Outcome of preimplantation genetic diagnosis using FISH analysis for recurrent miscarriage in low-risk reciprocal translocation carriers

Chromosome 17 translocation affects sperm morphology: Two case studies and literature review

We present two cases of infertile males with teratozoospermia stemming from chromosome 17 translocation. The patients present karyotypes that have not been previously reported. Genes located on breakpoints (17p11.2, 9q31, and 11p15) were analysed to find the probable mechanism affecting sperm morphology. Our results suggest that ALKBH5, TOP3A, and LLGL1 interactions may be an underlying cause of abnormal sperm head morphology. Translocation of chromosome 17 occurred in conjunction with chromosome 9 and chromosome 11 translocation in the two cases, resulting in oligozoospermia and asthenozoospermia, respectively. These abnormal phenotypes may involve meiosis- and motility-related genes such as LDHC, DNHD1, UBQLN3, and NUP98. Translocation is thus a risk factor for sperm morphological abnormalities and motility deficiency. The interaction network of 22 genes on breakpoints suggests that they contribute to spermatogenesis as a group. In conclusion, this study highlighted the importance of investigating genes linked to sperm morphology, together with chromosome 17 translocation and reproductive risks. For patients interested in screening before a future pregnancy, we recommend preimplantation genetic diagnosis to reduce the risk of karyotypically unbalanced foetuses and birth defects.

Analysis of 2 men with t(8;22)(q13;q13) and t(8;14)(q13;q22) chromosomal translocation karyotypes

Male infertility is a multifactorial condition that is closely associated with chromosomal abnormalities. Reciprocal chromosomal translocation (RCT) is a significant structural genetic abnormality. The specific mechanisms of forms of RCT affecting male infertility include the product of chromosomally unbalanced gametes, thereby disrupting the structure and function of important genes responsible for spermatogenesis. RCT breakpoints have been found to disrupt gene structure and function in many medical fields However, the relationship between RCT breakpoints and male infertility remains to be determined. The purpose of this study is to describe 2 male carriers of RCTs 46,XY,t(8;22)(q13;q13) and 46,XY,t(8;14)(q13;q22). Both patients were collected from the second hospital of Jilin University. Semen parameters were detected using the computer-aided semen analysis system. Cytogenetic analysis was performed using standard operating procedure. Related genes on chromosomal breakpoints were searched using Online Mendelian Inheritance in Man. One man had semen parameters within the normal range, but the couple was infertile after 5 years of marriage. The other man showed normal semen parameters, and his wife had experienced 2 spontaneous miscarriages. Using a literature search, the association between chromosome 22q13 breakpoint and fertility were investigated. The results suggest that physicians should focus on the clinical phenotype of the patients and the breakpoints of RCT in genetic counseling. An important gene related to human male infertility is clearly located in chromosome region 22q13, and its function is worthy of further study.

The Clinical Effectiveness of Preimplantation Genetic Diagnosis for Chromosomal Translocation Carriers: A Meta-analysis

Published data on the relationship between pregnancy outcomes of preimplantation genetic diagnosis (PGD) in translocation carriers have implicated inconclusive results. To identify potentially eligible reports, an electronic search was conducted in several databases, including PubMed, Scopus, Web of Knowledge, and Cochrane. Pooled odd ratios (ORs) and 95% confidence intervals (Cis) were estimated based on a random-effect model to evaluate the strength of association between PGD and successful pregnancy outcome in translocation carriers. A total of six cohort studies were included in the current study. The meta-analysis of these studies revealed that the PGD method was associated with an increased successful pregnancy outcome of translocation carriers (OR = 8.58; 95%CI: 1.40–52.76). In subgroup analysis, there was no significant association according to the chromosomal translocation carrier origin and the type of translocated chromosomes, as well as country. In developed countries, the pregnancy outcome of PGD was significantly improved in translocation carriers (OR = 21.79; 95%CI: 1.93–245.52). The current meta-analysis demonstrated that the PGD method is associated with successful pregnancy outcome in both types of reciprocal and Robertsonian translocation carriers, especially in developed countries.

