Prevalence of chromosomal abnormalities in couples with recurrent miscarriage

Cytogenetic analysis of 3488 patients with recurrent pregnancy loss: An experience of two decades from a tertiary care center in South India

Background

Recurrent pregnancy loss (RPL) affects approximately 15-20% of couples. Constitutional chromosomal abnormalities (CA) are an important cause of RPL because the gametes of carriers may have chromosomal imbalance which is lethal to the fetus. Therefore, the identification of CA helps to provide information about likely outcome of pregnancy in carriers. The objective of this study was to determine the frequency and types of CA in RPL.

Methods

The study group consisted of individuals with RPL seen at a tertiary care center in South India from 2001 to 2019, whose karyotypes were reviewed retrospectively. Cytogenetic analysis was performed on peripheral blood using standard protocols. The number of metaphases analyzed per patient was 20 and extended up to 50 for confirmation of low-level mosaicism.

Results

There were 3488 individuals (1663 couples and 162 where only partner was tested of whom 104 were females). The frequency of CA was 3.6% (127/3488) (M:F ratio of 1:2.6). Structural aberrations were seen in 2.5% (90/3488) and numerical aberrations of sex chromosomes in 1.1% (37/3488) of patients. Structural aberrations included 68 balanced translocations including one three-way translocation, seven inversions, one insertion and duplication each, and 14 Robertsonian translocations. There was one patient each with Turner syndrome (TS) and 47,XYY syndrome. We had 37 mosaics, comprising 29 with mosaic TS and 6 with triple X mosaicism and 2 with mosaicism for balanced translocation.

Conclusion

The frequency of CA is comparable to the literature. We have described a few less commonly seen aberrations as well as sex chromosomal aneuploidies, almost all of which were due to low-level mosaicism.

Chromosomal abnormalities of 19,000 couples with recurrent spontaneous abortions: a multicenter study

OBJECTIVE

To investigate the demographic data and karyotypes of 19,000 couples who experienced recurrent spontaneous abortion (RSA).

DESIGN

A cross-sectional study of 19,000 couples.

SETTING

Five hospitals.

PATIENT(S)

A total of 19,000 couples experiencing RSA.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

Cytogenetic analysis of blood lymphocytes.

RESULT(S)

A total of 844 couples (4.44%) showed chromosomal aberrations in either partner. Females were more likely to have chromosomal aberrations. The mean age of females and males with chromosomal aberrations was younger than that of females and males without chromosomal aberrations. Interestingly, sex and age distribution varied significantly depending on the subtypes of chromosomal aberrations. We detected 324 balanced translocations, including 223 novel ones. They were distributed across all chromosomes; the frequency of balanced translocations decreased according to the numerical order of autosomes (strong negative correlation; r = -0.84). Individuals with balanced translocations were younger than other groups. All 58 inversions, including 25 novel ones, were detected in autosomes; the negative correlation also existed. Thirteen Robertsonian translocations, 5 deletions, and 3 duplications were detected. Six types of Turner variants, triple X mosaicism, and mosaic Down syndrome were detected in females; Klinefelter variants and mosaic XYY syndrome were detected in males. Marker chromosomes at various mosaic levels and 7 different complex chromosomal rearrangements were also observed.

CONCLUSION(S)

Patients who experienced RSA induced by chromosomal aberrations experienced miscarriages at a younger age. Significant correlations existed between the patients' age or sex and the subtypes of chromosomal aberrations. This study detected several chromosomal abnormalities associated with RSA, including various novel aberrations.

Cytogenetic Screening in Couples with Recurrent Pregnancy Loss: A Single-Center Study and Review of Literature

Context:

Recurrent pregnancy loss (RPL) is a devastating reproductive problem that affects more than 2% of couples who are trying to conceive. Chromosomal rearrangements in either carrier are a major cause of clinically recognized abortion.

Aims:

The purpose of this study is to report the prevalence of chromosome abnormalities in RPL and provide clinical characteristics of couples with two and more miscarriages.

Settings and Design:

Genetic counseling in laboratory of histology housed in a Faculty of Medicine of Sfax.

Materials and Methods:

Karyotype was generated from the peripheral blood lymphocyte cultures and the cytogenetic analysis was performed using R-bands after heat denaturation and Giemsa (RHG) banding. A multiplex polymerase chain reaction wherever necessary was done.

Statistical Analysis Used:

SPSS version 17.

Results:

A total of 104 couples with RPL were carried out in this study. The frequency of chromosomal rearrangements was 11.5%, three times more prevalent in men than women (P = 0.08). In addition, the prevalence of chromosomal anomalies increases according to the number of miscarriages (from 4.8% to 7.6%, with 2 or ≥3 miscarriages, respectively; P = 0.9). Finally, a particular familial adverse reproductive background was found in these carriers (P = 0.03).

