Karyotype analysis in large-sample infertile couples living in Central China: a study of 14965 couples

Genetic anomalies in infertile Egyptian men and their impact on sperm retrieval rates and intracytoplasmic sperm injection outcome: A retrospective cohort study

BACKGROUND AND OBJECTIVES

The current retrospective study aimed to investigate the frequency and types of chromosomal abnormalities among a group of infertile men, as well as their impact on semen parameters, sperm retrieval rates (SRR), and intracytoplasmic sperm injection (ICSI) outcomes.

MATERIALS AND METHODS

Two thousand five hundred sixty-one Egyptian men were retrospectively evaluated between 2015 and 2020. Patients underwent infertility assessment, including semen analysis, hormonal evaluation, karyotyping, and, when applicable, Y chromosome microdeletion analysis. ICSI was conductedon a total of 1541 individuals.

RESULTS

Our cohort included 1188 men with azoospermia (46.4%), and 457 having sperm concentrations less than 2 million/mL (17.8%). A normal male karyotype (46, XY) was observed in 2227 men (87%). We detected Klinefelter syndrome (KF) in 224 men (8.7%). Other chromosomal abnormalities, excluding KF, were identified in 110 men (4.3%), classified as compatible (N = 89) or incompatible (N = 21) with ICSI. The SRR for men with normal karyotypes was 48.6% (336/692), compared to 26.0% (19/73) for men with KF (P = 0.0003). Men with anomalies other than KF had a higher SRR of 55.6% (15/27) than those with KF (P = 0.0086). Clinical pregnancy rates were 44.1% for normal karyotypes, 33.3% for KF, and 32.3% for compatible chromosomal abnormalities (p > 0.05).The blastulation rate for men with compatible chromosomal abnormalities was 11.9%, while it was 27% for KF (p = 0.0001). Fertilization (FR) and implantation rates (IR) for KF were comparable to those with compatible abnormalities (FR: 65 .6% vs. 70.7%; IR: 18 .8% vs. 19.3%, P = 0.477, P = 0.530). The total testosterone (TT) level did not discriminate or predict testicular sperm extraction (TESE) outcome in men with KF and in men with other anomalies.

DISCUSSION & CONCLUSION

The incidence of chromosomal abnormalities as a cause of severe male infertility in this study is within the similar range reported internationally and in the Mediterranean region. The impairment of spermatogenesis is reflected by the lower SRR in KF patients. Spermatozoa retrieved from men with KF are expected to yield the same FR, blastulation rate (BR), and IR as those collected from men with a normal set of chromosomes. However, the negative prognostic effects of other chromosomal abnormalities on ICSI outcomes, especially low BR, should be clearly explained to these patients during counseling for assisted reproductive techniques.

Oocyte/zygote/embryo maturation arrest: a clinical study expanding the phenotype of NOBOX variants

PURPOSE

Primary ovarian insufficiency (POI) is an important cause of female infertility, stemming from follicle dysfunction or premature oocyte depletion. Pathogenic variants in genes such as NOBOX, GDF9, BMP15, and FSHR have been linked to POI. NOBOX, a transcription factor expressed in oocytes and granulosa cells, plays a pivotal role in folliculogenesis. Loss-of-function variants in NOBOX are reported in 1-2% of POI women. This study aims to describe the association of novel NOBOX variants with a distinct oocyte, zygote, and embryo maturation arrest (OZEMA) phenotype in infertile women.

METHODS

Three unrelated women experiencing OZEMA and undergoing multiple in vitro fertilization (IVF) cycles present with a germline NOBOX variant. The detected variants were cross-referenced with a large genetic database to explore their association with IVF outcomes.

RESULTS

A heterozygous NM_001080413.3 (NOBOX): c.1797_1798del, p.(Cys600Phefs*27) variant was detected in a woman with oocyte maturation arrest. Another heterozygous variant, NM_001080413.3 (NOBOX): c.1849C > T, p.(His617Tyr), was detected in two women experiencing embryonic developmental arrest. Segregation analysis in one of the two latter families revealed the presence of the p.(His617Tyr) variant in an affected sister, while the two fertile sisters did not carry this variant. Furthermore, the p.(His617Tyr) variant was found in three women in a large database of whom two presented with an embryonic developmental arrest.

