Isolation of single circulating trophoblasts from maternal circulation for noninvasive fetal copy number variant profiling.

OBJECTIVE: To develop a multi-step workflow for the isolation of circulating extravillous trophoblasts (cEVTs) by describing the key steps enabling a semi-automated process, including a proprietary algorithm for fetal cell origin genetic confirmation and copy number variant (CNV) detection. METHODS: Determination of the limit of detection (LoD) for submicroscopic CNV was performed by serial experiments with genomic DNA and single cells from Coriell cell line biobank with known imbalances of different sizes. A pregnancy population of 372 women was prospectively enrolled and blindly analyzed to evaluate the current workflow. RESULTS: An LoD of 800 Kb was demonstrated with Coriell cell lines. This level of resolution was confirmed in the clinical cohort with the identification of a pathogenic CNV of 800 Kb, also detected by chromosomal microarray. The mean number of recovered cEVTs was 3.5 cells per sample with a significant reverse linear trend between gestational age and cEVT recovery rate and number of recovered cEVTs. In twin pregnanices, evaluation of zygosity, fetal sex and copy number profiling was performed in each individual cell. CONCLUSION: Our semi-automated methodology for the isolation and single-cell analysis of cEVTS supports the feasibility of a cell-based noninvasive prenatal test for fetal genomic profiling.

Preferences for a non-invasive prenatal test as first-line screening for Down Syndrome: A discrete choice experiment.

OBJECTIVE: To investigate preferences of pregnant women for the characteristics of prenatal testing, and to quantify their willingness-to-pay (WTP) for non-invasive prenatal testing (NIPT) as first-line screening for Down Syndrome. METHOD: A cross-sectional discrete choice experiment survey including five testing attributes was administered to 192 pregnant women (≤14 weeks' gestation) who were aged ≥21 years in Singapore. We calculated marginal WTP for improvements in testing characteristics and NIPT. RESULTS: We identified two groups of women with distinct preferences for prenatal testing. Women aged ≥35 years, with at least a university education, and with intention to terminate pregnancy of an affected fetus were more likely to be in the group with higher WTP for improvements in test characteristics. While participants valued increased detection rate and lower screen positive rate associated with NIPT, they also valued no risk of test failure and ability to test for birth defects using standard testing. The participants, on average, were not willing to pay for NIPT over the standard testing as a first-line screening test. CONCLUSIONS: As a first-line screening, NIPT was not preferred over standard testing. The prenatal consultations should focus on each testing characteristic equally as our findings show diverse preferences for testing characteristics.

Prediction of labour onset in women who present with symptoms of preterm labour using cervical length.

BACKGROUND: Diagnosis of preterm labour is difficult because initial symptoms and signs are often mild and may occur in continuing pregnancies. This study aims to investigate the utility of measuring cervical length, using transvaginal ultrasound, in women presenting to the delivery suite with symptoms of preterm labour. METHODS: This was a prospective cohort study performed in KK Women's and Children's Hospital, Singapore from September 2017 to July 2018. Women with singleton pregnancies, presenting with symptoms of contraction pain, between 24+ 0 to 36+ 6 weeks gestation, were included. Transvaginal ultrasound cervical length measurements were done at presentation to the labour ward, after four hours and in the following morning. The primary outcome of the study was delivery within 1 week. All statistical analyses were conducted with Microsoft Excel and Statistical Package for the Social Sciences. RESULTS: A total of 95 subjects were included. A one-millimeter increase in the 1st cervical length increases scan-to-delivery time by 0.802 days (p-value 0.003, CI 0.280-1.323). Receiver Operator Characteristic (ROC) curve analysis for prediction of delivery within 1 week showed an Area Under Curve (AUC) of 0.667, optimal cut-off value of 27.5mm (sensitivity 77.8 %, specificity 61.6 %). A one-millimetre increase in the 3rd cervical length increases scan-to-delivery time by 0.770 days (p-value 0.023, CI 0.108-1.432). ROC curve analysis for prediction of delivery within 1 week showed an AUC of 0.915, optimal cut-off value of 25.5mm (sensitivity 100 %, specificity 73.6 %). However, the change in cervical length over a period of 1 day was not significant in predicting delivery within 1 week. CONCLUSIONS: Our results indicate that by using a cervical length cut off of 27.5mm at presentation, we would have predicted 77.8 % of deliveries within 1 week. If we were to repeat the cervical length scan the next day, with the same cut-off of 27.5mm, we would have predicted 100 % of deliveries within 1 week. In our study, measuring the transvaginal ultrasound cervical length is a reliable diagnostic test for delivery within 1 week. However, the results are limited by the small sample size. Further studies should be conducted with a larger sample size.