Conclusions:

These data highlight that an RPL evaluation is appropriate after the second miscarriage and that cytogenetic evaluation is necessary for an accurate approach to elucidate the causes of RPL. Moreover, familial adverse reproductive backgrounds have an impact of being carrier of chromosome abnormalities and a larger study is mandatory to define reproductive characteristics of carriers.

Chromosome Abnormalities Related to Reproductive and Sexual Development Disorders: A 5-Year Retrospective Study

Chromosomal abnormalities are the main genetic risk factor associated with reproductive and sexual development disorders (DSD). The goal of this study is to retrospectively evaluate the frequency of chromosomal aberrations in Moroccan subjects with problems of procreation or sexual ambiguity. A total of 1005 individuals, including 170 infertile couples, underwent cytogenetic analysis in the Cytogenetic Laboratory of the Pasteur Institute of Morocco. Heparinized blood samples were processed according to the standard karyotype method. A total (81.5%) of the patients studied had a normal karyotype, while the remaining (18.5%) patients had an abnormal karyotype. Female patients had more chromosomal abnormalities (52%) than male patients (48%). These chromosomal aberrations included 154 cases (83%) of sex chromosomal abnormalities, the most common being Turner's syndrome and Klinefelter's syndrome, and 31 cases (17%) had autosomal aberrations, especially chromosome 9 reversal (inv(9)(p12;q13)). The present data shows that among 170 couples, 10.6% had chromosomal abnormalities mainly involved in the occurrence of recurrent miscarriages. Genotype-phenotype correlations could not be made, and therefore, studies using more resolutive molecular biology techniques would be desirable.

Cytogenetic Analysis of 570 Couples with Recurrent Pregnancy Loss: Reporting 11 Years of Experience

Objectives

Recurrent pregnancy loss (RPL) is a serious complication of pregnancies, affecting almost 2%-5% of couples. Among numerous underlying causes, chromosomal anomalies in one of the partners are regarded as important issues, with varying frequencies among different populations. In this study, we aimed to determine the prevalence of chromosomal abnormalities and chromosome polymorphisms in couples with a history of RPL from Kermanshah province, west of Iran.

Materials and Methods

In this 11-year retrospective study, a total of 1140 cases with two or more spontaneous abortions were recruited and studied according to standard cytogenetic analysis.

Results

From a total of 1140 reviewed blood samples, 1011 people (88.5%) had a normal karyotype and 129 people (11.5%) had chromosomal aberrations. These aberrations were found in 62 females and 67 males. The prevalence of chromosomal abnormalities was as follows: 18 (1.5%) structural aberrations, 1 numerical anomaly and 110 (9.6%) apparently normal polymorphic variants.

Conclusions

Our findings could determine the underlying cause of RPL in 1.5% of the population while the majority still remained unexplained. This emphasizes the importance of searching for other genetic and nongenetic causes of RPL in apparently idiopathic cases of RPL.

Weighted gene correlation network analysis reveals novel regulatory modules associated with recurrent early pregnancy loss

At present, the etiology and pathogenesis of recurrent early pregnancy loss (REPL) are not completely clear. Therefore, identifying the underlying diagnostic and prognostic biomarkers of REPL can provide new ideas for the diagnosis and treatment of REPL. The chip data of REPL (GSE63901) were downloaded from the NCBI Gene Expression Omnibus (GEO) database. Weighted Gene Co-Expression Network Analysis (WGCNA) was used to construct a co-expression module for studying the relationship between gene modules and clinical features. In addition, functional analysis of hub genes in modules of interest was performed. A total of 23 co-expression modules were identified, two of which were most significantly associated with three clinical features. The MEbrown module was positively correlated with cyclin E level and the out-of-phase trait while the MEred module was positively correlated with the effect of progesterone. We identified 17 hub genes in the MEred module. The functional enrichment analysis indicated that such hub genes were mainly involved in pathways related to cellular defense response and natural killer (NK) cell-mediated cytotoxicity. In the MEbrown module, we identified 19 hub genes, which were mainly enriched in cell adhesion molecule production, regulation of cellular response to growth factor stimulus, epithelial cell proliferation, and transforming growth factor-β (TGF-β) signaling pathway. In addition, the hub genes were validated by using other datasets and three true hub genes were finally obtained, namely DOCK2 for the MEred module, and TRMT44 and ERVMER34-1 for the MEbrown module. In conclusion, our results screened potential biomarkers that might contribute to the diagnosis and treatment of REPL.

