Double and multiple chromosomal aneuploidies in spontaneous abortions: A single institutional experience

Association of Biochemical Parameters and Screening for Mutations in the MCU Gene in Alzheimer's Disease Patients

The most prevalent form of dementia, Alzheimer's disease (AD) is a chronic illness that is on the rise among the geriatric population. Even though research into its biochemical, genetic, and cytogenetic pathways has advanced, its aetiology is still unclear and complex. In this study, we recruited sixty-eight participants diagnosed with AD where the cytogenetic, biochemical parameters and genetic mutations were analysed. Our results revealed chromosomal aberrations such as aneuploidies in the peripheral blood of Alzheimer's disease patients. Biochemical parameters revealed no statistical significance in the study though a pattern could be observed in the serum levels. Further few novel mutations at the c.21 C > T, c.56G > A were observed in the MCU gene of mitochondrial calcium uniporter. All these findings reveal the need for a larger cohort study to gain a better and more detailed understanding of the aetiology of Alzheimer's disease.

Application of Chromosomal Microarray Analysis in Genetic Reasons of Miscarriage Tissues

Background

The potential causes of miscarriage are very complex, including genetic, immune, infectious, and endocrine factors. 50%-60% of miscarriages are caused by chromosomal abnormalities. Chromosomal microarray analysis (CMA) is a key tool in this context, capable of detecting not only copy number variations (CNV) but also loss of heterozygosity (LOH). CMA has been used as a tool to investigate the genetic reasons for miscarriage.

Methods

In our study, chromosomal microarray analysis (CMA) conducted 1220 miscarriage villous tissues. The results from this technology were used to identify the genetic reasons for miscarriage and evaluated strategies for subsequent pre-pregnancy planning.

Results

Here, the abnormality rate of miscarriage was 56.07%(684/1220). The aneuploidy rate accounted for 81.14%(555/684), and was significantly higher in group >35-year-old age. The second most common genetic reason for miscarriage was polyploidy, accounting for 10.09%(69/684). Additionally, we discovered loss of heterozygosity (LOH) in a small percentage of cases, accounting for 2.20%(15/684) reason for miscarriage genetic reasons, due to the advantage of CMA can detect isodisomy (a kind of uniparental disomy). 45 cases (6.58%) with copy number variants, which due to the CMA can detect copy number variations.

Conclusion

Our study indicated that miscarriage villous tissues should be performed genetic analysis, seek help from professional genetic counseling.

Double Trisomy 16 and 22 Clinically Mimic Partial Hydatidiform Mole in a Case of Subsequent Pregnancy Loss

A case of double trisomy 16 and 22 in the second pregnancy loss is presented. DNA analyses (short tandem repeats genotyping) of miscarriage specimen was indicated because of ultrasound suspicion of partial hydatidiform mole. After the partial hydatidiform mole exclusion, further DNA analyses focused on the most common aneuploidies causing pregnancy loss, detected double trisomy 16 and 22 in the product of conception. The couple was referred to clinical genetic consultation and normal parental karyotypes were proved. For further explanatory purposes, archived material from the first pregnancy loss was analyzed and trisomy of chromosome 18 was detected. By comparison of allelic profiles of the mother, father, and both losses, the maternal origin of all aneuploidies was proven what can be attributed to frequent meiosis errors, probably due to advanced maternal age (44 years at the first loss and 45 years at the second loss). In conclusion, aneuploidies can mimic partial hydatidiform mole. Genetic analysis is helpful on the one hand to rule out partial hydatidiform mole and on the other hand to identify aneuploidies and in this way to determine the cause of miscarriage.