Dinoprostone vaginal insert (DVI) versus adjunctive sweeping of membranes and DVI for term induction of labor.

AIM: To compare the efficacy and safety of dinoprostone vaginal insert (DVI) alone versus DVI with adjunctive sweeping of membranes (ASM) for induction of labor (IOL). METHODS: Single-center, prospective, randomized controlled trial; women with singleton term pregnancies, cervical dilation ≥1 and <3 cm, intact membranes allocated to either DVI or DVI with ASM. The primary outcome was vaginal delivery within 24 h of insertion. Secondary outcomes included mean time from insertion to delivery, tachysystole, operative delivery for non-reassuring fetal status (NRFS), tocolytics, fetal outcomes, pain information, and subject satisfaction. RESULTS: One hundred and four received DVI (Group 1) alone and 104 DVI with ASM (Group 2). The rate of vaginal delivery within 24 h was 53% versus 56%, cesarean rate 8.7% versus 10.6% in Groups 1 and 2 respectively. Although the duration of labor was similar in both groups, about 6% of women required additional ripening with dinoprostone vaginal tablets in Group 2 compared to 11.5% in Group 1 (p-value = 0.2). The frequency of hyperstimulation syndrome, failed induction, analgesic requirements, and fetal outcomes were comparable. The majority (83%-86%) in either cohort were satisfied with their labor experience. Multivariate logistic regression demonstrated a slightly better chance for vaginal delivery within 24 h (odds ratio [OR] 1.22 [95% confidence interval, CI 0.65-2.29]; p-value 0.53] for DVI with ASM, although statistically insignificant. Younger maternal age and multiparity (OR 10.36 [95% CI 4.88-23.67]; p-value <0.0001) contributed to successful IOL. CONCLUSION: DVI with ASM is at least as efficacious as DVI for cervical ripening with no increase in morbidity. Although DVI with ASM group less often needed additional dinoprostone tablets to complete the process of IOL (p-value = 0.2), adjunctive sweeping has not been shown to have a significant impact on the duration of labor or mode of delivery.

CD24 Ala/Val polymorphism and multiple sclerosis.

CD24 is expressed on a broad range of cells in the immune and central nervous systems and appears to be required for development of experimental autoimmune encephalomyelitis in mice. Association of a CD24 Ala/Val coding polymorphism with susceptibility to and progression of multiple sclerosis was recently reported. We typed this coding polymorphism in a combined cohort of 1,180 cases and 1,168 unrelated and family-based controls from Belgium and the UK, but were unable to confirm either association. Since the CD24 gene is part of a segmental duplication, special care is required for the identification and genotyping of single nucleotide polymorphisms.

SELPLG and SELP single-nucleotide polymorphisms in multiple sclerosis.

