Triploid pregnancy-Clinical implications

Diandric triploid partial mole versus digynic nonmolar triploidy: is morphological assessment sufficient for the diagnostic distinction?

AIMS

Diagnostic separation of diandric triploid gestation, i.e. partial mole from digynic triploid gestation, is clinically relevant, as the former may progress to postmolar gestational trophoblastic neoplasia. The aim of the study was to investigate if the combination of abnormal histology combined with ploidy analysis-based triploidy is sufficient to accurately diagnose partial mole.

METHODS AND RESULTS

A genotype-phenotype correlation study was undertaken to reappraise histological parameters among 20 diandric triploid gestations and 22 digynic triploid gestations of comparable patient age, gestational weeks, and clinical presentations. Two villous populations, irregular villous contours, pseudoinclusions, and syncytiotrophoblast knuckles, were common in both groups. Villous size ≥2.5 mm, cistern formation, trophoblastic hyperplasia, and syncytiotrophoblast lacunae were significantly more common in the partial hydatidiform mole. Cistern formation had the highest positive predictive value (PPV) (93%) and highest specificity (96%) for diandric triploid gestation, although the sensitivity was 70%. Cistern formation combined with villous size ≥2.5 mm or trophoblast hyperplasia or syncytiotrophoblast lacunae had 100% specificity and PPV, but a marginal sensitivity of 60%-65%. A moderate interobserver agreement (Kappa = 0.57, Gwet's AC1 = 0.59) was achieved among four observers who assigned diagnosis of diandric triploid gestation or digynic triploidy solely based on histology.

CONCLUSIONS

None of histological parameters are unique to either diandric triploid gestation or digynic triploid gestation. Cistern formation is the most powerful discriminator, with 93% PPV and 70% sensitivity for diandric triploid gestation. While cistern formation combined with either trophoblastic hyperplasia or villous size ≥2.5 mm or syncytiotrophoblast lacunae has 100% PPV and specificity for diandric triploid gestation, the sensitivity is only 60% to 65%. Therefore, in the presence of triploidy, histological assessment is unable to precisely classify 35% to 40% of diandric triploid gestations or partial moles.

Morphology combined with HER2 D-DISH ploidy analysis to diagnose partial hydatidiform mole: an evaluation audit using molecular genotyping

AIMS

A hydatidiform mole (HM) is classified as complete (CHM) or partial (PHM) based on its morphology and genomic composition. Ancillary techniques are often required to confirm a morphologically suspected PHM diagnosis. This study sought to evaluate the clinical accuracy of PHM diagnosis using morphological assessment supported by HER2 dual-colour dual-hapten in situ hybridisation (D-DISH) ploidy determination.

METHODS

Over a 2-year period, our unit examined 1265 products of conception (POCs) from which 103 atypical POCs were diagnosed as PHM or non-molar conceptuses with the assistance of HER2 D-DISH ploidy analysis. We retrospectively audited a sample of 40 of these atypical POCs using short tandem repeat genotyping. DNA extracted from formalin-fixed paraffin-embedded tissue was genotyped using 24 polymorphic loci. Parental alleles in placental villi were identified by comparison to those in maternal decidua. To identify triploid PHM cases, we sought three alleles of equal peak height or two alleles with one allele peak twice the height of the other at each locus.

RESULTS

Thirty-six of the 40 cases (19 PHM and 17 non-molar) were successfully genotyped and demonstrated complete concordance with the original diagnosis. All PHMs were diandric triploid of dispermic origin. In two non-molar diploid cases, we identified suspected trisomies (13 and 18), which potentially explains the pregnancy loss in these cases.

CONCLUSIONS

This study validates the use of HER2 D-DISH ploidy analysis to support the diagnosis of a morphologically suspected PHM in our practice.

Novel scoring system provides high separation of diploidy and triploidy to aid partial hydatidiform mole diagnosis: an adaption of HER2 D-DISH for ploidy analysis

AIMS

Diagnosis of hydatidiform mole or molar pregnancy based on morphology alone can be challenging, particularly in early gestation, necessitating the use of ancillary techniques for accurate diagnosis. We sought to adapt the VENTANA HER2 dual-colour dual-hapten in-situ hybridisation (D-DISH) assay by using the internal chromosome 17 enumeration probe to determine ploidy status.

