Study On The Application Of Noninvasive Prenatal Test Based On Free Fetal DNA In The Detection Of Fetal Beta Thalassemia

Objective In order to avoid the traditional invasive prenatal diagnostic methods which may cause complications by exploring establish the technology for noninvasive prenatal diagnosis of fetal thalassemia.Next,using related technologies and methods of noninvasive prenatal testing based on cell free fetal DNA,further to explore and improve techniques of noninvasive prenatal testing about β-thalassemia.Study its application value in prenatal diagnosis of β-thalassemia.To assess the accuracy and stability assessment of noninvasive prenatal testing technology by comparing the testing result with gold standard of the traditional prenatal diagnosis method.To achieve the goal of striving noninvasive prenatal testing technology for early clinical application and diagnosis.Methods Thalassemia patients have been chose from those women who underwent routine obstetric outpatient prenatal examination from January 2015 to March 2017 in the First Affiliated Hospital of Hainan Medical University,and it was ensure that the couples are the carrier of β-thalassemia mutation,then the informed consent has been signed by pregnant women and their husbands.Firstly,peripheral blood of the couples’ forearm were extracted using EDTA K2 anticoagulation blood sampling.Through the detection of free fetal DNA in maternal peripheral blood,fetal thalassemia genetype has been got,which applying the following two techniques:AMP combined with two generation sequencing technology and taget sequencing technology detecting SNP,by using a series of technical operation,and then compared this result with the gold standard.Secondly,it has been got fetal thalassemia genetype using the traditional invasive prenatal diagnosis of amniocentesis for two pregnant women by PCR combined with RBD technology,and taked the detection results as the gold standard for prenatal diagnosis of β-thalassemia.Finally,it comes to the conclusion that the accuracy and stability of noninvasive prenatal test.Results Experiment one:The noninvasive prenatal testing method of AMP combined with two generation sequencing technology,it has been got fetal thalassemia genotypes through comparing and calculating after sequencing.The result of thalassemia gene type of paternal genetic was consistent with the fetal gene type of amniotic fluid cells.Experiment two:1.By using next generation sequencing to detect SNP of free fetal DNA in noninvasive prenatal testing,it has successfully tested the genotype of fetus,for couples who carry the same genotype of thalassemia;2.It has been got fetal thalassemia genotypes through comparing and calculating after sequencing.These results were consistent with the gold standard of traditional invasive diagnosis,the accuracy rate of AMP combined with two generation sequencing technology was 100%.Conclusions1.Taking the technology of AMP combined with two generation sequencing as a non-invasive prenatal testing technology,which is suitable for couples with different mutation of β-thalassemia cases.2.Taking the technology of two generation sequencing detecting SNP in fetal DNA,it has also detected fetal thalassemia genetype,which is suitable for couples with different mutation of β-thalassemia cases.