利用母体血浆游离胎儿DNA进行胎儿SRY基因定量检测

Quantitative analysis of fetal sex-determining region of Y-chromosome gene by cell-free fetal nucleic acids in maternal plasma

目的探讨胎儿游离DNA在无创性产前诊断中的应用价值。方法行产前诊断的孕妇87例,分为中期妊娠(16～24周)61例(中孕组)和早期妊娠(11～14周)26例(早孕组),采用实时荧光定量PCR方法,利用Taqman探针对妊娠早、中期孕妇血浆游离的胎儿Y染色体性别决定基因(sex-determining region of Y-chromosome,SRY)进行扩增和定量分析。结果孕13周后的样本均得到特异性扩增,特异度和灵敏度均为100%;中孕组男性胎儿SRY检测的平均DNA浓度为155.46copies/mL血浆,实测范围为43.6～326.8copies/mL血浆;早孕组平均浓度为26.42copies/mL血浆,实测范围为14.3～73.3copies/mL血浆。结论采用荧光实时定量PCR在妊娠早、中期可稳定检测到胎儿游离DNA,可作为孕期性连锁遗传性疾病研究或产前诊断的有效补充手段。

Objective To explore the clinical application value of cell-free fetal nucleic acids to non-invasive prenatal diagnosis.Methods Real-time quantitative PCR and Taqman probes were used for amplification and quantitative analysis of sex-determining region of Y-chromosome（SRY） gene in maternal serum in 87 pregnancy women,including 61 mid-trimester（16～24 weeks） and 26 first trimester（11～14 weeks） pregnancy women.Results All the samples were amplified specifically and sensitively after pregnancy for over 13 weeks,with the specificity and sensitivity of 100% respectively.In the mid-trimester pregnancy group the average concentration of male fetal SRY gene was 155.46 copies/mL plasma and the measured concentration range was from 43.6 to 326.8 copies/mL plasma.In the first-trimester pregnancy group the average concentration of SRY gene was 26.42 copies/mL plasma,and the measured concentration range was from 14.3 to 73.3 copies/mL plasma.Conclusion Real-time PCR is a steady method to diagnose fetal sex in the first-trimester and mid-trimester pregnancy women by fetal cell free DNA.The program can be used as an effectively supplementary method in the prenatal diagnosis of sex-linked genetic disease.