CONCLUSION

Two heterozygous NOBOX variants were identified in women with an OZEMA phenotype. Where pathogenic NOBOX variants are typically linked to POI, our clinical findings suggest that NOBOX plays a role in subsequent oocyte maturation and early embryo development.

Characteristics and clinical evaluation of X chromosome translocations

BACKGROUND

Individuals with X chromosomal translocations, variable phenotypes, and a high risk of live birth defects are of interest for scientific study. These characteristics are related to differential breakpoints and various types of chromosomal abnormalities. To investigate the effects of X chromosome translocation on clinical phenotype, a retrospective analysis of clinical data for patients with X chromosome translocation was conducted. Karyotype analysis plus endocrine evaluation was utilized for all the patients. Additional semen analysis and Y chromosome microdeletions were assessed in male patients.

RESULTS

X chromosome translocations were detected in ten cases, including seven females and three males. Infantile uterus and no ovaries were detected in case 1 (FSH: 114 IU/L, LH: 30.90 mIU/mL, E2: < 5.00 pg/ml), and the karyotype was confirmed as 46,X,t(X;22)(q25;q11.2) in case 1. Infantile uterus and small ovaries were both visible in two cases (FSH: 34.80 IU/L, LH: 17.06 mIU/mL, E2: 15.37 pg/ml in case 2; FISH: 6.60 IU/L, LH: 1.69 mIU/mL, E2: 23.70 pg/ml in case 3). The karyotype was detected as 46,X,t(X;8)(q13;q11.2) in case 2 and 46,X,der(X)t(X;5)(q21;q31) in case 3. Normal reproductive hormone levels and fertility abilities were found for cases 4, 6 and 7. The karyotype were detected as 46,X,t(X;5)(p22.3;q22) in case 4 and 46,X,der(X)t(X;Y)(p22.3;q11.2) in cases 6 and 7. These patients exhibited unremarkable clinical manifestations but experienced a history of abnormal chromosomal pregnancy. Normal phenotype and a complex reciprocal translocation as 46,X,t(X;14;4)(q24;q22;q33) were observed in case 5 with a history of spontaneous abortions. In the three male patients, multiple semen analyses confirmed the absence of sperm. Y chromosome microdeletion and hormonal analyses were normal. The karyotypes were detected as 46,Y,t(X;8)(q26;q22), 46,Y,t(X;1)(q26;q23), 46,Y,t(X;3)(q26;p24), respectively.

CONCLUSIONS

Our study provides insights into individuals with X chromosome translocations. The clinical phenotypes are variable and unpredictable due to differences in breakpoints and X chromosome inactivation (XCI) patterns. Our results suggest that physicians should focus on the characteristics of the X chromosome translocations and provide personalized clinical evaluations in genetic counselling.

Detection of chromosome aberrations in 17 054 individuals with fertility problems and their subsequent assisted reproductive technology treatments in Central China

STUDY QUESTION

How do the types and frequency of chromosome aberrations in couples in central China affect fertility and ART treatment?

SUMMARY ANSWER

Men with chromosome aberrations or polymorphisms have an increased risk of semen quality impairment and infertility, and couples affected by reciprocal translocations had a lower pregnancy rate compared with other chromosome aberrations.

WHAT IS KNOWN ALREADY

Karyotyping is crucial for patients affected by infertility as chromosome aberrations play an important role in the etiology of male infertility. However, the influence of chromosome aberrations and polymorphisms on sperm motility and morphology remains controversial. Data on ART treatment outcomes in infertile couples affected by chromosome aberrations are insufficient.

STUDY DESIGN, SIZE, DURATION

We conducted a retrospective study involving 17 054 patients affected by infertility who underwent karyotyping in our center between January 2020 and May 2022.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Karyotyping was performed on 17 054 patients with reproductive failure. All patients were from the central regions of China. The following data were collected from a medical records system using patient identification numbers: couples' ages, history of pregnancy and childbirth, type of infertility, years of infertility, cause of infertility, chromosome karyotypes, semen analysis results, assisted reproductive techniques performed, and treatment outcomes of ART.

