Type and frequency of chromosome aberrations in 781 couples undergoing intracytoplasmic sperm injection

Cytogenetic Investigation of Infertile Patients in Hungary: A 10-Year Retrospective Study

Chromosome abnormalities play a crucial role in reproductive failure. The presence of numerical or structural aberrations may induce recurrent pregnancy loss or primary infertility. The main purpose of our study was to determine the types and frequency of chromosomal aberrations in infertile patients and to compare the frequency of structural aberrations to a control group. Karyotyping was performed in 1489 men and 780 women diagnosed with reproductive failure between 2010 and 2020. The control group included 869 male and 1160 female patients having cytogenetic evaluations for reasons other than infertility. Sex chromosomal aberrations were detected in 33/1489 (2.22%) infertile men and 3/780 (0.38%) infertile women. Structural abnormalities (e.g., translocation, inversion) were observed in 89/1489 (5.98%) infertile men and 58/780 (7.44%) infertile women. The control population showed structural chromosomal abnormalities in 27/869 (3.11%) men and 39/1160 (3.36%) women. There were significant differences in the prevalence of single-cell translocations between infertile individuals (males: 3.5%; females: 3.46%) and control patients (males: 0.46%; females: 0.7%). In summary, this is the first report of cytogenetic alterations in infertile patients in Hungary. The types of chromosomal abnormalities were comparable to previously published data. The prevalence of less-studied single-cell translocations was significantly higher in infertile patients than in the control population, supporting an earlier suggestion that these aberrations may be causally related to infertility.

The predictive factors of successful sperm retrieval for men with Y chromosome AZFc microdeletion

PURPOSE

To identify key predictors for successful sperm retrieval in men with AZFc microdeletion.

METHODS

Totally, 71 infertile men with confirmed AZFc microdeletion were studied. For each patient, the endocrine profile including serum follicle stimulating hormone (FSH), luteinizing hormone, total testosterone, prolactin, and estradiol was recorded, along with intratesticular testosterone levels (ITT), age, and testicular size. The factors were further analyzed to determine the key predictors for successful sperm retrieval.

RESULTS

Of the 71 men with AZFc microdeletion, 52 (73.2%) were classified as having non-obstructive azoospermia (NOA), 7 (9.9%) as having cryptozoospermia, and 12 (15.8%) as having severe oligoasthenoteratozoospermia. Of the 52 men with azoospermia, 47 received microdissection testicular sperm retrieval, and sperm retrieval was successful in 35 of those cases (74.5%). A significantly lower serum FSH (p = 0.03) was found in those patients from whom sperm could be successfully retrieved. The area under the receiving operating characteristic curve for FSH was determined to be 0.721. Using an FSH cutoff point of 12.95 mIU/mL, the model for predicting successful sperm retrieval was found to have 51.4% sensitivity, 83.3% specificity, 90.0% positive predictive value, and 37.0% negative predictive value. ITT levels were obtained from 7 NOA patients, the mean ITT and the mean ITT/serum testosterone ratio was 1932.8 ng/ml and 567.2 in 6 men with successful sperm retrieval, whereas, in a patient with fail sperm retrieval, the levels were 2370 ng/ml and 393.0.

CONCLUSION

Men exhibiting AZFc microdeletion with discernible spermatogenesis from whom sperm was successfully retrieved by mTESE generally presented with relatively lower FSH levels.

Fertility problems in males carrying an inversion of chromosome 10

Chromosomal inversion is closely related to male infertility. Inversion carriers may produce abnormal gametes, which may lead to partial duplication/deletion of the embryonic chromosome and result in spontaneous abortion, a fetus with multiple anomalies, or birth of a malformed child. Genetic counselling remains challenging for these carriers in clinical practice. We report two male carriers with inversion of chromosome 10 and review 26 reported cases. In the first case, 46,XX,inv(10)(p13q22) of the fetal chromosome was found in prenatal diagnosis; this was inherited from the paternal side with 46XY,inv(10)(p13q22). Another case was a male carrier with inv(10)(q21.2q22.1). There have been 25 (89.3%) cases of pericentric inversion and three (10.7%) cases of paracentric inversion involving chromosome 10. Of 28 cases, nine were associated with pregestational infertility of the couples, while the other 19 cases were associated with gestational infertility of the couples or normozoospermia. The breakpoints at 10p15, 10p11, 10q11, and 10q21 were associated with pregestational infertility of the couples. The breakpoints at 10p15, 10p14, 10p13, 10p12, 10p11, 10q11, 10q21, 10q22, 10q23, 10q24, 10q25, and 10q26 were related to gestational infertility of the couples or normozoospermia. Although there is a high risk of infertility or recurrent miscarriages, carriers with inversion of chromosome 10 might produce healthy offspring. Natural pregnancy can be used as a choice for inversion carriers with recurrent spontaneous abortion.