Overexpression of lncRNA EPB41L4A-AS1 Induces Metabolic Reprogramming in Trophoblast Cells and Placenta Tissue of Miscarriage

Long non-coding RNAs (lncRNAs) have been shown to be crucial regulators in numerous human diseases. However, little is known about their effects on early recurrent miscarriage (RM). Here we aimed to investigate the role of lncRNA EPB41L4A-AS1 on placental trophoblast cell metabolic reprogramming, which might be involved in the pathogenesis of RM. After microarray and GEO database analyses, we found that EPB41L4A-AS1 was significantly increased in early RM placental tissue, and this increase may relate to estradiol-mediated upregulation of PGC-1α. EPB41L4A-AS1 overexpression inhibits glycolysis but increases the dependence on fatty acid oxidation in mitochondrion metabolism and suppresses the Warburg effect, which is necessary for rapid growth of the placental villus, leading to miscarriage. Mechanistic analyses demonstrated that EPB41L4A-AS1 functions as a lncRNA in the regulation of VDAC1 and HIF-1α expression through enhancement of H3K4me3 levels in the promoters of VDAC1 and HIF1A-AS1, a natural antisense transcript (NAT) lncRNA of HIF-1α. Taken together, these findings demonstrate that aberrant expression of EPB41L4A-AS1 is involved in the etiology of early RM, and it may be a candidate diagnostic hallmark and a potential therapeutic target for early RM treatment.

The analysis of chromosomal abnormalities in patients with recurrent pregnancy loss, focusing on the prognosis of patients with inversion of chromosome (9)

PURPOSE

Inversion of chromosome 9 (inv[9]) is considered to be a normal variant, and the inv(9) in patients or husbands with recurrent pregnancy loss (RPL) is believed to be harmless. However, there are few reports concerning the outcomes of pregnancy in patients with RPL when the patient or their partner has inv(9). In this study, we analyzed the outcomes of pregnancy in this patient population.

METHODS

Chromosomal karyotyping was performed for 2006 couples with RPL (two or more consecutive early pregnancy losses including non-visualized cases) with their informed consent. The frequency of various chromosomal abnormalities in the patient population was then analyzed, and the outcomes of pregnancy in patients with inv(9) were investigated.

RESULTS

The frequency of inv(9) in the overall population was 2.6% (52/2006). Thus far, 32 patients have conceived repetitively, resulting in live births in 23 cases and early pregnancy losses in nine cases. Four of the nine cases obtained a good outcome in the subsequent pregnancy. Thus, a successful outcome was obtained in 27 of the 32 (84.4%) cases.

CONCLUSIONS

This study suggests that inv(9) has no adverse influence on subsequent pregnancy.

The Frequency and Spectrum of Chromosomal Translocations in a Cohort of Sri Lankans

Translocations are the most common type of structural chromosomal abnormalities. Unbalanced translocations are usually found in children who present with congenital abnormalities, developmental delay, or intellectual disability. Balanced translocations are usually found in adults who frequently present with reproductive failure; either subfertility, or recurrent pregnancy loss. Herein, we report the spectrum and frequency of translocations in a Sri Lankan cohort. A database of patients undergoing cytogenetic testing was maintained prospectively from January 2007 to December 2016 and analyzed, retrospectively. A total of 15,864 individuals were tested. Among them, 277 (1.7%) had translocations. There were 142 (51.3%) unbalanced translocations and 135 (48.7%) balanced translocations. Majority (160; 57.8%) were Robertsonian translocations. There were 145 (52.3%) children and adolescents aged less than 18 years with translocations, and 142 (97.9%) were unbalanced translocations. Majority [138 (95.2%)] were referred due to congenital abnormalities, developmental delay, or intellectual disability, and 91 were children with translocation Down syndrome. All adults aged 18 years or above (132) had balanced translocations. Subfertility and recurrent pregnancy loss [84 (63.6%)] and offspring(s) with congenital abnormalities [48 (36.4%)] were the most common indications in this group. Majority (68.2%) in this group were females with reciprocal translocations (55.3%). Chromosomes 21, 14, and 13 were the most commonly involved with rob(14q21q) [72 (26%)], rob(21q21q) [30 (13.7%)], and rob(13q14q) [34 (12.3%)] accounting for 52% of the translocations. Chromosomes 1, 8, 11, and 18 were most commonly involved in reciprocal translocations. The observed high frequency of chromosomal translocations in our cohort highlights the importance of undertaking cytogenetic evaluation and providing appropriate genetic counseling for individuals with the phenotypes associated with these translocations.

Chromosomal abnormalities in couples with recurrent spontaneous miscarriage: a 21-year retrospective study, a report of a novel insertion, and a literature review

PURPOSE

The aim of this study is to evaluate the frequency and nature of chromosomal abnormalities in Moroccan couples with recurrent spontaneous miscarriage (RSM). In addition, the data were compared with those reported elsewhere in order to give a global estimation of chromosomal abnormalities frequencies.