Clinical Features of Infertile Men Carrying a Chromosome 9 Translocation

Previous studies indicated that chromosome 9 translocations are involved in reduced male fertility and increased chance of miscarriage in the female partner. The aim of this study was to review the clinical features and genetic counselling requirements of infertile men carrying chromosome 9 translocations. This study analyzed fertile-age male carriers of chromosome 9 translocations, and included 12 clinical cases in our hospital. In our cases, three cases had oligozoospermia or severe oligozoospermia, while nine cases had normal semen. Of the latter nine cases, seven were associated with recurrent spontaneous abortions, and two produced a phenotypically normal child as confirmed by amniocentesis. Male chromosome 9 translocations and specific breakpoints from reported papers were searched using PubMed and CNKI database. A literature review identified 76 male patients who carried chromosome 9 translocations. Breakpoints at 9p12, 9p11, 9p10 and 9q34.1 were related to pregestational infertility, while breakpoints at 9p21, 9q10, 9q11, 9q13, 9q21.1, 9q22, 9q22.2, 9q22.3, 9q34, 9q34.2 and 9q34.3 exhibited gestational infertility. Chromosome translocations involving chromosome 9 lead to increased risk of miscarriage. Carriers of chromosome 9 translocations should be counselled to consider in vitro fertilization accompanied by preimplantation genetic diagnosis.

Pregnancy outcomes of reciprocal translocation carriers with two or more unfavorable pregnancy histories: before and after preimplantation genetic testing

PURPOSE

To report the normal live birth and birth defect rates pre- and post- preimplantation genetic testing for chromosomal structural rearrangements (PGT-SR) in reciprocal translocation carriers who have experienced two or more unfavorable pregnancy histories.

METHODS

We conducted a retrospective cohort study of 194 couples who underwent 265 PGT-SR cycles between January 2013 and August 2016. The rates of miscarriage, normal live birth, and birth defect pre- and post- PGT-SR treatment were recorded. The types of birth defect were also categorized.

RESULTS

Before PGT-SR treatment, the 194 couples with reciprocal translocation had a previous reproductive history consisting of 592 pregnancies in total: 496 (83.8%) were miscarriages; 29 (4.9%) ended by induced abortion due to unintended pregnancy; 36 (6.1%) had birth defects; and 17 (2.9%) were normal live births. After PGT-SR treatment, there were 118 clinical pregnancies. Of these pregnancies, 13 (11.0%) were miscarriages, 101 (85.6%) were normal live births, and 4 (3.4%) had birth defects. In total, 14 different disorders were noted in the prenatal and postnatal examinations. Before the PGT-SR treatment, multiple birth defects, central nervous system abnormalities, and congenital heart defects were the three most common congenital malformations. Excluding for methylmalonic acidemia, there were only single and mild birth defects after the PGT-SR treatment.

CONCLUSIONS

After the PGT-SR treatment, the reciprocal translocation carriers who had previously experienced two or more unfavorable pregnancy outcomes had a low risk of miscarriages and birth defects. The rate of normal live births per pregnancy was higher after PGT-SR treatment.

Clinical feature of infertile men carrying balanced translocations involving chromosome 10: Case series and a review of the literature

RATIONALE

Infertile male carrying balanced translocations can be broadly divided into two types: pregestational and gestational infertility. Chromosome and breakpoints involved translocation should be considered in genetic counselling for these patients. To date, > 100 cases have been described with carrying balanced translocations involving chromosome 10 in fertile male.

PATIENT CONCERNS

We report 11 cases translocation carriers involving chromosome 10, and review 99 carriers of chromosome 10 translocation from reported literature.

DIAGNOSES

Eleven cases of chromosomal translocation were diagnosed by cytogenetic analysis. Three of these men had azoospermia or oligozoospermia, while eight had normal semen. Of these latter cases, their partners were able to conceive, but had a tendency to miscarry or have a stillbirth.

INTERVENTIONS

Chromosome breakpoints should be considered in genetic counseling. Preimplantation genetic diagnosis should be performed to decrease the high risk of miscarriage and to minimize the genetic risks to offspring for patients with gestational infertility.

OUTCOMES

The most common translocations and breakpoints were at t(4;10) and 10q24, observed in 12 and 10 patients respectively. Breakpoints at 10p15.1, 10p12, 10q10, 10q22.1, 10q24.2, and 10q26.3 were linked to pregestational infertility; breakpoints at 10p12.1, 10q11, 10q21.2, and 10q23.3 were associated with gestational infertility; the other breakpoints were connected with both forms of infertility.

LESSONS

Breakpoints at 10p12 and 10q26.3 were associated with pregestational infertility. Other breakpoints at chromosome 10 were correlated with gestational infertility. These breakpoints should be considered when counseling men with chromosome 10 translocations should be informed of their options.