Low-level X Chromosome Mosaicism: A Common Finding in Women Undergoing IVF

BACKGROUND/AIM

To determine the incidence of X chromosome mosaicism in women undergoing in vitro fertilization (IVF) treatment and present preimplantation genetic testing for aneuploidy (PGT-A) outcome of this group.

PATIENTS AND METHODS

A total of 1,058 women undergoing IVF and 154 women with no fertility problems were enrolled in the study. Karyotyping from peripheral blood lymphocytes was performed by conventional cytogenetics. Twenty-nine women with X mosaicism underwent PGT-A by array-comparative genomic hybridization from embryos at the blastocyst stage.

RESULTS AND CONCLUSION

Out of 1,058 women undergoing IVF, 166 (15.7%) had an abnormal karyotype. The most common finding (14.6%) was X chromosome mosaicism. Its frequency was higher in women >35 years old and reached 46.1% in those >45 years of age. PGT-A results of 130 blastocysts tested showed that 29/117 (24.8%) were euploid; 17/29 (60%) were transferred and 10/17 (70%) were successfully implanted, indicating that PGT-A may be an option for women with low-level X chromosome mosaicism undergoing IVF in order to improve the likelihood of a successful pregnancy outcome.

Molecular cytogenetic characterization of small supernumerary marker 15 in infertile male: A case report

Small supernumerary marker chromosomes (sSMCs) are defined as structurally abnormal chromosomes that may be detected pre- or postnataly in patients with developmental and/or mental retardation or infertility. sSMC on chromosome 15 accounts for the highest proportion of all sSMCs and may be detected in subfertile individuals. The present study reports the case of a male patient with oligoasthenoteratozoospermia and an sSMC. The sSMC was identified and characterized according to G-banding analysis, chromosomal microarray analysis (CMA) and fluorescence in situ hybridization (FISH) analysis. Chromosomal karyotype analysis suggested that the patient presented with 47,XY,+mar. CMA was used to characterize the sSMC, which revealed a 0.44-Mb microduplication in 6q25.3q26. Subsequently, FISH using centromere-specific probes for chromosomes 13/21, 14/22 and 15 was applied to identify the origin of the sSMC, which was finally determined to be inverted duplicated(15)(q11.2). It was hypothesized that heterochromatin in the sSMC is responsible for the patient's fertility problem. The presence of heterochromatin may disrupt regular meiosis, thereby affecting normal spermatogenesis. Impaired spermatogenesis in infertile males with an sSMC derived from chromosome 15 was also reviewed by searching published literature and the sSMC database (http://ssmc-tl.com/sSMC.html). For patients with low sperm parameters and complete absence of spermatozoa in the ejaculate, including infertile males with an sSMC with spermatozoa, intracytoplasmic sperm injection is considered as an effective assisted reproductive technique. It may be concluded that molecular cytogenetic techniques are critical tools for delineating sSMCs in infertile males and may be beneficial in identifying sSMC carriers to ensure they receive clinical genetic counseling.

Where are we going with gene screening for male infertility?

Male infertility is a heterogenous disease process requiring the proper functioning and interaction of thousands of genes. Given the number of genes involved, it is thought that genetic causes contribute to most cases of infertility. Identifying these causes, however, is challenging. Infertility is associated with negative health outcomes, such as cancer, highlighting the need to further understand the genetic underpinnings of this condition. This paper describes the genetic and genomic tests currently available to identify the etiology of male infertility and then will discuss emerging technologies that may facilitate diagnosis and treatment of in the future.

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.

Somatic/gonadal mosaicism for structural autosomal rearrangements: female predominance among carriers of gonadal mosaicism for unbalanced rearrangements

Background

Mosaicism for chromosomal structural rearrangements (Rea) is rare and the timing and mechanisms of mosaic Rea formation, maintenance, and clinical manifestation are poorly understood. To date, there are no published data on the cytogenetic profile of mosaic Reas. The question as to whether the proportion of abnormal cells in the carrier’s cultured blood is clinically significant remains unanswered. A previous study showed a strong female preponderance among carriers of mosaicism for Rea with pericentromeric breaks, indicating female-specific instability in early embryos. However, there is no corresponding study on male to female sex ratio (SR) among carriers of somatic and/or gonadal mosaicism for non-centromeric Rea. Population rates of mosaic Rea carriers calculated from consecutive series of patients referred for various reasons and from prenatal samples have not been established. Therefore the objectives of the present study were several-fold: (1) a study on profiles of Rea involved, (2) comparative analysis of the proportion of cells with unbalanced Rea in blood cultures from asymptomatic and affected carriers, (3) comparative analysis of SR in carriers of mosaicism for balanced and unbalanced Rea, and (4) determination of the population frequency of mosaicism for autosomal Rea.

