequence was comparatively analyzed with gene sequence in NCBI database.Results Main genotype of CFTR IVS10-11(TAAA)nwas(TAAA)9/(TAAA)10 in CBAVD group,the proportion accounted for 50.00%(33/66)and the genotype of(TAAA)9/(TAAA)9 was relatively rare,accounting for 21.21%(14/66).In normal males,the main genotype of CFTR IVS10-11(TAAA)nwas(TAAA)9/(TAAA)9 accounting for 78.33%(47/60).The other allele types(TAAA)10,(TAAA)11 and(TAAA)12 were only seen in CBAVD group.The risk of CBVD in genotype(TAAA)9/(TAAA)10 was 9.22 times higher than that in(TAAA)9/(TAAA)10 according to logistic regression analysis.There were higher odds ratio if combined with allele(TAAA)10,(TAAA)11 and(TAAA)12.There was no synergistic effect of c.-165 G>A variant.Conclusion Main genotype of CFTR IVS10-11(TAAA)nin CBAVD is(TAAA)9/(TAAA)10,which is different from that in normal people.There is no synergistic effect of c.-165 G>A variant in the occurrence of CBVD.