METHODS

The study was performed for all couples with RSM who were referred to the cytogenetic department, Pasteur Institute of Morocco, from different hospitals in Morocco between 1996 and 2016. Cytogenetic analysis was performed according to the standard method.

RESULTS

Among 627 couples with RSM, the chromosomal abnormalities were identified in 11.00% of couples, with chromosomal inversions in 4.30%, reciprocal translocations in 2.71%, Robertsonian translocations in 1.43%, and deletion, isochromosome, and insertion in 0.15% each. The insertion identified [46,XX,ins(6)(p24q21q27)] is new, and is the fourth reported in association with RSM. The mosaic karyotypes were observed in 0.64%, polymorphic variants were identified in 1.27%, and numerical aneuploidy was observed in 0.15%. In regrouping our results with those in 27 other studies already published in 21 different countries, we obtained the frequency of chromosomal abnormalities in couple with RSM to be 5.16% (991/19197 couples). The reciprocal translocation was the most frequent with 2.50%, followed by Robertsonian translocation 0.83% and inversions 0.77%. The other types of chromosomal abnormalities were present with 0.98% in the world.

CONCLUSION

This data showed that the frequency of chromosomal abnormalities in Moroccan couples with RSM is 11.00%, and in regrouping our results with other studies, the frequency changes to 5.16%.

Cytogenetic abnormalities in couples with a history of primary and secondary recurrent miscarriage: a Brazilian Multicentric Study

Objective: To evaluate the difference between chromosomal abnormalities between the gender of couples affected by Recurrent miscarriage (RM) and if there is an association between previous obstetric history and chromosomal abnormalities of the parents.Methods: Multicenter, retrospective, observational study from seven different RM clinics between 2006 and 2016. We enrolled 707 couples (1014 participants) with a history of RM. We compared the frequency of chromosomal abnormalities between groups of couples with primary and secondary RM and separated between women and their partners. Furthermore, we compared the prevalence of chromosomal abnormalities between groups based on the number of previous spontaneous abortions.Results: The overall prevalence of all cytogenetic abnormalities was 5.59% (n = 1414, women and their partners). Excluding cases of polymorphism and inversion of chromosome 9, which are considered variants of normality, the prevalence in all individuals was 2.26% (n = 32/1414). The comparative analysis of cases of chromosomal abnormalities among couples with primary and secondary RM based on the number of previous miscarriages (PM) revealed a similar frequency between groups. The statistical analysis of the total cases (primary PM + secondary PM) in these three groups were as follows: (a) couple, 2 pm versus 3 pm vs. ≥4 PM, p = .514; (b) women, 2 pm versus 3 pm vs. ≥4 PM, p = .347; and (3) partner, 2 pm versus 3 pm vs. ≥4 PM, p = .959. Chromosomal abnormalities were significantly more prevalent among women than among their partners (6.9 versus 4.2%; p = .027). Moreover, the distribution of leading chromosomal abnormalities among women was different compared with their partners. Among women, we observed these abnormalities in the following frequency order: mosaicism (38.8%), polymorphism (32.6%), translocation (16.3%), and inversion (12.3%). Among their partners, these abnormalities were polymorphism (73.3%), inversion (13.3%), mosaicism (6.7%), and translocation (6.7%).Conclusion: The number of PM and the history of full-term pregnancy does not correlate with an increase or decrease in the prevalence of cytogenetic abnormalities in couples with RM.

Chromosomal Aberrations in Couples with Pregnancy Loss: A Retrospective Study

BACKGROUND

Recurrent pregnancy loss is a challenging reproductive problem, and chromosomal anomalies approximately affect 2%-8% of couples with recurrent pregnancy loss. The chromosomal abnormality, especially balanced translocation rearrangement in either parent, is the important cause of recurrent spontaneous abortion.

AIMS

The aim of this study was to investigate the role and prevalence of chromosomal anomalies in recurrent miscarriages. The results will be helpful for counseling and make the decision for alternative options and precaution for the affected couples and also support to make a national database.

SETTINGS AND DESIGN

The present retrospective study was carried out in 172 couples (344 individuals) having the history of three or more recurrent spontaneous abortion. The cytogenetic analysis was done in all 344 individuals using G-banding and karyotyping.

RESULTS

Out of 172 couples, 17 couples (9.88%) had different types of structural or numerical chromosomal abnormalities. The structural aberrations were observed in 15 (8.72%) couples, and numerical aberrations were seen in 2 (1.16%) couples. Out of 17 couples, 8 (47.05%) had balanced translocations, 2 (11.76%) had the Robertsonian translocation, 5 (29.41%) had the pericentric inversion of chromosome 8, 9, and Y, and only 2 (11.76%) women showed sex chromosome numerical aberrations.

