AIRE基因在21-三体综合征无创性产前诊断中应用的可行性研究

目的利用AIRE基因母、胎间差异甲基化，探讨其在无创性产前诊断21-三体综合征患儿中的应用价值。方法随机选择健康的孕妇、非妊娠妇女、21-三体妊娠的孕妇血浆、血细胞、绒毛和胎盘组织，利用甲基化敏感限制性内切酶法，酶切后进行常规PCR检测目的基因AIRE的甲基化模式，分析其影响因素。结果AIRE基因在非妊娠妇女的血细胞和血浆中及妊娠妇女的血细胞中均未甲基化，而在孕妇血浆中高甲基化，且与孕妇绒毛组织和胎盘组织AIRE基因甲基化状态相同，两组间甲基化率差异显著有统计学意义（P〈0．0001）。且母胎间差异甲基化不受孕妇年龄、孕周和胎儿性别的影响。孕早、中、晚期孕妇血浆中甲基化检出率分别为87％、97％、97％稍有不同，但无统计学意义。21-三体妊娠妇女血浆中游离胎儿DNA浓度约为正常孕妇血浆中游离胎儿DNA的2倍。结论在母体和胎儿DNA中AIRE基因甲基化有显著差异，可作为孕妇血浆中胎儿游离DNA表观遗传学标记，有望进行21-三体综合征的无创性产前诊断。

Study on non - invasive prenatal diagnosis of Down syndrome by AIRE gene

Objective： To investigate differential methylation of AIRE gene between mother and child and it＇s using in the non - invasive prenatal diagnosis Down syndrome. Methods ： By using methylation sensitive restriction enzyme to cut DNA of plasma, blood cells, the villi and placenta tissue of healthy pregnant and non pregnant women and pregnant women of trisomy 21. After that, PCR detection AIRE gene methylation pattern, to analyze its influencing factors. Results： AIRE gene are not methylation in the blood cells and plasma of not pregnant women and in the blood ceils of pregnant women, while in plasma of pregnant women is high methylation, just the same as pregnant women of villi and placenta tissue AIRE gene methylation status, methylation rate was significant difference between the two groups. Concentrations of free fetal DNA of trisomy 21 pregnant women is two times of normal pregnant women free fe-tal DNA in plasma. Conclusions AIRE gene in maternal and fetal DNA methylation have significant differences, can be used as a free fetal DNA in plasma of pregnant women epigenetic markers, is expected to trisomy 21 syndrome of noninvasive prenatal diagnosis.