MAIN RESULTS AND THE ROLE OF CHANCE

The incidence of chromosome aberrations was 2.04%; 2.49% in men and 1.57% in women. By analyzing the relationships between chromosome aberrations/polymorphisms and abnormal semen parameters, we found that there were significantly higher rates of asthenozoospermia, oligospermia, and teratozoospermia among men with Robertsonian translocations and sex chromosomal structural aberrations compared with those with normal karyotypes. Higher rates of asthenozoospermia and teratozoospermia were also observed among men with autosomal reciprocal translocations. The incidence of chromosome aberrations in azoospermic men (13.75%), and in men with cryptozoospermia or severe oligospermia (6.97%) was significantly higher than that in men with mild oligospermia or normospermia (0.88-2.12%). In addition, we found that the progressive movement of sperm is impaired in men with Chromosome 21 polymorphisms compared with men with normal karyotypes (39.46% ± 20.51% vs 48.61% ± 18.76%, P = 0.026). The percentage of morphologically normal forms was lower in the chromosomal polymorphism group than in the normal karyotype group (5.01% ± 2.41% vs 5.59% ± 2.14%, P = 0.001), especially in men with polymorphisms on Chromosome 9 (enlarged Chromosome 9 heterochromatin [9qh+]: 4.48% ± 2.22% vs 5.59% ± 2.14%, P = 0.006; pericentric inversion of Chromosome 9 [inv(9)]: 5.09% ± 3.11% vs 5.59% ± 2.14%, P = 0.008). ART treatment was successful in 36.00% of couples affected by chromosome aberrations. However, couples affected by reciprocal translocations achieved a lower pregnancy rate (24.07%), which may be due to the lower euploidy rates (27.31%) when compared with that in other chromosome aberrations.

LIMITATIONS, REASONS FOR CAUTION

First, although the initial cohort was large, chromosome aberrations were identified in a small number of patients. Second, the observational nature of the study design is limiting. Third, the couples affected by infertility in this study were all outpatients that did not undergo identical comprehensive examinations except for karyotyping, leading to the incomplete collection of medical records. Also, the population included in this study mainly focused on couples affected by infertility, which may not be included in the European Association of Urology (EAU) recommendation on male infertility.

WIDER IMPLICATIONS OF THE FINDINGS

Men with chromosome aberrations or polymorphisms have an increased risk of semen quality impairment and infertility. Constitutional chromosome analysis is recommended for men affected by infertility and severe oligospermia or azoospermia to facilitate early and appropriate guidance for the most suitable treatment. Carriers of chromosome aberrations can achieve acceptable pregnancy outcomes through IVF. However, couples affected by reciprocal translocations have lower pregnancy rates, and more treatment cycles are needed before a successful pregnancy. A possible explanation may be the fewer euploid embryos obtained.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by Grant 2021YFC2700603 from the National Key Research & Development Program of China. The authors declare no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Case report: Optical genome mapping revealed double rearrangements in a male undergoing preimplantation genetic testing

Chromosome rearrangement is one of the main causes of abortion. In individuals with double chromosomal rearrangements, the abortion rate and the risk of producing abnormal chromosomal embryos are increased. In our study, preimplantation genetic testing for structural rearrangement (PGT-SR) was performed for a couple because of recurrent abortion and the karyotype of the male was 45, XY der (14; 15)(q10; q10). The PGT-SR result of the embryo in this in vitro fertilization (IVF) cycle showed microduplication and microdeletion at the terminals of chromosomes 3 and 11, respectively. Therefore, we speculated whether the couple might have a cryptic reciprocal translocation which was not detected by karyotyping. Then, optical genome mapping (OGM) was performed for this couple, and cryptic balanced chromosomal rearrangements were detected in the male. The OGM data were consistent with our hypothesis according to previous PGT results. Subsequently, this result was verified by fluorescence in situ hybridization (FISH) in metaphase. In conclusion, the male’s karyotype was 45, XY, t(3; 11)(q28; p15.4), der(14; 15)(q10; q10). Compared with traditional karyotyping, chromosomal microarray, CNV-seq and FISH, OGM has significant advantages in detecting cryptic and balanced chromosomal rearrangements.