CONCLUSIONS

Cytogenetic analysis should be an important routine investigation in couples with repeated miscarriages. Cytogenetic analysis is essential and helpful for genetic counseling to take precaution and implementing proper reproductive alternatives. Studies on the genetic basis of pregnancy loss should be taken up to generate data on these issues from different regions.

Chromosomal abnormalities in recurrent miscarriages by conventional karyotyping analysis

Abstract Objectives: to describe the prevalence and types of chromosomal abnormalities in couples with recurrent miscarriage and products of conception. Methods: electronic searches were performed in the PubMed/Medline database and in the Portal Regional da Biblioteca Virtual em Saúde/BVS (Regional Website of the Virtual Library in Health/BVS) using the descriptors “chromosomal abnormalities and abortions and prevalence”. After applying the inclusion and exclusion criterias, 17 studies were selected. Results: 11 studies were conducted in couples with recurrent miscarriage and six in products of conception. The main results of the couples with recurrent miscarriage were: the frequency of chromosomal abnormalities which varied from 1.23% to 12% and there was a predominance alteration of the chromosomal structures (reciprocal translocations, followed by Robertsonian). In products of conception, the results observed were: the frequency of chromosomal abnormality was above 50% in approximately 70% of the studies; there was a predominance alteration of the numerical chromosomal (trisomy - chromosomes 16, 18, 21 and 22, followed by polyploidy and monosomy X). Conclusions: in summary, cytogenetic alterations represent an importante cause of pregnancy loss and its detection can help couples with genetic counseling. Therefore, the value of knowledge on the prevalence of cytogenetic abnormalities in miscarriage samples is unquestionable, once it is permitted a proper genetic counseling for the couple.

A Study on Balanced Chromosomal Translocations in Couples with Recurrent Pregnancy Loss

Background:

Recurrent pregnancy loss (RPL) is an obstetric complication that affects couples in their reproductive age. Chromosomal abnormalities, mainly balanced rearrangements, could commonly be present in couples with RPL.

Aim:

The purpose of this study is to evaluate the contribution of chromosomal abnormalities and balanced reciprocal translocations, in particular occurring in either of the partners, resulting in RPL.

Materials and Methods:

A retrospective cytogenetic study was carried out on 152 individuals (76 couples) having a history of RPL. The cases were analyzed using G-banding and fluorescence in situ hybridization, wherever necessary.

Results:

Chromosomal abnormalities were observed in 3.2% of the total RPL cases, of which balanced translocations were observed in 4 (80%) individuals and marker chromosome was detected in 1 (20%) individual. All balanced translocations comprised reciprocal translocations, and no cases of Robertsonian translocations were detected in our study. Among reciprocal translocation carriers, three were male and one was female. Polymorphic variants were noted in 8 (5.3%) individuals.

Conclusions:

Chromosomal analysis is an important etiological investigation in couples with RPL. Balanced translocations are the most commonly detected chromosomal abnormalities in such couples. Thus, these couples are the best candidates for offering prenatal genetic diagnosis, thereby ensuring a better reproductive outcome.

Chromosomal abnormalities in 163 Tunisian couples with recurrent miscarriages

Recurrent miscarriage (RM) is defined as three or more consecutive pregnancy losses before 24 weeks of gestation. Parental chromosomal abnormalities represent an important etiology of RM. The aim of the present study was to identify the distribution of chromosome abnormalities among Tunisian couples with RM referred to the Department of Cytogenetic at the Pasteur Institute of Tunis (Tunisia) during the last five years. Standard cytogenetic analysis was carried out in a total of 163 couples presenting with two or more spontaneous abortions. Karyotypes were analyzed by R-banding. We identified 14 chromosomal abnormalities including autosomal reciprocal translocation, Robertsonian translocation, inversion, mosaic aneuploidy and heteromorphysm. The overall prevalence of chromosomal abnormalities was 8.5% in our cohort. This finding underlies the importance of cytogenetic investigations in the routine management of RM.

Cytogenetic analysis in couples with recurrent miscarriages: a retrospective study from Punjab, north India

Human reproduction is considered as the most inefficient event as ~15-20% of human pregnancies end in miscarriage and in the product of miscarriages, chromosomal anomalies are a common occurrence. The aim of the present retrospective study was to assess the frequency of chromosomal aberrations in couples with recurrent miscarriages in the region of Punjab and to compare with worldwide frequencies. In this study, a total of 440 cases were referred between the period 1995-2015. After lymphocyte culturing, giemsa-trypsin banding was done for each case to assess the chromosomal anomalies. The frequency of chromosomal aberrations among couples was found to be 3.41% in our study. Among these aberrations, balanced reciprocal translocations formed the largest group with 60% anomalies. We would conclude that clinicians should understand the importance of chromosomal analysis in these couples and refer them for karyotyping after two miscarriages to rule out the possible genetic cause of recurrent miscarriages.

