Reproductive outcomes in recurrent pregnancy loss associated with a parental carrier of chromosome abnormalities or polymorphisms

Fertility problems in men carrying chromosome 7 inversion: A retrospective, observational study

Infertility is a worldwide public health issue. Fifty percent of infertile couples are male-only. A number of male infertility etiologies are significantly influenced by chromosomal abnormalities. Clinical manifestations, however, differ according to the presence of aberrant chromosomes and distinct breakpoints. The reproductive effects of inversion are evident in those who carry it. The influence of inverted carriers on male infertility may be explained by the interchromosomal effect, although further research is still needed to determine the precise mechanism. Furthermore, selecting clinical reproductive technology presents difficulties for both physician and patients. The aim of this study is to determine the clinical characteristics of 4 males who have an inversion of chromosome 7, and to investigate the connection between the breakpoints of this chromosome and male infertility. For each patient, cytogenetic and semen analyses were carried out. Using PubMed or Online Mendelian Inheritance in Man, relevant research and genes on breakpoints on chromosome 7 were found. This study includes 4 male infertile patients, all of whom had chromosome 7 inversions. 46,XY,inv(7)(p22q22), 46,XY,inv(7)(p21q11.2), 46,XY,inv(7)(p21q21), and 46,XY,inv(7)(p15q36) were the results of the cytogenetic analysis. Three cases of aberrant semen parameters were detected by semen detection. After a literature search, 21 cases of chromosome 7 inversion carriers were found. These carrier couples have varying reproductive histories. Among the 5 cases where semen parameters are available, 1 is azoospermia and 1 is oligoasthenozoospermia. Five significant genes on chromosome 7 have been linked to male infertility. Changes in semen parameters may be connected to the breakpoints 7q11, 7q21, 7q22, and 7q36. Physicians should take into account the relevant breakpoints when offering genetic counseling to patients who have chromosome 7 inversion.

Systematic review of subsequent pregnancy outcomes in couples with parental abnormal chromosomal karyotypes and recurrent pregnancy loss

OBJECTIVE

To evaluate the current evidence of pregnancy outcomes among couples with recurrent pregnancy loss (RPL) with abnormal karyotypes vs. those with normal karyotypes and among couples with RPL and abnormal karyotypes after receiving expectant management vs. preimplantation genetic diagnosis (PGD).

DESIGN

Systematic review and meta-analysis.

SETTING

Academic medical centers.

PATIENT(S)

Pregnancy outcomes in 6,301 couples with RPL who conceived without medical intervention in 11 studies were analyzed. However, only 2 studies addressed the outcomes of couples with RPL and abnormal karyotypes after expectant management (75 cases) vs. PGD (50 cases).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The pregnancy outcomes in couples with RPL with abnormal and normal karyotypes across included studies were evaluated.

RESULT(S)

Compared with those with a normal karyotype, a significantly lower first pregnancy live birth rate (LBR) was found in couples with RPL with abnormal karyotypes (58.5% vs. 71.9%; odds ratio [OR], 0.55; 95% confidence interval [CI], 0.46-0.65; I² =27%). A markedly decreased first pregnancy LBR was found in couples with a translocation (52.9% vs. 72.4%; OR, 0.44; 95% CI, 0.31-0.61; I² =33%) but not in couples with an inversion. However, the differences in accumulated LBR (81.4% vs. 74.8%; OR, 0.96; 95% CI, 0.90-1.03; I² = 0) were nonsignificant, whereas the miscarriage rate was distinctly higher in couples with RPL and abnormal karyotypes (53.0% vs. 34.7%; OR, 2.21; 95% CI, 1.69-2.89; I² = 0). Compared with those who chose expectant management, differences in accumulated LBR were nonsignificant (60% vs. 68%; OR, 0.55; 95% CI, 0.11-2.62; I² =71%), whereas the miscarriage rate (24% vs. 65.3%; OR, 0.15; 95% CI, 0.04-0.51; I² = 45) was markedly low in couples with RPL and abnormal karyotypes who chose PGD.

CONCLUSION(S)

Couples with RPL and abnormal karyotypes had a higher miscarriage rate than couples with normal karyotypes but achieved a noninferior accumulated LBR through multiple conception attempts. In couples with RPL and abnormal karyotypes, PGD treatment did not increase the accumulated LBR but markedly reduced miscarriage rate compared with expectant management.