Self-reported effects of perceived social support on marital quality in balanced translocation patients and their spouses undergoing preimplantation genetic testing in China: actor-partner interdependence model

This study aimed to analyse the relationship between perceived social support and marital quality in balanced translocation patients and their spouses undergoing a preimplantation genetic testing (PGT) treatment cycle in China. The authors assessed the actor and partner effects of perceived social support on marital quality in patient-spouse dyads using a dyadic analysis approach. In total, 59 couples were assessed using self-report questionnaires for marital quality and perceived social support. There were significant differences in marital quality between patients and their spouses (p=.0025) based on the APIM (actor-partner interdependence model) analyses. The perceived social support of both patients (p=.0076) and spouses (p<.001) had a significant effect on individual marital quality for actor effects. Partner effects showed that patients' perceived social support had a significant effect on spouses' marital quality (p=.0156) and the spouses' perceived social support had a significant effect on patients' marital quality (p=.0084). The findings indicate that the level of perceived social support affected both his/her own marital quality and that of his/her spouse.Impact StatementWhat is already known on this subject? Infertility and reproductive treatments affect both partners, that is, the couple as a unit and have a negative impact on an individual's marital satisfaction and social relationships.What do the results of this study add? There are significant differences in marital quality between balanced translocation patients and their spouses. Perceived social support significantly correlated with marital quality in both the actor and partner effects.What are the implications of these findings for clinical practice and/or further research? Health professionals should provide couple-based interventions involving both patients and spouses throughout the PGT treatment to improve perceived social support, thereby improving their marital quality.

Impact of parental chromosomal polymorphisms on the incidence of congenital anomalies and perinatal complications in a cohort of newborns conceived after ICSI + PGT-A

BACKGROUND

To assess the association between chromosomal polymorphisms (CPM) with congenital anomalies and perinatal complications in a cohort of newborns from couples undergoing intracytoplasmic sperm injection (ICSI), trophectoderm biopsy, and preimplantation genetic testing for aneuploidy (PGT-A).

METHODS

A retrospective cohort of singletons conceived after ICSI, trophectoderm biopsy, and PGT-A cycles performed at IVIRMA clinics in Spain over 4 years was involved in the study. Newborns were classified according to the parental karyotype analysis: Group I: non-carriers, Group II: CPM carriers. Couples with chromosomal anomalies and instances when both partners were CPM carriers were excluded from the study. The groups were compared for several perinatal complications.

RESULTS

There was a significant decrease in the number of NB with complications in the carrier group compared to the non-carriers (19.7% vs 31.9%, p = 0.0406). There were no statistical differences among the two groups regarding congenital anomalies, preterm birth, alterations in birth length and weight, cranial perimeter, Apgar test score, or sex ratio (p > 0.05).

CONCLUSIONS

Chromosomal polymorphisms appear to have no adverse effects on congenital anomalies or perinatal complications on newborns from ICSI + PGT-A cycles.

Preimplantation Genetic Testing for Couples with Balanced Chromosomal Rearrangements

BACKGROUND

Chromosomal rearrangements play an important role in infertility. Carriers of chromosomal rearrangements have a lower chance of producing normal or balanced gametes due to abnormal segregation of chromosomes at meiosis, which leads to recurrent spontaneous abortions and infertility. Preimplantation genetic testing for structural chromosome rearrangements (PGT-SR) is offered to couples who have balanced chromosomal rearrangements in order to select embryos with a balanced karyotype prior to implantation, thereby increasing the chances of pregnancy. The purpose of the current study was to assess the outcomes of PGT-SR in patients carrying various balanced chromosomal rearrangements and to assess their clinical pregnancy outcome after in vitro fertilization (IVF).

METHODS

In this study, infertile couples with balanced chromosomal abnormalities undergoing PGT-SR were retrospectively analyzed at a single fertility center from January 2016 to December 2019.

RESULTS

PGT-SR was performed on 87 embryos from 22 couples in whom one partner carried a balanced translocation or an inversion. Fifty-seven (65.5%) of these embryos had unbalanced or sporadic aneuploidies, 30 (34.5%) embryos were normal or chromosomally balanced, which were then transferred in 18 couples. A higher rate of unbalanced translocations in comparison to sporadic aneuploidies was observed in couples with reciprocal translocation. The live birth rate per embryo transfer was found to be 66.6% (12/18).

