Study On Prenatal Dianosis Using Cell-free Fetal DNA In Maternal Plasma

In 1997, by using Y chromosome-specific sequences as a fetal marker,Lo and coworkers demonstrated the presence of fetal DNA in the plasma and serum of pregnant women carrying male fetuses.The analysis of fetal DNA in maternal plasma can be used for sex-linked recessive inheritance, fetal RhD genotyping and Down's syndrome .Impressed by these highly promosing results ,the British National Blood service has recently adopted the use of maternal plasma for fetal RhD genotyping as a routine prenatal diagnostic test. Free circulating fetal DNA found in blood plasma and serum have been of special interest to investigators over recent years in the development of noninvasive methods for disease diagnosis and monitoring. Its discovery has paved a new way for noninvasive prenatal diagnosis.Hemolytic disease of the newborn (HDN) and neonatal alloimmue thrombocytopenic purpura (NAITP) are potentially fatal conditions caused by maternal alloantibodies directed against paternally inherited antigens on fetal red cells,platelets.HDN and NAITP are most commonly associated with blood group antigens ,such as RhE,human platelet alloantigens (HPA) ,may provoke an immune response in the mother .In the first part, we develop a nested polymerase chain reaction(PCR) technique for fetal SRY gene identification using cell free fetal DNA that was extracted by the phenol/chloroform method from maternal plasma.The accurary was 93.3 percent and the nested PCR amplification of SRY sequence is a convenient and low cost approach for the noninvasive early prenatal diagnosis of sex-linked inheritant diseases.