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.

Study of Spectrum of Chromosomal Rearrangements in Recurrent Pregnancy Loss

Introduction

Recurrent pregnancy losses (RPLs) are seen in up to 15-20% of all clinically recognized pregnancies, 1-2% of women in general population. Repeated losses are seen in 5-10% of women. The prevalence of chromosomal rearrangements is 6.65% in couples with repeated pregnancy losses. Two to 4% of RPL are associated with parental balanced reciprocal and Robertsonian translocations.

Materials and Methods

The study was conducted at a tertiary care hospital in New Delhi, and in total, 204 couples with RPL enrolled in the study.

Results

In total, 4490 couples presented to the obstetric clinic, of which 204 (4.5%) couples had repeated pregnancy losses. Cytogenetic analysis was done in 198 couples. Out of total 198 patients, 14 patients (7.1%) had cytogenetic alterations. Most common aberrations observed were structural rearrangements, of which reciprocal translocations were more common. In our study cohort, all the couples had maternal age of ≤ 35 years and all the alterations were seen either in mother or in both parents.

Discussion

Our study highlights that cytogenetic alterations not only are common in first trimester miscarriages, but are an important event in miscarriages presenting at later period of gestation and in young mothers as well.

Clinical features of carriers of reciprocal chromosomal translocations involving chromosome 2: report of nine cases and review of the literature

OBJECTIVE

To explore the clinical features of carriers of chromosome 2 translocations, enabling informed genetic counseling of these patients.

MATERIALS AND METHODS

Eighty-two male carriers of a translocation who were infertile or receiving fertility counseling were recruited. Cytogenetic analyses were performed using G-banding. A search of PubMed was performed to determine whether the identified translocations on chromosome 2 are involved in male infertility. The relationships of translocation breakpoints with male infertility and recurrent pregnancy loss were analyzed.

RESULTS

Of the 82 translocation carriers, 9 (11%) were carriers of a chromosome 2 translocation. Four cases had oligozoospermia or infertility, while five had normal semen. In an analysis of the literature, 55 patients who were carriers of chromosome 2 translocations were also reviewed. Breakpoints at 2p13 and 2q31 were observed in six patients each, and were the most common. Breakpoints at 2p23, 2p13, 2p11.2, 2q31, and 2q37 were associated to both pre-gestational and gestational infertility, while other breakpoints were associated with gestational infertility.

CONCLUSIONS

All breakpoints at chromosome 2 were correlated with gestational infertility. Carriers of chromosome 2 translocations should therefore receive counseling to continue with natural conception and use of different technologies available via assisted reproductive technology, such as preimplantation genetic diagnosis.

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.

Male chromosomal polymorphisms reduce cumulative live birth rate for IVF couples

PURPOSE

Chromosomal polymorphisms are associated with infertility, but their effects on assisted reproductive outcomes are still quite conflicting, especially after IVF treatment. This study evaluated the role of chromosomal polymorphisms of different genders in IVF pregnancy outcomes.

METHODS

Four hundred and twenty-five infertile couples undergoing IVF treatment were divided into three groups: 214 couples with normal chromosomes (group A, control group), 86 couples with female polymorphisms (group B), and 125 couples with male polymorphisms (group C). The pregnancy outcomes after the first and cumulative transfer cycles were analyzed, and the main outcome measures were live birth rate (LBR) after the first transfer cycle and cumulative LBR after a complete IVF cycle.

RESULTS

Comparison of pregnancy outcomes after the first transfer cycle within group A, group B, and group C demonstrated a similar LBR as well as other rates of implantation, clinical pregnancy, early miscarriage, and ongoing pregnancy (P > 0.05). However, the analysis of cumulative pregnancy outcomes indicated that compared with group A, group C had a significantly lower LBR per cycle (80.4 vs 68.00%), for a rate ratio of 1.182 (95% CI 1.030 to 1.356, P = 0.01) and a significantly higher cumulative early miscarriage rate (EMR) among clinical pregnancies (7.2 vs 14.7%), for a rate ratio of 0.489 (95% CI 0.248 to 0.963, P = 0.035).

CONCLUSION

Couples with chromosomal polymorphisms in only male partners have poor pregnancy outcomes after IVF treatment manifesting as high cumulative EMR and low LBR after a complete cycle.