CONCLUSION

PGT-SR is a useful tool in selecting normal or balanced embryos for transfer in IVF, which could lead to a pregnancy by reducing the chance of miscarriages due to chromosome aneuploidy in couples with balanced chromosomal rearrangements.

Identification of an SRY-negative 46,XX infertility male with a heterozygous deletion downstream of SOX3 gene

Background

A male individual with a karyotype of 46,XX is very rare. We explored the genetic aetiology of an infertility male with a kayrotype of 46,XX and SRY negative.

Methods

The peripheral blood sample was collected from the patient and subjected to a few genetic testing, including chromosomal karyotyping, azoospermia factor (AZF) deletion, short tandem repeat (STR) analysis for AMELX, AMELY and SRY, fluorescence in situ hybridization (FISH) with specific probes for CSP 18/CSP X/CSP Y/SRY, chromosomal microarray analysis (CMA) for genomic copy number variations(CNVs), whole-genome analysis(WGA) for genomic SNV&InDel mutation, and X chromosome inactivation (XCI) analysis.

Results

The patient had a karyotype of 46,XX. AZF analysis showed that he missed the AZF region (including a, b and c) and SRY gene. STR assay revealed he possessed the AMELX in the X chromosome, but he had no the AMELY and SRY in the Y chromosome. FISH analysis with CSP X/CSP Y/SRY showed only two X centromeric signals, but none Y chromosome and SRY. The above results of the karyotype, FISH and STR analysis did not suggest a Y chromosome chimerism existed in the patient's peripheral blood. The result of the CMA indicated a heterozygous deletion with an approximate size of 867 kb in Xq27.1 (hg19: chrX: 138,612,879–139,480,163 bp), located at 104 kb downstream of SOX3 gene, including F9, CXorf66, MCF2 and ATP11C. WGA also displayed the above deletion fragment but did not present known pathogenic or likely pathogenic SNV&InDel mutation responsible for sex determination and development. XCI assay showed that he had about 75% of the X chromosome inactivated.

Conclusions

Although the pathogenicity of 46,XX male patients with SRY negative remains unclear, SOX3 expression of the acquired function may be associated with partial testis differentiation of these patients. Therefore, the CNVs analysis of the SOX3 gene and its regulatory region should be performed routinely for these patients.

Verification of a cryptic t(Y;15) translocation in a male with an apparent 45,X karyotype

Background

A rare disease is that an individual with a non-chimeric karyotype of 45,X develops into a male. We explored the genetic aetiology of an infertile male with an apparent 45,X karyotype, which was subsequently verified as cryptic translocation between chromosomes Y and 15.

Methods

DNA was extracted from the patient's peripheral blood. A range of genetic testing was performed, including conventional chromosomal karyotyping, short tandem repeat (STR) analysis for azoospermia factor (AZF) region, fluorescence in situ hybridization (FISH) with specific probes groups of DXZ1/DYZ3, DYZ3/D15Z1/PML and SRY/D15Z1/PML, and chromosomal microarray analysis (CMA) for genomic copy number variations (CNVs).

Results

The patient was found to have an apparent 45,X karyotype. STR analysis showed that he possessed a short arm of the Y chromosome, including the SRY gene; however, he was missing the long arm of the Y chromosome, including AZFa + b + c and Yqter. A FISH assay of DXZ1 and DYZ3 probes showed a green signal of the X centromere and a red of the Y centromeric signal on a D-group-sized chromosome. By FISH assaying with D15Z1 and DYZ3 probes, chromosomes 15 and Y centromeric signals appeared closely on a single chromosome, as the PML control probe ascertained. A further FISH assay with D15Z1 and SRY probes revealed a signal of the SRY gene at the end of one arm of chromosome 15. The result of the CMA indicated a deletion with an approximate size of 45.31 Mb spanning from Yq11 to Yter.

Conclusion

Our study enriched the karyotype-phenotype correlation of Y and 15 chromosomes translocation. It strengthened the critical roles of molecular genetic techniques in identifying the chromosomal breakpoints and regions involved. Genetic aetiology can guide early intervention in childhood and assisted reproduction in adulthood.