METHODS

We selected 25 products of conception, consisting of molar and non-molar cases, to validate the HER2 D-DISH assay. These cases had prior morphological assessment by a perinatal pathologist and ploidy analysis using molecular cytogenetics. Three independent observers, blinded to the original histopathological and genetic diagnosis, scored 10 representative areas on each slide. Interobserver variability was assessed by comparing the total scores of each observer using analysis of variance (ANOVA) and the kappa statistic.

RESULTS

Our ploidy scoring system accurately determined the correct number of diploid and triploid conceptuses, demonstrating complete concordance with pre-existing ploidy status and the initial diagnosis. Interobserver agreement between three independent scorers was robust: ANOVA (p=0.36) and kappa statistic (0.812, p<0.001). We achieved clear separation of average nuclear signals for diploid and triploid conceptuses, which was statistically significant (p<0.05). Employing our innovative scoring system, known as the 'rule of 5', we established ploidy decision thresholds for all 25 cases.

CONCLUSIONS

Our modified HER2 D-DISH ploidy assay simplifies the process of ploidy determination and improves the accuracy of morphological diagnosis of molar pregnancy. The HER2 D-DISH assay was selected for ploidy analysis due to the widespread availability of in-situ hybridisation in pathology laboratories.

Low-pass whole genome sequencing is a reliable and cost-effective approach for copy number variant analysis in the clinical setting

INTRODUCTION

Next generation sequencing technology has greatly reduced the cost and time required for sequencing a genome. An approach that is rapidly being adopted as an alternative method for CNV analysis is the low-pass whole genome sequencing (LP-WGS). Here, we evaluated the performance of LP-WGS to detect copy number variants (CNVs) in clinical cytogenetics.

MATERIALS AND METHODS

DNA samples with known CNVs detected by chromosomal microarray analyses (CMA) were selected for comparison and used as positive controls; our panel included 44 DNA samples (12 prenatal and 32 postnatal), comprising a total of 55 chromosome imbalances. The selected cases were chosen to provide a wide range of clinically relevant CNVs, the vast majority being associated with intellectual disability or recognizable syndromes. The chromosome imbalances ranged in size from 75 kb to 90.3 Mb, including aneuploidies and two cases of mosaicism.

RESULTS

All CNVs were successfully detected by LP-WGS, showing a high level of consistency and robust performance of the sequencing method. Notably, the size of chromosome imbalances detected by CMA and LP-WGS were compatible between the two different platforms, which indicates that the resolution and sensitivity of the LP-WGS approach are at least similar to those provided by CMA.

DISCUSSION

Our data show the potential use of LP-WGS to detect CNVs in clinical diagnosis and confirm the method as an alternative for chromosome imbalances detection. The diagnostic effectiveness and feasibility of LP-WGS, in this technical validation study, were evidenced by a clinically representative dataset of CNVs that allowed a systematic assessment of the detection power and the accuracy of the sequencing approach. Further, since the software used in this study is commercially available, the method can easily be tested and implemented in a routine diagnostic setting.

Non-invasive cell-free DNA-based approach for the diagnosis of clinical miscarriage: A retrospective study

OBJECTIVE

To evaluate cell-free DNA (cfDNA) testing as a non-invasive approach to detecting aneuploidies in clinical miscarriages.

DESIGN

A retrospective cohort study of women with pregnancy loss.

SETTING

Hospitals and genetic analysis laboratories.

POPULATION OR SAMPLE

Pregnancy losses in the period 2021-2022.

METHODS

Results derived from non-invasive cfDNA testing (Veriseq NIPT Solution V2) of maternal blood and invasive analysis of products of conception (POC) (Ion ReproSeq) compared in 120 women who suffered a miscarriage.

MAIN OUTCOME MEASURES

Concordance rate results, cfDNA testing performance, non-informative rate (NIR) and fetal fraction (FF).

RESULTS

We found no significant differences in the NIR between invasive (iPOC) and non-invasive (niPOC) analysis of POC (10.0% [12/120] versus 16.7% [20/120]). Of 120 samples, 90 provided an informative result in iPOC and niPOC groups (75%). cfDNA analysis correctly identified 74/87 (85.1%) samples (excluding triploidies). Sensitivity and specificity were 79.4% and 100%, respectively; all discordant cases were female. A binomial logistic model suggested fetal sex as the only variable influencing the concordance rate (P = 0.035). A Y-chromosome-based FF estimate allowed the optimal reclassification of cfDNA of non-informative male fetuses and a more accurate evaluation of cfDNA testing performance. The difference between the two FF estimates (native algorithm and Y-chromosome-based) suggests that female non-concordant cases may represent non-informative cases.