Associations of recurrent miscarriages with chromosomal abnormalities, thrombophilia allelic polymorphisms and/or consanguinity in Saudi Arabia

BACKGROUND

Recurrent pregnancy loss (RPL) or recurrent spontaneous abortion is an obstetric complication that affects couples at reproductive age. Previous reports documented a clear relationship between parents with chromosomal abnormalities and both recurrent miscarriages and infertility. However, limited data is available from the Arabian Peninsula which is known by higher rates of consanguineous marriages. The main goal of this study was to determine the prevalence of chromosomal abnormalities and thrombophilic polymorphisms, and to correlate them with RPL and consanguinity in Saudi Arabia.

METHODS

Cytogenetic analysis of 171 consent patients with RPL was performed by the standard method of 72-h lymphocyte culture and GTG banding. Allelic polymorphisms of three thrombophilic genes (Factor V Leiden, Prothrombin A20210G, MTHFR C677T) were performed using PCR-RFLP (restriction fragment length polymorphism) and gel electrophoresis.

RESULTS

Data analysis revealed that 7.6 % of patients were carrier of numerical or structural chromosomal abnormalities. A high rate of translocations (46 %) was associated to increased incidence of RPL. A significant correlation between consanguineous RPL patients and chromosomal abnormalities (P < 0.05) was found. Both Factor V Leiden and Prothrombin A20210G allelic polymorphisms were significantly associated with a higher prevalence of RPL.

CONCLUSIONS

This study demonstrated a strong association between RPL and the prevalence of chromosomal abnormalities and inherited thrombophilia. Given the high rate of consanguineous marriages in the Saudi population, these results underline the importance of systematic cytogenetic investigation and genetic counseling preferably at the premarital stage or at least during early pregnancy phase through preimplantation genetic diagnosis (PGD).

Impaired function of trophoblast cells derived from translocated hESCs may explain pregnancy loss in women with balanced translocation (11;22)

PURPOSE

The aim of the study was to study whether the trophoblasts carrying unbalanced translocation 11,22 [t(11;12)] display abnormal expression of trophoblastic genes and impaired functional properties that may explain implantation failure.

METHODS

t(11;22) hESCs and control hESCs were differentiated in vitro into trophoblast cells in the presence of BMP4, and trophoblast vesicles (TBVs) were created in suspension. The expression pattern of extravillous trophoblast (EVT) genes was compared between translocated and control TBVs. The functional properties of the TBVs were evaluated by their attachment to endometrium cells (ECC1) and invasion through trans-well inserts.

RESULTS

TBVs derived from control hESCs expressed EVT genes from functioning trophoblast cells. In contrast, TBVs differentiated from the translocated hESC line displayed impaired expression of EVT genes. Moreover, the number of TBVs that were attached to endometrium cells was significantly lower compared to the controls. Correspondingly, invasiveness of trophoblast-differentiated translocated cells was also significantly lower than that of the control cells.

CONCLUSIONS

These results may explain the reason for implantation failure in couple carriers of t(11;22). They also demonstrate that translocated hESCs comprise a valuable in vitro human model for studying the mechanisms underlying implantation failure.

Evaluation of 1100 couples with recurrent pregnancy loss using conventional cytogenetic, PGD, and PGS: hype or hope

Recurrent pregnancy loss (RPL) is an important clinical problem, mostly resulting from chromosomal or genetic defects, while in 30-60% of cases, it is idiopathic. The aim of this study is to evaluate the frequency and types of chromosomal abnormalities, also pre-implantation genetic diagnosis (PGD) and pre-implantation genetic screening (PGS) outcomes among Iranian couples with RPL. This retrospective study was conducted on 1100 Iranian couples (2200 individuals) with RPL referred to Royan Institute between 2008 and 2014. Karyotyping had been performed using standard cytogenetic techniques. PGD results of RPL patients with abnormal karyotypes and PGS results of RPL patients with normal karyotypes were also analyzed. The frequency of chromosomal abnormalities in these patients was 4.95%. Women demonstrated more abnormalities (6.82%) in comparison to men (3.09%). The successful rate of pregnancy after PGD and PGS was 52 and 18.64%, respectively. The observation of 4.95% chromosomal abnormalities among the patients with RPL could support this hypothesis that there is a direct relationship between chromosomal abnormalities and RPL. More than half of the patients who underwent PGD had successful pregnancy; therefore, this approach can improve the success rate of pregnancy in them. The results of PGS cycles showed that this technique could increase the live birth rate in RPL patients.

