[Application of single nucleotide polymorphism array in prenatal diagnosis for fetuses with abnormal ultrasound findings].

Objective: To investigate the value of single nucleotide polymorphism array (SNP-array) for fetuses with abnormal ultrasound findings. Method: A total of 904 fetuses with abnormal ultrasound findings were enrolled in this study from May 2015 to November 2017, and 434 (48.0%) cases received conventional karyotyping analysis at the same time. According to different abnormal ultrasound category, 904 cases were divided into 5 groups: 280 cases (31.0%) in single system structural anomalies, 31 cases (3.4%) in multiple system structural anomalies, 331 cases (36.6%) in single ultrasound soft marker abnormalities without structural anomalies, 107 cases (11.8%) in multiple soft marker abnormalities and 155 cases (17.2%) in structural abnormalities combined with soft markers abnormalities. Abnormal detection rates by SNP-array among 5 groups of abnormal ultrasound category were calculated. Result: (1) Total SNP-array results: 171 (19.0%) cases out of 904 cases analyzed by SNP-array, presented chromosomal abnormalities. Pathogenic copy number variants were detected in 27 cases (3.0%) and variants of unknown significance were detected in 81 cases (7.8%) . In addition, 7 cases (26.0%) were found with new mutation by parental validation. (2) SNP-array of 5 groups: among the 5 groups of abnormal ultrasound category, chromosomal abnormalities were identified by SNP-array in 19.3% (54/280) with single system structural abnormalities, 25.8% (8/31) with multiple system structural abnormalities, 13.9% (46/331) with single nonstructural anomalies, 19.6% (21/107) with multiple nonstructural anomalies and 27.1% (42/155) with structural abnormalities combined with nonstructural anomalies. The differences were significant (P=0.010) . No chromosome abnormalities was identified in single soft marker abnormalities, such as choroid plexus cysts, echogenic foci in the heart, single umbilical artery and pyelectasis. (3) Chromosomal abnormalities: the abnormal detection rate of aneuploidy chromosomal abnormalities by SNP-array increased with the maternal age, decreased with the gestational weeks (all P<0.05) . However, the pathogenic copy number variants and variants of unknown significance rates did not change with maternal age and gestational weeks (all P>0.05) . (4) SNP-array and karyotyping: 434 cases were analyzed by conventional karyotyping and SNP-array respectively, 10.3% (43/419) of which presented chromosomal abnormalities by conventional karyotyping and 18.7% (81/434) of which presented chromosomal abnormalities by SNP-array. Conclusions: SNP-array could be a useful genetic analysis method in prenatal diagnosis for fetuses with abnormal ultrasound findings. For different abnormal ultrasound category, SNP-array has different detection rate. Compared with conventional karyotyping analysis, SNP-array can improve the detection rates for chromosomal abnormalities and find the chromosome abnormalities which can't be detected by conventional karyotyping analysis. In clinical prenatal genetic counseling, SNP-array should be selected rationally in combination with the various abnormal ultrasound category.

Decomposition Kinetics of Omethoate in Blood.

OBJECTIVES: To study the decomposition kinetics of omethoate in blood. METHODS: The acetonitrile precipitated protein was added into the blood, with the chromatographic column of a Waters BEH C18 column （2.1 mm×50 mm, 1.7 µm）, the mobile phase of 5 mmol/L ammonium acetate aqueous solution-methanol, and the gradient elution with a flow rate of 0.3 mL/min and injection volume of 2 µL. With electrospray ionization （ESI） source and positive ion detection, qualitative and quantitative analyses were taken using multi-reaction monitoring mode. Omethoate standard was added into blank human blood to the mass concentrations of 0.78, 1.40, 2.30, 4.50, and 7.20 µg/mL, and each mass concentration was preserved at 3 temperatures of -20 ℃, 4 ℃, and 20 ℃, respectively. The content of omethoate was detected at different time points （0, 1, 3, 4, 7, 11, 15, 24, 32, 40, 48, 64, 80, 96, and 120 d）. RESULTS: Different concentrations of omethoate all showed a descended trend in human blood under different temperature conditions. The decomposition in storage environment of -20 ℃, 4 ℃, and 20 ℃ was fit to a one-compartment open model with a first-order kinetic process, which could be expressed as Ct=Coe-αt, with the calculated theoretical values of omethoate concentration close to the measured values. CONCLUSIONS: All concentrations of omethoate are decomposed in the blood, which vary a lot in different preservation conditions. It is suggested that blood samples should be frozen and detected timely in suspected omethoate poisoning cases.