CONCLUSIONS

Cell-free DNA-based testing provides a non-invasive approach to determining the genetic cause of clinical miscarriage.

Chromosome analysis of foetal tissue from 1903 spontaneous abortion patients in 5 regions of China: a retrospective multicentre study

BACKGROUND

Abnormal foetal tissue chromosome karyotypes are one of the important pathogenic factors for spontaneous abortion (SA). To investigate the age and abnormal foetal karyotypes of 1903 couples who experienced SA.

METHODS

A retrospective multicentre study collected age and foetal tissue karyotypes CNV-seq data of 1903 SA couples from 6 hospitals in 5 regions from January 2017 to March 2022. The distribution and correlation of abnormal foetal tissue karyotypes were evaluated by using regions and age.

RESULTS

In our study, 1140 couples (60.5% of the total) had abnormal foetal tissue chromosome karyotypes in all regions. We found that there were differences in the number of abnormal foetal tissue chromosome karyotypes, of which the incidence of trisomy was higher. At the same time, the populations situated in the eastern region had a more triploid (15.5%) distribution, trisomy (58.1%) in the southern region, mosaicism (14.8%) and microduplication (31.7%) in the southwestern region, microdeletion (16.7%) in the northern region. There are variances across areas, and it is more common in the north. The incidence risk of prenatal chromosomal abnormalities varied according to age group.

CONCLUSION

The findings of this study suggest that the karyotypes of patients with abnormal foetal tissue chromosome abortion in different regions were different. Meanwhile, patients ≥ 35 years old had a higher risk of abnormal foetal tissue chromosome abortion.

Enhancing Fetal Anomaly Detection in Ultrasonography Images: A Review of Machine Learning-Based Approaches

Fetal development is a critical phase in prenatal care, demanding the timely identification of anomalies in ultrasound images to safeguard the well-being of both the unborn child and the mother. Medical imaging has played a pivotal role in detecting fetal abnormalities and malformations. However, despite significant advances in ultrasound technology, the accurate identification of irregularities in prenatal images continues to pose considerable challenges, often necessitating substantial time and expertise from medical professionals. In this review, we go through recent developments in machine learning (ML) methods applied to fetal ultrasound images. Specifically, we focus on a range of ML algorithms employed in the context of fetal ultrasound, encompassing tasks such as image classification, object recognition, and segmentation. We highlight how these innovative approaches can enhance ultrasound-based fetal anomaly detection and provide insights for future research and clinical implementations. Furthermore, we emphasize the need for further research in this domain where future investigations can contribute to more effective ultrasound-based fetal anomaly detection.

Sequential application of copy number variation sequencing and quantitative fluorescence polymerase chain reaction in genetic analysis of miscarriage and stillbirth

BACKGROUND

Copy number variation sequencing (CNV-seq) could detect most chromosomal abnormalities except polyploidy, and quantitative fluorescence polymerase chain reaction (QF-PCR) is a supplementary method to CNV-seq in triploid detection. This study aimed to evaluate the feasibility of sequential application of CNV-seq and QF-PCR in genetic analysis of miscarriage and stillbirth.

METHODS

A total of 261 fetal specimens were analyzed by CNV-seq, and QF-PCR was only further performed for samples with normal female karyotype identified by CNV-seq. Cost and turnaround time (TAT) was analyzed for sequential detection strategy. Subgroup analysis and logistic regression were carried out to evaluate the relationship between clinical characteristics (maternal age, gestational age, and number of pregnancy losses) and the occurrence of chromosomal abnormalities.

RESULTS

Abnormal results were obtained in 120 of 261 (45.98%) cases. Aneuploidy was the most common abnormality (37.55%), followed by triploidy (4.98%) and pathogenic copy number variations (pCNVs) (3.45%). CNV-seq could detect the triploidy with male karyotype, and QF-PCR could further identify the remaining triploidy with female karyotype. In this study, we found more male triploidies than female triploidies. With the same ability in chromosomal abnormalities detection, the cost of sequential strategy decreased by 17.35% compared with combined strategy. In subgroup analysis, significant difference was found in the frequency of total chromosomal abnormalities between early abortion group and late abortion group. Results of logistic regression showed a trend that pregnant women with advanced age, first-time abortion, and abortion earlier than 12 weeks were more likely to detect chromosomal aberrations in their products of conception.

