Objective: Traditional prenatal diagnosis for congenital diseases were villus sampling and amniocentesis. These invasive diagnosis methods are not only technical complicated, but also harmful to mother or fetus. Fetus in its different gestational age has its different type of hemoglobin or different amount of hemoglobin, especially epsilon hemoglobin exiting in the body of 10 weeks gestation fetal, however gamma hemoglobin has its high amount before baby to be born. But epsilon and gamma hemoglobin did not exist in the bodies of adults bodies. It is possible to use advanced molecular biological technique to extract the fetal hemoglobin gene from maternal peripheral blood. In articles from domestic and abroad, no report related to fetal hemoglobin extraction from maternal peripheral blood was found. We tried to use non-invasive method to detect fetal hemoglobin epsilon/gamma gene from maternal peripheral blood by molecular biological technique. The purpose was to establish a convenient, sensitive and special method to be a basis of screening prenatal diseases in the population and lay a basis for family planning and clinical application.
Methods: Blood samples were collected and the fetal mRNA extracted from the pregnant women with the use of random primer. We used ultraviolet spectrophotometer to test the concentration and purity of extracted mRNA are suitable for reverse transcription. Reverse transcription of mRNA into cDNA was carried out and cDNA by PCR with the special epsilon/gamma primer being used. Via 1.2% EB in agarose gel electrophoresis, we used "Gel Works System" to scan the electrophoresis image to detect epsilon/gamma gene band.
Results: The peripheral blood of pregnant women was collected. With RT-PCR and agarose gel electrophoresis method, we detected epsilon/gamma gene successfully in 7 samples with 6 positive and 1 negative.
Conclusion: This was the first time that we used non-invasive way to detect expression of fetal epsilon/gamma gene in maternal blood to have found that this was a simple method to separate fetal cells from maternal blood, and could easily be accepted by pregnant women. Success of RT-PCR to detect fetal specific mRNA gave the hint that this method could be used in the field of prenatal diagnosis of hemoglobin disease, predicting fetal gender, predicting Rh blood type and single gene disease and be used widespread in prenatal diagnosis.