Double Aneuploidy of Down Syndrome (Trisomy 21) and Jacobs Syndrome (Trisomy XYY) with Complete Tracheal Rings Deformity: Case Report and Literature Review

Down syndrome (DS, trisomy 21) with an extra copy of chromosome 21 is one of the most common aneuploidies in humans. Jacobs syndrome or XYY syndrome (trisomy XYY) with an extra copy of sex chromosome Y is a rare sex chromosome trisomy in males. Double aneuploidy (DA) with an extra copy of chromosome 21 and sex chromosome Y is an extremely rare occurrence. Most trisomy 21 results from nondisjunction during maternal oocyte meiosis-I, whereas trisomy XYY is results from nondisjunction during paternal spermatocyte meiosis-I. We present a case of natural conception premature newborn of 30.4 weeks gestational age who had a DS facial phenotype with extensive syndactyly on both hands and feet. Other multisystem congenital anomalies were discovered, including mal-aligned perimembranous ventricular septal defect, bicuspid aortic valve, Dandy-Walker malformation's tetra-ventriculomegaly, and a rare complete tracheal rings deformity (CTRD) with trachea stenosis. Prenatal amniocentesis and postnatal chromosomal karyotyping analysis detected 48, XYY, + 21 nontranslocation trisomy 21, and free-lying Y chromosome without translocation. The existence of DA is rarely reported in literature reviews. In this review, we will discuss the characteristics of DS and Jacobs syndrome as well as the associated multiorgan malformation including the rare lethal CTRD.

First Croatian Case of Double Aneuploidy: A Child With Klinefelter and Edwards Syndrome (48,XXY,+18) - Possible Causes and Contributing Factors

We report a case of double aneuploidy in a preterm male newborn with karyotype 48,XXY,+18 whose mother was of advanced age and infected with the SARS-CoV-2 virus during the early stages of her pregnancy. The clinical features observed in the newborn included intrauterine growth retardation, dysmorphic facial features, overlapping fingers on both hands, respiratory distress syndrome, ventricular septal defect, patent ductus arteriosus, persistent pulmonary hypertension, and bilateral clubfoot, a phenotype that mainly correlates with Edwards syndrome (trisomy 18). To our knowledge, this is the first reported case of double aneuploidy in Croatia. This paper provides a detailed description of the clinical presentation and treatment strategies used, with the aim of providing valuable data for future recognition and management of similar cases. Furthermore, we discuss the mechanisms of nondisjunction that might account for this rare form of aneuploidy.

A novel trophectoderm biopsy technique for all blastocyst stages

Purpose

This study was conducted to assess the effectiveness of a new trophectoderm (TE) biopsy method that does not require prior opening of the zona pellucida at the blastocyst stage.

Methods

TE biopsy was conducted using a modified extrusion method for embryos during the cleavage stage. In this method, culture medium was injected into the perivitelline space to help extrude TE cells from the zona pellucida before TE biopsy.

Results

Our extrusion method preserves the embryo culture environment until immediately before biopsy because it does not require opening of the zona pellucida prior to TE biopsy. Furthermore, this method does not require a waiting time for blastocyst hatching after laser irradiation, thereby minimizing damage to the embryos and maintaining the time schedule of culture operations.

Conclusions

TE biopsy using this novel extrusion method may be useful in various applications, including the collection of TE cells for next-generation sequencing analysis.

Comparative clinical genetic testing in spontaneous miscarriage: Insights from a study in Southern Chinese women

Single nucleotide polymorphism (SNP) array and karyotype analyses were conducted on 441 spontaneous miscarriage placental villous tissues collected from women from southern China. Subsequently, the results from these two analyses were compared to evaluate the best diagnostic strategy for subsequent pre‐pregnancy planning. Here, the success rate of genetic testing using karyotyping and SNP array analysis was 78.46% (346/441) and 100.0% (441/441), respectively. The abnormality rate estimated by both methods was 54.9% (242/441). Three hundred and forty‐six cases were successfully detected via both SNP array and karyotype analyses; the rate of consistent detection was 96.24% (333/346), whereas 13 cases were not consistent. There was no substantial positive correlation between age and genetic abnormalities such as Turner syndrome, structural variation or euploidy state in the different age groups studied. However, the aneuploidy rate was significantly different in each age group. Thus, although SNP array has higher success rate and resolution in genetic abnormality detection, supplementary karyotype analysis is needed for a more accurate revelation of the genetic aetiology of miscarriages. Therefore, this study indicates that simultaneous karyotype and SNP array analyses should be performed for spontaneous miscarriages. Furthermore, miscarriages irrespective of maternal age must be genetically analysed.