Chromosomal analysis of couples with repeated spontaneous abortions in northeastern iran

Background

Cytogenetic study of reproductive wastage is an important aspect in determining the genetic background of early embryogenesis. Approximately 15 to 20% of all pregnancies in humans are terminated as recurrent spontaneous abortions (RSAs). The aim of this study was to detect chromosome abnormalities in couples with RSAs and to compare our results with those reported previously.

Materials and Methods

In this retrospective study, the pattern of chromosomal aberrations was evaluated during a six-year period from 2005 to 2011. The population under study was 728 couples who attended genetic counseling services for their RSAs at Pardis Clinical and Genetics Laboratory, Mashhad, Iran.

Results

In this study, about 11.7% of couples were carriers of chromosomal aberrations. The majority of abnormalities were found in couples with history of abortion, without stillbirth or livebirth. Balanced reciprocal translocations, Robertsonian translocations, inversions and sex chromosome aneuploidy were seen in these cases. Balanced reciprocal translocations were the most frequent chromosomal anomalies (62.7%) detected in current study.

Conclusion

These findings suggest that chromosomal abnormalities can be one of the important causes of RSAs. In addition, cytogenetic study of families who experienced RSAs may prevent unnecessary treatment if RSA are caused by chromosomal abnormalities. The results of cytogenetic studies of RSA cases will provide a standard protocol for the genetic counselors in order to follow up and to help these families.

Human embryonic stem cells carrying an unbalanced translocation demonstrate impaired differentiation into trophoblasts: an in vitro model of human implantation failure

Carriers of the balanced translocation t(11;22), the most common reciprocal translocation in humans, are at high risk of creating gametes with unbalanced translocation, leading to repeated miscarriages. Current research models for studying translocated embryos and the biological basis for their implantation failure are limited. The aim of this study was to elucidate whether human embryonic stem cells (hESCs) carrying the unbalanced chromosomal translocation t(11;22) can provide an explanation for repeated miscarriages of unbalanced translocated embryos. Fluorescent in situ hybridization and karyotype analysis were performed to analyze the t(11;22) in embryos during PGD and in the derived hESC line. The hESC line was characterized by RT-PCR and FACS analysis for pluripotent markers. Directed differentiation to trophoblasts was carried out by bone morphogenetic protein 4 (BMP4). Trophoblast development was analyzed by measuring β-hCG secretion, by β-hCG immunostaining and by gene expression of trophoblastic markers. We derived the first hESC line carrying unbalanced t(11;22), which showed the typical morphological and molecular characteristics of a hESC line. Control hESCs differentiated into trophoblasts secreted increasing levels of β-hCG and concomitantly expressed the trophoblast genes, CDX2, TP63, KRT7, ERVW1, CGA, GCM1, KLF4 and PPARG. In contrast, differentiated translocated hESCs displayed reduced and delayed secretion of β-hCG concomitant with impaired expression of the trophoblastic genes. The reduced activation of trophoblastic genes may be responsible for the impaired trophoblastic differentiation in t(11;22)-hESCs, associated with implantation failure in unbalanced t(11;22) embryos. Our t(11;22) hESCs are presented as a valuable human model for studying the mechanisms underlying implantation failure.

Chromosomal abnormalities in couples with repeated fetal loss: An Indian retrospective study

BACKGROUND

Recurrent pregnancy loss is a common occurrence and a matter of concern for couples planning the pregnancy. Chromosomal abnormalities, mainly balanced rearrangements, are common in couples with repeated miscarriages.

PURPOSE

The purpose of this study is to evaluate the contribution of chromosomal anomalies causing repeated spontaneous miscarriages and provide detailed characterization of a few structurally altered chromosomes.

MATERIALS AND METHODS

A retrospective cytogenetic study was carried out on 4859 individuals having a history of recurrent miscarriages. The cases were analyzed using G-banding and fluorescence in situ hybridization wherever necessary.

RESULTS

Chromosomal rearrangements were found in 170 individuals (3.5%). Translocations were seen in 72 (42.35%) cases. Of these, reciprocal translocations constituted 42 (24.70%) cases while Robertsonian translocations were detected in 30 (17.64%) cases. 7 (4.11%) cases were mosaic, 8 (4.70%) had small supernumerary marker chromosomes and 1 (0.6%) had an interstitial microdeletion. Nearly, 78 (1.61%) cases with heteromorphic variants were seen of which inversion of Y chromosome (57.70%) and chromosome 9 pericentromeric variants (32.05%) were predominantly involved.

CONCLUSIONS

Chromosomal analysis is an important etiological investigation in couples with repeated miscarriages. Characterization of variants/marker chromosome enable calculation of a more precise recurrent risk in a subsequent pregnancy thereby facilitating genetic counseling and deciding further reproductive options.

