The Retrospective Study Of The SNP Array Technology In Amniotic Fluids Cell Combined With Other Abnormal Prenatal Screenings In High-risk Women During The Second Or Third Trimester Of Pregnancy

Objective To investigate the relationship among different indications for prenatal diagnosis of chromosomal diseases and fetal chromosomal diseases.In the late stage of gestation(>24 weeks),high-risk pregnant women were analyzed by single nucleotide polymorphism arrays(SNP array)after amniocentesis,and the specific abnormal detection rate was studied to compare the detection rate of different indications.Methods Retrospective analysis from March 2015 to November 2017,amniocentesis was performed on the maternal who had indications for prenatal diagnosis(and pregnancy>24w)in Xiangtan Central Hospital.Furthermore,20ml amniotic fluids were extracted for single nucleotide polymorphism microarray(SNP array).After obtaining chromosome reports,genetic counseling was carried out,and outcomes of fetal pregnancy were followed up.Results(1)A total of 310 cases were collected,among which there were 24 cases of chromosomal abnormalities,with an abnormal rate of7.74%(24/310).Meanwhile,duplication/deletion of>5Mb in 9 cases(2.9%),and duplication/deletion of<5Mb in 15 cases(4.84%).(2)There are 7 cases in pathogenic genome copy number variation(CNVs)which detection rate is2.26%(7/310),3 of them choose induced labor,4 of them choose delivery.8cases in variants of unknown significance(VOUS)which detection rate is2.58%(8/310),analyzed by bioinformatics.2 of them choose induced labor,6of them choose delivery.Up to now(children age 8~+to 2~+years),there are no obvious abnormality in child growth and intellectual development.The cases of duplication/deletion of<5Mb in genome copy number variation all referred to ultrasonic index anomaly.(3)The abnormal detection rates of serology prenatal screening abnormality?ultrasonic index anomaly?senile gravida and two or more pointers are 5.88%(1/17)?7.84%(12/153)?33.3%(1/3)?7.81%(10/128).(4)The abnormal detection rates of ultrasonic index anomaly?ultrasonic index anomaly+serology prenatal screening abnormality?ultrasonic index anomaly+senile gravida?ultrasonic index anomaly+bad pregnancy history are 7.84%(12/153)?7.69%(5/65)?3.85%(1/26)?21.43%(3/14)?8.33(1/12).The group of ultrasonic index anomaly+bad pregnancy history's abnormal detection rates was higher than ultrasonic index anomaly and ultrasonic index anomaly+senile gravida and and the difference was statistically significant(p<0.05).(5)Among the ultrasonography abnormalities,the abnormal detection rates of cardiovascular system?urinary system?digestive System?umbilical cord are 7.69%(1/13)?17.65%(3/17)?16.67%(1/6)?14.29%(1/7).Conclusions(1)Compared with traditional methods,the SNP Array can effective increase the detection rate of micro deletions or micro repetition less than 5Mb CNVs.(2)The SNP Array technology combined with traditional prenatal screening methods can effectively improve the detection rate of chromosomal abnormalities.