Does preimplantation genetic diagnosis improve reproductive outcome in couples with recurrent pregnancy loss owing to structural chromosomal rearrangement? A systematic review

Recurrent pregnancy loss (RPL) is a common, yet elusive, complication of pregnancy. Among couples at high risk of RPL, such as those carrying a structural chromosomal rearrangement, preimplantation genetic diagnosis (PGD) has been proposed as a tool to improve live birth rates and reduce the incidence of miscarriage; however, no clear consensus has been reached on its benefits in this population. This systematic review summarizes existing published research on the effect of PGD on pregnancy outcomes among carriers of chromosomal abnormalities with RPL. A comprehensive search of common databases was conducted, which yielded 20 studies. Meta-analysis was precluded owing to significant heterogeneity between studies. The primary outcome of interest was live birth rate (LBR), and a pooled total of 847 couples who conceived naturally had a LBR ranging from 25-71% compared with 26.7-87% among 562 couples who underwent IVF and PGD. Limitations of the study include lack of large comparative or randomized control studies. Patients experiencing RPL with structural chromosomal rearrangement should be counselled that good reproductive outcomes can be achieved through natural conception, and that IVF-PGD should not be offered first-line, given the unproven benefits, additional cost and potential complications associated with assisted reproductive technology.

A report of nine cases and review of the literature of infertile men carrying balanced translocations involving chromosome 5

Background

Balanced translocations may cause the loss of genetic material at the breakpoints and may result in failure of spermatogenesis. However, carriers of reciprocal translocation may naturally conceive. Genetic counseling of male carriers of translocations remains challenging. This study explores the clinical features of carriers of chromosome 5 translocations, enabling informed genetic counseling of these patients.

Results

Of 82 translocation carriers, 9 (11%) were carriers of a chromosome 5 translocation. One case had azoospermia, while three cases had experienced recurrent spontaneous abortions, two cases had each experienced stillbirth, and three cases produced a phenotypically normal child confirmed by amniocentesis. A literature review identified 106 patients who carried chromosome 5 translocations. The most common chromosome 5 translocation was t(4,5), observed in 13 patients. Breakpoint at 5p15 was observed in 11 patients. All breakpoints at chromosome 5 were associated with gestational infertility.

Conclusion

In genetic counseling, physicians should consider chromosome 5 and its breakpoints. Carriers of chromosome 5 translocations may continue with natural conception or use assisted reproductive technologies, such as preimplantation genetic diagnosis.

Prevalence and Treatment Choices for Couples with Recurrent Pregnancy Loss Due to Structural Chromosomal Anomalies

OBJECTIVE

Parental carriers of balanced structural chromosomal rearrangements such as reciprocal or Robertsonian translocations are at increased risk of recurrent pregnancy loss (RPL) due to the production of gametes with unbalanced non-viable chromosome variants. As a purported means of improving reproductive outcomes in this population, IVF and preimplantation genetic diagnosis (PGD) have been introduced as an alternative to natural conception and prenatal diagnosis. In this study, we evaluate the prevalence and treatment choices of couples with structural chromosomal rearrangement referred to a tertiary care RPL clinic. In addition, we compare the two methods of management in terms of live birth rate.

METHODS

This is a retrospective chart review of 2321 couples who were referred to a highly specialized RPL clinic for ongoing clinical management between January 2005 and December 2013 (n = 23). Couples who pursued PGD through local fertility centres during this time were also included (n = 13).

RESULTS

Thirty-six couples (1.6%) were found to be parental carriers of a structural chromosomal rearrangement. In this cohort, couples were twice as likely to pursue natural conception compared with IVF with PGD. No significant differences were observed in live birth rate between PGD and clinical management (66.6% vs. 53.3%, P = 0.717). With PGD management, six live birth outcomes were observed, with an incidence of one birth in 5.63 years of follow-up. With clinical management, 24 live birth outcomes were observed, with an incidence of one birth in 4.09 years of follow-up. Mean time to live birth was 17.5 months and 23.3 months in clinical management and PGD, respectively.

CONCLUSIONS

Among couples presenting to a tertiary RPL clinic, parental carriers of structural chromosomal rearrangement and history of RPL are more likely to pursue natural conception over IVF and PGD. With regards to reproductive outcomes, no significant difference in miscarriage rate, time to live birth, or live birth rate was observed between couples who pursued PGD compared with expectant clinical management.