Clinical utilization of chromosomal microarray analysis for the genetic analysis in subgroups of pregnancy loss

OBJECTIVE

The underlying etiologies of pregnancy loss are heterogeneous and in many cases unexplained. This study was to explore the genetic causes of early and late pregnancy loss using chromosomal microarray analysis (CMA).

METHODS

A cohort of 222 specimens of conceptions underwent genetic analysis using Affymetrix CytoScan 750 K arrays, which includes both SNP markers and copy number markers.

RESULTS

Of the 222-products of conception (POC), the overall detection rate for clinical significantly chromosomal anomalies was 40.54%, including 53 autosomal aneuploidy (23.87%), 16 sex chromosome aneuploidy (7.21%), 5 mutiple aneuploidy (2.25%), 4 triploidy (1.80%), and 12 pathogenic copy number variants (pCNVs) (5.41%). In addition, variants of uncertain significance and loss of heterozygosity were detected in 9 samples and 2 samples, respectively. The detection rates for total chromosomal abnormalities, autosomal aneuploidy, sex chromosome aneuploidy, multiple aneuploidy, and triploidy in specimens of early pregnancy loss was higher than that of late pregnancy loss, while had lower detection rate of pCNVs. Moreover, the detection rate in POC of mothers younger than 35 years was lower than that of advanced maternal age. The detection rate was 40.57% in POC of mothers with adverse pregnancy histories, in which was comparable with that of mothers without adverse pregnancy histories.

CONCLUSIONS

CMA yielded a superior detection rate in early pregnancy loss than that of late pregnancy loss. Moreover, the incidence of chromosome abnormality in cases with advanced maternal age was higher than that of cases with younger maternal age, while adverse pregnancy history seemed not to be the factors affecting the detection rate for chromosomal abnormality in pregnancy loss.

Karyotype evaluation of repeated abortions in primary and secondary recurrent pregnancy loss

PURPOSE

To study the contribution of embryo chromosomal abnormalities in primary and secondary recurrent pregnancy loss (RPL) and to analyze the recurrence of chromosomal constitution in miscarriages from the same couple.

METHODS

Retrospective study of abortion karyotypes in RPL families based on the mother's primary or secondary RPL status (563 embryo specimens, 335 samples from primary, and 228 samples from secondary RPL). RPL was defined as two or more consecutive miscarriages. One hundred eight cases of recurrent embryo/fetal loss in 51 families were analyzed to assess the probability of having the same karyotype pattern (recurrent normal or recurrent abnormal) in both previous and subsequent pregnancy loss. The karyotypes of abortions were established using standard cytogenetic analysis, as well as interphase fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH).

RESULTS

The frequency of aberrations was 43.9% in abortions from primary RPL versus 52.6% in secondary RPL (p = 0.041). Women 35 years of age or older were the main contributors to this difference. The odds ratio of a subsequent abortion having the same karyotype pattern (normal or abnormal) as the previous one was 6.98 (p = 0.0013).

CONCLUSION

The frequency of abnormalities is higher in abortions from the secondary RPL versus primary RPL group, and this difference is due to the relative deficiency of miscarriages with abnormal karyotypes in older women with primary RPL. The probability of having the same karyotype pattern (recurrent normal or recurrent abnormal) in the previous and subsequent abortion is increased significantly compared with chance.

Investigation of chromosomal alterations in patients with Alzheimer's disease in the state of Amazonas, Brazil

OBJECTIVES

Alzheimer's disease (AD) has as its main characteristic the deterioration of cerebral functions. Its etiology is still complex and undefined despite the progress made in understanding its neurological, infectious, biochemical, genetic and cytogenetic mechanisms.

METHODS

Considering this, the aim of this study was to investigate the presence of chromosomal alterations in the peripheral blood lymphocytes, and to verify if there was a high frequency of these alterations in patients diagnosed with AD at the University Hospital GetúLio Vargas Outpatient Clinic Araújo Lima in Manaus, Amazonas, Brazil.

