Application value of modified magnetic bead screening for enrichment of cell-free fetal DNA from maternal peripheral blood in non-invasive prenatal testing / 中华围产医学杂志

Objective:To evaluate the value of modified magnetic bead screening for enrichment of cell-free fetal DNA (cffDNA) in non-invasive prenatal testing (NIPT).Methods:This study retrospectively recruited 31 cases with low concentration of cffDNA (<6.00%), Z value in the gray zone (3.00-4.00) at the first detection, or false-positive (confirmed by invasive prenatal diagnosis) or false-negative (confirmed by postnatal chromosome test) results among 11 000 pregnant women who underwent routine NIPT in Beijing Haidian District Maternal and Child Health Care Hospital from October 2017 to December 2019. Plasma samples collected for the first-time routine NIPT were used to enrich cffDNA using modified magnetic beads for NIPT (modified NIPT). Wilcoxon rank sum test was used to compare the modified NIPT with the routine NIPT in detecting the cffDNA concentrations of male fetuses.Results:Among the 31 pregnant women, there were 13 cases with low cffDNA concentration in routine NIPT, 11 having false-positive results in the routine NIPT (three for trisomy 13, four for trisomy 18 and four for trisomy 21, all were confirmed by invasive prenatal diagnosis), six with gray-zone Z values in the first-time NIPT (retesting indicating low risk) and one having false negative result for trisomy 21 (confirmed by postnatal chromosome test). Cell-free DNA (cfDNA) fragments less than 150 bp were effectively enriched using the modified magnetic bead screening and the concentration of cffDNA was increased from 4.43% (2.45%-17.61%) in routine NIPT to 13.46% (7.75%-36.64%) in the modified NIPT ( Z=-14.22, P<0.01). Results of the modified NIPT indicated that 13 cases with low cffDNA concentration of routine NIPT were successfully detected as low risk, as well as the risks in the six cases with gray-zone Z value and six of the 11 false-positive cases in the routine NIPT were low, which were consistent with the retest results of the routine NIPT, while high risk was found in one false-negative case. Conclusions:The modified NIPT could reduce the false positive rate by lowering the failure rate caused by low concentration of cffDNA and is able to identify false-negative cases. Compared with the routine NIPT, it shows a higher success rate and a lower false positive rate.

Effect of NAIF1 on IFIT Family Proteins in Gastric Cancer / 肿瘤防治研究

Objective To investigate the effect of NAIF1 in gastric cancer cell lines MKN45. Methods We constructed pLVX-Tight-Flag-NAIF1-puro plasmid with Tet-on system. DOX was added to induce NAIF1 expression in MKN45 cells. The cells were collected at 0, 6, 12 and 24 hours after DOX addition for gene expression microarray detection and biological analysis of differentially expressed genes. qRT-PCR and Western blot were used to verify the changes in mRNA and protein levels of the selected target differential genes. Results The biological analysis of gene microarray hybridization results showed that IFIT1, IFIT2 and IFIT3 expression significantly increased at 24h, qRT-PCR also showed this change, and Western blot further verified the change in protein level. However, IFIT5 showed no significant change in mRNA and gene expression. Conclusion Over-expression of NAIF1 in gastric cancer cells can promote the expression of some immune system-related IFIT family proteins.

Problems with clinical application of non-invasive prenatal testing / 中华医学遗传学杂志

With the development of high-throughput sequencing technology, non-invasive prenatal testing (NIPT) has been rapidly used for fetal chromosomal aneuploidy screening and gradually become a first-line test. With the increase of sequencing depth and improvement of bioinformatic analysis ability, NIPT technology may also be used to detect chromosomal copy number variations and certain single gene diseases in fetuses. However, it has also encountered some problems such as insufficient understanding by different groups, false-positive and false-negative results, and selection of appropriate subjects and gestational age. This article has given a summary for such problems.

Screening for hotspot mutations associated with genetic hearing impairment in pregnant women and subsequent prenatal diagnosis in high risk pregnancies / 中华耳鼻咽喉头颈外科杂志

Objective@#To screen for hotspot gene mutations associated with genetic deafness in Chinese pregnant women, and to perform risk assessment and prenatal diagnosis in high-risk families.@*Methods@#Between November 2012 and October 2017, 26 117 pregnant women were screened by molecular hybridization microarray for 9 hot-spot mutations in 4 hereditary deafness related genes (GJB2 c. 35 del G, c. 176_191 del 16 bp, c. 235 del G, c. 299_300 del AT, GJB3 c. 538 C>T, SLC26A4 c. 2168 A>G, IVS 7-2 A>G, mitochondrial DNA 12S rRNA m. 1494 C>T, m. 1555 A>G). Genotype analysis was carried out in husbands of women carrying mutations, and prenatal diagnosis was carried out in the fetuses with high risk of deafness.@*Results@#Among all women tested, 1 208(4.63%) were carriers of genetic deafness mutations, 7 with hearing impairment were affected by homozygous or compound heterozygous mutations, 51 were mitochondrial gene mutation carriers, 103 were carriers of GJB3 c. 538 C>T heterozygous mutation, 1 026 were carriers of GJB2 or SLC26A4 heterozygous mutations, and 21 carried heterozygous mutations in two genes simultaneously. In 394 families, the husbands accepted gene sequence testing, and 27 in which were determined as carriers of mutations in identical genes as their wives. Among which, 18 families received prenatal diagnosis, and 5 fetuses were diagnosed as hereditary deafness. In 9 families who did not receive prenatal diagnosis, 1 neonate was diagnosed as compound heterozygote after delivery.@*Conclusion@#In order to prevent birth defects with congenital hearing problems, it is effective to provide screening for hotspot mutations in pregnant women and to perform prenatal diagnosis on high risk pregnancies.