Association of recurrent pregnancy loss with chromosomal abnormalities and hereditary thrombophilias

BACKGROUND

Recurrent pregnancy loss (RPL) which is generally known as >3 consecutive pregnancy losses before 20 weeks' gestation is seen in 0.5-2% of women.

OBJECTIVE

To evaluate the association of parental and fetal chromosomal abnormalities with recurrent pregnancy loss in our area and to analyze the frequency of three types of hereditary thrombophilia's; (MTHFR C677T polymorphisms, FV Leiden G1691A mutation and Prothrombin (factor II) G20210A mutation) in these female patients.

METHODS

The present case-control retrospective study was performed between February 2007 and December 2011 on 495 couples, who had two or more consecutive pregnancy losses before 20 weeks' gestation. We used conventional cytogenetic analysis and polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

Parental chromosomal abnormality was detected in 28 cases (2.8% of all cases, 5.7% of the couples) most of which (92.9%) were structural abnormalities. All of the structural abnormalities were balanced chromosomal translocations. Chromosomal analysis performed from the abortion materials detected a major chromosomal abnormality in 31.9% of the cases. The most frequently observed alteration in the hereditary thrombophilia genes was heterozygote mutation for the MTHFR C677T polymorphisms (n=55).

CONCLUSION

Balanced translocations are the most commonly detected chromosomal abnormalities in couples being evaluated for recurrent pregnancy loss and these patients are the best candidates for offering prenatal genetic diagnosis by the help of which there is a possibility of obtaining a better reproductive outcome.

Chromosomal abnormalities as a cause of recurrent abortions in Egypt

BACKGROUND:

In 4%-8% of couples with recurrent abortion, at least one of the partners has chromosomal abnormality. Most spontaneous miscarriages which happen in the first and second trimesters are caused by chromosomal abnormalities. These chromosomal abnormalities may be either numerical or structural.

MATERIAL AND METHODS:

Cytogenetic study was done for 73 Egyptian couples who presented with recurrent abortion at Genetic Unit of Children Hospital, Mansoura University.

RESULTS:

We found that the frequency of chromosomal abnormalities was not significantly different from that reported worldwide. Chromosomal abnormalities were detected in 9 (6.1%) of 73 couples. Seven of chromosomal abnormalities were structural and two of them were numerical.

CONCLUSION:

Our results showed that 6.1% of the couples with recurrent abortion had chromosomal abnormalities, with no other abnormalities. We suggest that it is necessary to perform cytogenetic in vestigation for couples who have recurrent abortion.

A cytogenetic study of couples with repeated spontaneous abortions

BACKGROUND AND OBJECTIVE

The frequency of chromosomal aberrations in Iran is not definitely known. This study determined the frequency of chromosomal aberrations in a series of couples with two or more spontaneous abortions and compared the findings with that reported from other countries.

METHODS

This was a descriptive study conducted on 100 couples with recurrent abortions. Both partners were karyotyped as part of the primary investigation. Other probable causes of abortion were also investigated.

RESULTS

Chromosomal aberrations were found in 8 (8%) of the females and 5 (5%) of the males. The prevalence of chromosomal abnormalities was as follows: 4 (30.8%) balanced reciprocal translocations, 3 (23%) Robertsonian translocations, 3 (23%) pericentric inversions, 1 (7.7%) paracentric inversion, 1 (7.7%) chromosomal marker, and 1 (7.7%) polymorphism 9qh+.

CONCLUSIONS

The pattern of chromosomal aberrations was similar to that reported in other studies, but the prevalence of chromosomal aberrations was higher.

Cytogenetic abnormalities in 1162 couples with recurrent miscarriages in southern region of India: report and review

PURPOSE

The purpose of the present study was to investigate the contribution of chromosomal anomalies and the frequency of a particular type of aberration in couples with recurrent miscarriages.

METHODS

A total of 1,162 couples with recurrent miscarriages were analyzed using G-banding and Fluorescence in situ hybridization where ever necessary.

RESULTS

Chromosomal anomalies were detected in 78 cases. This study describes majority of the cases with balanced reciprocal translocations. Among the abnormal karyotypes we also report for the first time three unique translocations involving (3;14), (18;22) and (X;22) chromosomes which were confirmed by molecular cytogenetic methods.

CONCLUSIONS

The review of literature and the overall incidence of the abnormalities suggest that chromosomal analysis in couples with recurrent miscarriages should be taken up by all the practioners at all levels. This not only helps to check the cytological abnormalities but also helps to correlate the recurrent abnormalities in a given population. Thus establishing and correlating the environmental and genetic condition of that particular phenotype and genotype.