RESULTS

Among the nine patients in the AD group, only one patient did not have metaphases with chromosomal alterations (2n = 46,XX), while eight patients with AD showed numerical chromosomal alterations, classified as X chromosome aneupLoidy (2n = 45,X) and double aneupLoidy (2n = 44,X,-X,-10; 2n = 44,X,-X,-13 and 2n = 44,X,-X,-21).

CONCLUSION

In the control group, no chromosomal changes were found in the karyotypes of these individuals. Therefore, the karyotypes of patients with AD undergo chromosomal alterations at different levels. These findings are being described for the first time in the population of Amazonas, and they highlight the importance of the inclusion of cytogenetic investigations in the routine management of patients with AD.

What should we consider in the case of combined Down- and 47,XY,+i(X)(q10) Klinefelter syndromes? The unique case of a male newborn and review of the literature

Background

Double aneuploidies - especially in combination with structural aberrations - are extremely rare among liveborns. The most frequent association is that of Down (DS) and Klinefelter syndromes (KS). We present the case of a male newborn with a unique 47,XY,+ 21[80%]/48,XY,+i(X)(q10),+ 21[20%] karyotype, hypothesize about his future phenotype, discuss the aspects of management and review the literature.

Case presentation

The additional association of isochromosome Xq (i(X)(q10)) could be the result of a threefold non-disjunction event. 47,XY,+i(X)(q10) KS is not common and its symptoms differ from the classical KS phenotype. In combined DS and i(X)(q10) KS, the anticipatory phenotype is not simply the sum of the individual syndromic characteristics. This genotype is associated with higher risk for several diseases and certain conditions with more pronounced appearance: emotional and behavioral disorders; poorer mental and physical quality of life; lower muscle mass/tone/strength; connective tissue weakness; muscle hypotonia and feeding difficulties; osteopenia/−porosis with earlier beginning and faster progression; different types of congenital heart diseases; more common occurrence of hypertension; increased susceptibility to infections and female predominant autoimmune diseases; higher risk for hematological malignancies and testicular tumors.

Conclusions

In multiple aneuploidies, the alterations have the potential to weaken or enhance each other, or they may not have modifying effects at all. Prenatal ultrasound signs are not obligatory symptoms of numerous chromosomal anomalies (specifically those involving supernumerary sex chromosomes), therefore combined prenatal screening has pertinence in uncomplicated pregnancies as well.

A multiplex droplet digital PCR assay for non-invasive prenatal testing of fetal aneuploidies

Higher multiplexing in droplet digital PCR (ddPCR) can simplify the detection process of ddPCR-based non-invasive prenatal testing (NIPT) and improve its reliability, making it a practical approach in clinical practice. However, a high level of multiplex ddPCR-based NIPT has rarely been reported. In this study, we developed a multiplex ddPCR assay using universal locked nucleic acid (LNA) probes to reliably identify fetal aneuploidies. We first performed statistical analysis based on the Poisson distribution to evaluate the required number of target DNA molecules and the total number of droplets for a ddPCR assay. Next, we designed two sets of primers and probes to quantify cfDNA from chromosomes 21 and 18 and then determined the disease status of a sample. Finally, we evaluated our multiplex ddPCR assay with 60 clinical plasma samples. All of the 60 clinical samples were correctly identified. The accessibility and cost-effectiveness of our multiplex ddPCR-based NIPT make it a competitive prenatal testing method in clinical use.

Chromosomal abnormalities in products of conception of first-trimester miscarriages detected by conventional cytogenetic analysis: a review of 1000 cases

PURPOSE

The purpose of this study is to perform a retrospective analysis of types and frequencies of chromosomal abnormalities detected by conventional cytogenetic studies in first-trimester miscarriages after spontaneous conception and IVF.

METHODS

Standard cytogenetic analysis of GTG-banded chromosomes obtained from products of conception (POCs): semi-direct and short-term cultured chorionic villi or long-term cultured fetal mesodermal cells.