A novel SRY pathogenic variant from a 46,XY female harboring a nonsense point mutation (G to A) in position 293

46,XY female is a genetic disorder characterized by gonad gender not consistent with chromosomal sex. The SRY gene mutation is a common cause of 46,XY reversal type 1 (OMIM: 400044). Peripheral blood was collected from a 46,XY female patient and her father. Sex chromosomes were confirmed by karyotype analysis and fluorescence in situ hybridization (FISH) detection of the specific probe of sex chromosomes with cultured lymphocytes. After extracting blood genomic DNA, SRY characteristic fluorescence peak was detected by quantitative fluorescence PCR (QF-PCR) method. Whole exome was sequenced with NGS, and SRY gene was sequenced by Sanger sequencing, respectively. The chromosomes X and Y of the patient were confirmed by karyotype of 46,XY, and FISH specific probe of chromosome X and Y. SRY specific fluorescence peak was observed by QF-PCR. The whole-exome sequencing results showed chrY: 2655352(GRCh37): c.293G>A hemizygote mutation, confirmed by Sanger sequencing. The de novo mutation resulted in the mRNA encoding the tryptophan codon of 98 (UGG) change into a termination codon (UAG) (P.Trp98ter), and the translation process was terminated prematurely. The discovery of this novel mutation in the SRY gene helps elucidate the molecular mechanism of 46,XY female sex reversal and enriches such patients' genetic mutation spectrum.

Six families with balanced chromosome translocation associated with reproductive risks in Hainan Province: Case reports and review of the literature

BACKGROUND

Balanced translocation refers to the process where breakage and reconnection of chromosomes occur at abnormal positions. As the genetic substance with balanced translocation in individuals does not change, which is usually characterized by normal phenotype and intelligence, the individuals seek medical service after many miscarriages, resulting in considerable mental and physical burdens of the family members. In the current era with rapid advances in detection technology, cytogenetic examination, as a definitive approach, still plays an essential role.

CASE SUMMARY

We report six cases with balanced chromosome translocation: Case 1: 46,XY,t(3;12)(q27;q24.1), infertility after 3 years of marriage; Case 2: 46,XX,t(4;16)(q31;q12), small uterus and irregular menstruation; Case 3: 46,XY,t(4;5)(q33;q13),9qh+, not pregnant after arrested fetal development; Case 4: 46,XX,t(11;17)(q13;p11.2), not pregnant after two times of spontaneous abortion; Case 5: 46,XX,t(10;13)(q24;q21.2), not pregnant after arrested fetal development for once; Case 6: 46,XX,t(1;4)(p36.1;q31.1), not pregnant after arrested fetal development for two times. The first four cases had chromosomal aberration karyotypes.

CONCLUSION

These results suggested that balanced chromosomal translocation carriers are associated with reproductive risks and a very high probability of abnormal pregnancy. The discovery of the first four reported chromosomal aberration karyotypes provides an important basis for studying the occurrence of genetic diseases.

Analysis of segregation patterns of quadrivalent structures and the effect on genome stability during meiosis in reciprocal translocation carriers

STUDY QUESTION

Do specific factors affect the segregation patterns of a quadrivalent structure and can the quadrivalent affect genome stability during meiosis?

SUMMARY ANSWER

Meiotic segregation patterns can be affected by the carrier's gender and age, location of breakpoints and chromosome type, and the quadrivalent structure can increase genome instability during meiosis.

WHAT IS KNOWN ALREADY

Carriers of reciprocal translocations have an increased genetic reproductive risk owing to the complex segregation patterns of a quadrivalent structure. However, the results of previous studies on the factors that affect segregation patterns seem to be contradictory, and the effect of a quadrivalent on genome stability during meiosis is unknown.

STUDY DESIGN, SIZE, DURATION

We designed a retrospective study to analyze the segregation patterns of 24 chromosomes from reciprocal translocation and non-translocation patients. Data for 356 reciprocal translocation carriers and 53 patients with the risk to transmit monogenic inherited disorders (RTMIDs) undergoing PGD-single nucleotide polymorphism array analysis were collected. The study was performed between March 2014 and July 2017.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Segregation patterns of a quadrivalent in 1842 blastocysts from 466 assisted reproduction cycles of reciprocal translocation carriers were analyzed according to the location of chromosome breakpoints, the carrier's gender and age, and chromosome type. In addition, to analyze the effect of quadrivalent structure on genome stability, segregation products of chromosomes which are not involved in the translocation from translocation carriers were compared with those of 23 pairs of chromosomes in 318 blastocysts from 72 assisted reproduction cycles of patients with RTMIDs.