Application of copy number variation analysis based on next-generation sequencing in the genetic analysis of missed abortion chorionic villi / 中华妇产科杂志

Objective To investigate the value of copy number variation analysis based on next-generation sequencing (NGS-CNVA) in the genetic analysis of missed abortion chorionic villi. Methods From August 2012 to May 2014, chorionic villi from 74 cases of missed abortion at 6-13 gestational weeks in Haidian Maternal and Child Health Hospital were collected and analyzed by karyotype analysis and NGS-CNVA. The results of the two methods were compared. Results (1) Karyotype analysis was carried out for the villi from the 74 missed abortion patients. Thirty cases were euploid, 26 cases were aneuploid, while 18 cases had structural abnormalities. The resolution of the karyotyping was 320 bands and the average report time was 22 days. (2) All of the 74 samples obtained NGS-CNVA results and the report time was 7-10 days. (3) The NGS-CNVA results of 56 cases were consistent with karyotype. Among them, 28 cases (28/56, 50%) had no copy number variants (CNV), and 19 cases (19/56, 34%)had CNV between 1 Mb and 10 Mb. 9 cases (9/56,16%) had CNV≥10 Mb found by NGS-CNVA, but not found by karyotyping. (4) According to the results of NGS-CNVA, karyotype were reviewed. The reviewed results found 7 cases with CNV<10 Mb and 3 cases with CNV≥10 Mb in 30 cases which got normal karyotype results at the first analysis. (5) Among the 18 cases of structural abnormalities, 6 cases were Robertsonian translocation. Sequencing technology could confirm the specific area of chromosome deletion/duplication in 8 cases, but could not locate them. Conclusions NGS-CNVA has lower failure rate, higher resolution, lower specimen requirement and shorter report time than karyotype analysis when used for the genetic analysis of missed chorionic villi . NGS-CNVA could be a useful genetic analysis method for the missed abortion villi.

Detection of small supernumerary marker chromosome by single nucleotide polymorphism microarray chips / 中华儿科杂志

<p><b>OBJECTIVE</b>To apply single nucleotide polymorphism (SNP) microarray for delineation of small supernumerary marker chromosome (sSMC) in two newborns.</p><p><b>METHOD</b>Chromosome karyotyping was performed on newborns who were born in Jan. 2013 and Jan. 2014 in Haidian Maternal and Child Health Hospital because of the abnormalities found in pregnancy checkups. SNP microarray analysis was carried out on 2 newborns with de novo sSMCs (one was mos 47,XY, + mar[45]/46,XY[5] and the other was mos 47, XY, + mar [30]/46, XY [20]), which could not be determined by conventional banding techniques. Genomic DNA was extracted from cord blood samples, amplified, tagged and hybridized following the manufacturer' s protocol. Data were collected and analyzed.</p><p><b>RESULT</b>There was a 78. 6 Mb duplication in chromosome 8 for Newborn A, which was associated with 8p22 duplication syndrome; and a 32. 7 Mb duplication in chromosome 13 for Newborn B, which was not yet reported definitely as pathogenic. The newborn A was identified with agenesis of the corpus callosum, obvious right eyelid drooping, the onset of low muscle tone and mental developmental lag behind their peers, while the newborn B had normal findings on physical and mental evaluation.</p><p><b>CONCLUSION</b>SNP-array can identify sSMCs of newborns at the DNA level, and can be used as an important supplement to the conventional karyotype analysis, but the pathogenicity of positive outputs need further verification.</p>

Analysis of the Rate of Common Genetic Mutations of Deaf in Pregnant Women / 中国医科大学学报

Objective To carry out a molecular screening of Chinese common deafness gene mutations in Chinese pregnant women group,so as to expatiate on the content,provide molecular epidemiological data,reduce the birth rate and provide a theoretical basis to the deaf children. Methods The molecular detection was done to the pregnant women underwent normal antenatal care in our hospital,using gene chips to screen the four com?mon deaf genes(GJB2,GJB3,SLC26A4 and mitochondrial 12S rRNA)in China;then,the newborn infants carrying mutations were treated with the hearing screening,using the methods of Otoacoustic Emissions(OAE)and Brainstem Auditory Evoked Potentials(BAEP),and the husbands of mutation carrying pregnant women were adopted molecular testing of the deaf susceptibility genes in order to investigate the correlation of the rate of pregnant women carrying the mutant genes and newborn infants deafness. Results Totally 2 067 cases of pregnant women were accepted to do the molecular screening,there were 110 cases of deafness mutations detected(5.320%),in which GJB2 gene(67 cases),GJB3 gene(6 cases), SLC26A4gene(33 cases),mitochondrial 12SrRNAgene(4 cases)mutation detection rates were 3.240%,0.290%,1.600%and 0.190%,respec?tively;especially:GJB2gene 235 del C,GJB2gene 299 del AT double mutant 1 case;GJB2gene 299 del AT,GJB3gene 538 C>T double mutant 1 case;GJB2 gene 235 del C,SLC26A4 gene IVS7?2 A>G double mutant 1 case. About 108 cases children newborn accepted to do the hearing screening,in which 3 cases had problems with the left ear,3 cases with the right ear,and 4 cases with the double ears. Conclusion The use of ge?netic deafness gene chip to do the molecular diagnostics in pregnant women can be convenient,fast and efficient for prenatal diagnosis of deafness, which provides a theoretical basis and good method for reducing the birth rate of deaf children and should be popularized more widely.