P-Selectin (SELP) and P-selectin glycoprotein ligand-1 (SELPLG) constitute a receptor/ligand complex involved in the recruitment of activated lymphocytes, a critical event in the pathogenesis of multiple sclerosis (MS). In order to determine whether genetic variation in these pivotal molecules influences susceptibility to MS, we genotyped 214 Italian patients compared with 220 Italian controls for three single-nucleotide polymorphisms (SNPs): SELPLG Met62Ile, SELP C-2123G and SELP Thr715Pro. No significant differences in both SELP SNPs were found between patients and controls, whereas a decreased frequency of the Met62Ile SNP was found in patients versus controls in the Italian population (P = 0.025). To confirm these preliminary findings, the Met62Ile SNP was analysed in 938 UK trio families. This SNP did not show evidence for association with susceptibility to MS in the larger UK cohort. Therefore, none of the SNPs investigated is associated with MS, although this analysis does not conclusively exclude SELPLG and SELP as genetic risk factors for MS as much variation remains untested.

Refining the analysis of a whole genome linkage disequilibrium association map: the United Kingdom results.

Individual genotyping of the 10 most promising markers identified in our previously reported screen for linkage disequilibrium (LD) in multiple sclerosis identified a number of effects which confound the analysis and are of general importance in the interpretation of results obtained using microsatellite markers typed in pooled DNA. In order to identify and characterise these effects, we individually genotyped 529 promising markers in 16 trio families. We then devised adapting factors, which were designed to correct for these confounders. This more extensive analysis of the previously published UK data set and the repeat analyses incorporating these adaptations led to the identification of two novel markers that may be associated with multiple sclerosis in this population, providing a close correlation between the results of pooled analysis and individual typing.

A second major histocompatibility complex susceptibility locus for multiple sclerosis.

OBJECTIVE: Variation in the major histocompatibility complex (MHC) on chromosome 6p21 is known to influence susceptibility to multiple sclerosis with the strongest effect originating from the HLA-DRB1 gene in the class II region. The possibility that other genes in the MHC independently influence susceptibility to multiple sclerosis has been suggested but remains unconfirmed. METHODS: Using a combination of microsatellite, single nucleotide polymorphism, and human leukocyte antigen (HLA) typing, we screened the MHC in trio families looking for evidence of residual association above and beyond that attributable to the established DRB1*1501 risk haplotype. We then refined this analysis by extending the genotyping of classical HLA loci into independent cases and control subjects. RESULTS: Screening confirmed the presence of residual association and suggested that this was maximal in the region of the HLA-C gene. Extending analysis of the classical loci confirmed that this residual association is partly due to allelic heterogeneity at the HLA-DRB1 locus, but also reflects an independent effect from the HLA-C gene. Specifically, the HLA-C*05 allele, or a variant in tight linkage disequilibrium with it, appears to exert a protective effect (p = 3.3 x 10(-5)). INTERPRETATION: Variation in the HLA-C gene influences susceptibility to multiple sclerosis independently of any effect attributable to the nearby HLA-DRB1 gene.

A high-density screen for linkage in multiple sclerosis.

To provide a definitive linkage map for multiple sclerosis, we have genotyped the Illumina BeadArray linkage mapping panel (version 4) in a data set of 730 multiplex families of Northern European descent. After the application of stringent quality thresholds, data from 4,506 markers in 2,692 individuals were included in the analysis. Multipoint nonparametric linkage analysis revealed highly significant linkage in the major histocompatibility complex (MHC) on chromosome 6p21 (maximum LOD score [MLS] 11.66) and suggestive linkage on chromosomes 17q23 (MLS 2.45) and 5q33 (MLS 2.18). This set of markers achieved a mean information extraction of 79.3% across the genome, with a Mendelian inconsistency rate of only 0.002%. Stratification based on carriage of the multiple sclerosis-associated DRB1*1501 allele failed to identify any other region of linkage with genomewide significance. However, ordered-subset analysis suggested that there may be an additional locus on chromosome 19p13 that acts independent of the main MHC locus. These data illustrate the substantial increase in power that can be achieved with use of the latest tools emerging from the Human Genome Project and indicate that future attempts to systematically identify susceptibility genes for multiple sclerosis will have to involve large sample sizes and an association-based methodology.