RESULTS

50.1% of first-trimester miscarriages in the studied group had chromosomal abnormalities: 59.7% of trisomies, 22% of poliploidies, 7.5% of monosomies, 7% of unbalanced structural abnormalities, and 3.8% of multiple aneuploidies. An increase in the frequency of chromosomally abnormal miscarriages was observed in the group of women above 40 when compared to groups of women under 35 (P < 0.05). No difference in frequencies and types of chromosomal abnormalities in POCs of miscarriages after ICSI and spontaneous conception was observed.

CONCLUSIONS

Approximately, 50% of first-trimester miscarriages have chromosomal abnormalities which can be detected by conventional cytogenetic analysis. The presence of chromosomal abnormality may explain the cause of miscarriage, improving the reproductive counseling and planning.

Double Aneuploidy Detected by Cell-Free DNA Testing and Confirmed by Fetal Tissue Analysis

BACKGROUND

Double aneuploidies account for 0.21-2.8% of spontaneous abortions resulting from chromosomal abnormalities. Rarely, cell-free DNA testing detects multiple aneuploidies; however, to discern among maternal, placental, and fetal origin, further evaluation is required.

CASE

A 49-year-old woman, gravida 5 para 0, underwent cell-free DNA testing at 11 4/7 weeks of gestation, which revealed a fetus that was high risk for trisomies 18 and 21. On ultrasonography at 14 weeks of gestation, she was diagnosed with a missed abortion and underwent surgical management. Fetal and placental tissues were sent for analysis and were positive for trisomies 18 and 21, confirming the results of cell-free DNA testing.

CONCLUSION

Our case highlights the ability of cell-free DNA testing to recognize a double aneuploidy confirmed by fetal tissue analysis.

Follow-up of multiple aneuploidies and single monosomies detected by noninvasive prenatal testing: implications for management and counseling

Objectives

To determine the underlying biological basis for noninvasive prenatal testing (NIPT) results of multiple aneuploidies or autosomal monosomies.

Methods

Retrospective analysis of 113,415 tests to determine the study cohort, consisting of 138 (0.12%) cases reported as a single autosomal monosomy (n = 65), single trisomy with a sex chromosome aneuploidy (n = 36), or with multiple aneuploidies (n = 37). Clinical outcome information was reviewed and stratified into eight categories according to whether the karyotype or sonographic information agreed or disagreed with sequencing results.

Results

Of 67 cases with fetal or neonatal karyotypes available, 16 (24%) were partially or fully concordant with the NIPT result, 4 (6%) had aneuploidy on a reference chromosome, and 47 (70%) had normal fetal chromosomes, in which 5/47 had maternal malignancies reported. One case of maternal mosaic trisomy 8 was also detected. Of cases with no fetal karyotype information, ten had an abnormal clinical outcome, one was a normal live birth, and one reported maternal malignancy.

Conclusions

Noninvasive prenatal test results of autosomal monosomy or multiple aneuploidies are rare but have a diversity of underlying biologic causes. Some reflect the fetal karyotype; some reflect the presence of other maternal or fetal chromosome abnormalities, and a small number are linked to maternal disease. © 2016 Illumina. Prenatal Diagnosis published by John Wiley & Sons, Ltd.

What's already known about this topic?

Noninvasive prenatal testing (NIPT) has been validated for common autosomal trisomies (trisomy 21, 18, and 13), sex chromosome aneuploidies, and a selection of microdeletion syndromes.

NIPT findings that are discordant with the fetal karyotype can be because of biological reasons, such as confined placental mosaicism, maternal chromosome abnormalities, and other maternal conditions such as occult malignancy.

What does this study add?

Clinical and karyotype outcome information for cases that received an NIPT result indicating an autosomal monosomy or multiple aneuploidies. Some autosomal monosomy and multiple aneuploidy results reflect the true fetal karyotype, and some are explained by other factors, such as other fetal or maternal chromosomal abnormalities or maternal disease.

This information will help providers with post‐test counseling for these rare and unusual results.