MAIN RESULTS AND THE ROLE OF CHANCE

The percentage of adjacent-2 products with severe asymmetric quadrivalent was significantly higher than those with mild asymmetric quadrivalent (P = 0.020) while, in contrast, the incidence of 4:0/others was lower (P = 0.030). The frequencies of adjacent-1, adjacent-2 and 3:1 products differed between male and female carriers (P < 0.001, P = 0.015 and P = 0.001, respectively), and also for adjacent-1 and 4:0/others products in young versus older carriers (P = 0.04 and P = 0.002, respectively). In addition, adjacent-1 products of a quadrivalent with an acrocentric chromosome were significantly higher than those of a quadrivalent without an acrocentric chromosome (P = 0.001). Moreover, a quadrivalent could significantly increase the frequencies of abnormal chromosomes compared to patients with RTMIDs (P = 0.048, odds ratio (OR) = 1.43, 95% CI = 1.01-2.43), especially for the male carriers (P = 0.018, OR = 1.58, 95% CI = 1.08-2.25). In contrast, for older carriers, no difference was found in both aneuploidy and segmental anomalies compared to patients with RTMIDs.

LIMITATIONS, REASONS FOR CAUTION

The study contained appropriate controls, yet the analysis was limited by a small number of control patients and embryos.

WIDER IMPLICATIONS OF THE FINDINGS

Until now, there had been no definite report about the effect of quadrivalents on genome stability in reciprocal translocation carriers compared with control samples, and in the present study the large sample size ensured a detailed analysis of factors with a possible impact on segregation patterns. These data provide a better insight into the meiotic mechanisms involved in non-disjunction events in gametes from reciprocal translocation carriers. In addition, our results will help to provide each reciprocal translocation carrier couple undergoing PGD with more appropriate genetic counseling and a better understanding of the large numbers of abnormal embryos with chromosome aneuploidy.

STUDY FUNDING/COMPETING INTEREST(S)

The research was supported by the Research Funding of Shanghai Ji Ai Genetics & IVF Institute and the authors declare a lack of competing interests in this study.

Karyotype analysis in large sample cases from Shenyang Women's and Children's hospital: a study of 16,294 male infertility patients

To explore that it is necessary to routinely detect chromosomes in infertile patients, we investigated peripheral blood lymphocyte karyotype in 16,294 male infertile patients in the north-east of China and analysed the incidence and type of chromosomal anomaly and polymorphism. G-banding karyotype analysis of peripheral blood lymphocytes was performed in 16,294 cases. Semen analysis was performed three times in all the men. PCR and FISH confirmed the presence of the SRY gene. The rate of chromosomal anomaly in the 16,294 male infertile patients was 4.15% (677/16,294). The rates of chromosomal anomaly were 0.24% in normal semen group, 12.6% in light oligoasthenospermia group, 4.7% in moderate-to-severe oligoasthenospermia group and 9.59% in azoospermia group. There are two male infertile patients with 45,X chromosome karyotype. One X male patient had confirmed the presence of the SRY gene and FISH analysis demonstrated its location on the p arm of chromosome 13. The other X male patient had not found SRY gene in its whole-genome DNA. Meanwhile, sperm motility is slightly oligo-asthenozoospermic at the age of 35-39 and nearly azoospermic at the age of 40-45. As the rates of chromosomal anomaly are 0.24% and 12.6% even in normal semen group and light oligoasthenospermia group, the rates of chromosomal polymorphism are 5.36% and 25.51% in normal semen group and light oligoasthenospermia group, respectively; it is necessary to explore peripheral blood lymphocyte karyotype in all infertile couples. We mentioned that Y, 1, 2, 9 and 12 chromosomes were quite important about male infertility. These findings demonstrate that autosomal retention of SRY can be submicroscopic and emphasise the importance of PCR and FISH in the genetic workup of the monosomic X male. At the same time, it suggested that male infertility might be related to meiotic disturbances with spermatogenetic arrest in Y-autosome translocations, which could result in infertility by reduction of sperm production. Last but not least, ageing is one of the factors that could reduce sperm motility and quality.