CONCLUSION

Sequential application of CNV-seq and QF-PCR is an economic and practical strategy to identify chromosomal abnormalities in fetal tissue.

[Discordant Down syndrome risk calculation with low maternal serum markers: About five cases of digynic triploidies]

OBJECTIVE

We compare the risk of Down syndrome among five patients carrying a foetus with digynic triploidy and suggest a course of action for these particular serological profiles.

METHODS

The concentrations of the different markers used are transformed into multiples of the median by using each of the three software types present on the French market which then determine the risk of Down syndrome.

RESULTS

For comparable biochemical and ultrasound profiles, the risk of Down syndrome turns out to be vastly different depending on the type of software employed. The relevance of an immediate diagnostic procedure, of a cell free DNA test or of a basic ultrasound follow-up then arises, leading to a potentially variable care pathway for the patient.

CONCLUSIONS

This study confirms that for this type of biochemical profile, the laboratory's advisory service is fundamental, that a control ultrasound is essential and that an invasive procedure must be used almost invariably due to the extremely substantial risk factors.

Relationship between serum cadherin 6 and 11 levels and severe and early-onset preeclampsia: A pilot study

Objective:

Preeclampsia is a highly morbid disease of placental origin, life-threatening condition for both a pregnant woman and her fetus. Cadherin 6 and 11 are adhesion molecules that play an important role in trophoblastic development and placentation. In our study, we investigated the change in serum cadherin 6 and 11 levels in pregnant women with preeclampsia.

Materials and Methods:

Pregnant women with preeclampsia were selected and compared with healthy women (as a control group) for a one-year study. The serum alanine aminotransferase, aspartate aminotransferase, and cadherin levels 6 and 11 of participants were analyzed and compared.

Results:

A total of 189 pregnant women were subdivided into 2 groups as preeclamptic (n=94) and women with healthy pregnancy (n=95). The cadherin 6 and cadherin 11 levels of the preeclamptic patients were significantly higher than those in the control group (p=0.001), and they were found to be significantly higher mainly in patients with early-onset and severe preeclampsia group (p=0.001). The cut-off cadherin 6 and 11 values for severe preeclampsia were found as 98.174 ng/mL and 1.92 ng/mL; with sensitivity of 88.3% and 84% respectively (p=0.001).

Conclusion:

The data analysis showed elevated serum cadherin 6 and 11 levels associated with the severity and early onset of pre-eclampsia. Serum cadherin 6 and 11 levels can be a candidate marker for the prediction of preeclampsia.

Atypical preeclampsia before 20 weeks of gestation with multicystic placenta, hyperreactio luteinalis, and elevated sFlt-1/PlGF ratio as manifestations of fetal triploidy: A case report

Preeclampsia is one of the most common as well as most severe complications of pregnancy, characterized by new-onset hypertension and proteinuria or other organ dysfunction. It predominantly occurs after 20 weeks of gestation. Very rarely, it can be triggered earlier in some specific situations. Here we report a case of fetal triploidy presenting as an extraordinarily early-onset preeclampsia. A healthy 36-year-old multiparous woman who had conceived naturally was hospitalized due to acute-onset severe hypertension accompanied by proteinuria at 18 weeks of gestation. Laboratory testing ruled out the presence of underlying maternal disease. Ultrasound findings, including multicystic large placenta and multiple fetal anomalies, strongly suggested fetal triploidy. Maternal ovaries showed hyperreactio luteinalis. The soluble fms-like tyrosine kinase-1/ placental growth factor (sFlt-1/PlGF) ratio was elevated, at 270. Medical abortion was carried out at 19 weeks of gestation; thereafter, her symptoms quickly resolved. Fetal triploidy was confirmed by genetic testing. We should be aware that fetal disorders including triploidy as well as pre-existing maternal diseases can provoke such very early-onset preeclampsia. Fetal ultrasound evaluation is critical and the sFlt-1/PlGF ratio is important for prompt diagnosis and management to prevent adverse maternal outcomes associated with atypical preeclampsia before 20 weeks of gestation.

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Fetal ultrasound and the sFlt-1/PlGF ratio are important to diagnose preeclampsia even before 20 weeks of gestation.