Results

One hundred and three cases of mosaicism for autosomal non-centromeric Rea (N/Rea; normal line/structural rearrangement) in which the sex of the carrier had been specified were identified in the literature. Among balanced Rea, there was a prevalence of reciprocal translocations (89 %) over inversions (11 %). Among unbalanced Rea, deletions were the most frequent (40 %), followed by duplications (25 %) and rings (16 %). Derivatives and other chromosome abnormalities were less frequent (9 and 10 %). Eight of eleven (73 %) affected carriers of unbalanced Rea displayed a high proportion (>50 %) of abnormal cells compared to 4/37 (11 %) in asymptomatic carriers, p < 0.0001. Among carriers of mosaicism for balanced Rea there was a slight male predominance, 24 M/22 F, unlike the strong female predominance among carriers of mosaicism for unbalanced Rea, 11 M/46 F, p < 0.0001. Among ten carriers of unbalanced Rea with reproductive failure, only one was a male with infertility, and one was a partner of a woman experiencing recurrent spontaneous abortion. Population rates of mosaics for reciprocal translocaton (N/rcp), inversion (N/inv), and unbalanced Rea (N/unbal Rea) calculated from published data on consecutive series of patients with reproductive failures were 0.02 ‰, 0.005 ‰, and 0.002 ‰, correspondingly. Among 30,376 infertile patients three carriers of mosaicism for balanced Rea were identified (two cases of N/rcp and one case of N/inv), whereas among 26,384 patients with habitual abortion seven carriers were detected (five N/rcp and two N/inv). Among all 56,760 tested patients with reproductive failures only one was found to be a carrier of mosaicism for an unbalanced Rea (N/del, mosaicism for deletion).

Conclusions

A high proportion of Rea cells (>50 %) detected in cultured T-lymphocytes is associated with clinical manifestation of chromosomal imbalance. A strong female prevalence among carriers of mosaicism for unbalanced Rea suggests male-specific selection against abnormal cells rather than impairment of male gametogenesis, as the latter suggests a better prognosis for male fetuses. These findings should be taken into consideration when genetic counseling of patients referred after a diagnosis of mosaicism for an unbalanced rearrangement in a fetus.

Reproductive and obstetric outcomes in mosaic Turner's Syndrome: a cross-sectional study and review of the literature

BACKGROUND

Turner's syndrome (TS) is depicted as a total or partial absence of one X chromosome that results in ovarian dysgenesis. Chances of spontaneous pregnancy in TS are rare and the outcome of the pregnancies is known to be poor with an increased risk of miscarriage and stillbirths. Our aim is to evaluate reproductive and obstetric outcomes of natural conception and in-vitro fertilization (IVF) cycles in mosaic TS patients.

METHODS

A total of 22 mosaic TS cases (seventeen 45,X/46,XX and five 45,X/46,XX/47,XXX karyotypes) were evaluated.

RESULTS

Live birth and abortion rates were found as 32.7 % and 67.3 %, respectively in 52 pregnancies. Implantation, clinical pregnancy and take home baby rates were detected as 3.7 %, 8.6 % and 5.7 %, respectively per IVF cycle as a result of 35 cycles. Fecundability analysis revealed that 5 % of the cases experienced first pregnancy within 6 months and 8 % within the first 2 years. Mosaicism ratio did not have an effect on the time to the first pregnancy (p = .149).

CONCLUSION

Only a small proportion of the mosaic TS patients conceive in the first 2 years of the marriage. Age of menarche and age of marriage appear not to have any impact on the chance of conceiving. Mosaic TS cases should counseled about the low odds of pregnancy and high miscarriage rates.

Low-level 45,X/46,XX mosaicism is not associated with congenital heart disease and thoracic aorta dilatation:prospective magnetic resonance imaging and ultrasound study

OBJECTIVE

To establish the prevalence of risk factors for aortic dissection, such as bicuspid aortic valve, aortic coarctation and ascending aorta dilatation, in women with low-level 45,X/46,XX mosaicism undergoing an in-vitro fertilization (IVF) procedure.

METHODS

The study group comprised 25 women with low-level 45,X/46,XX mosaicism (ranging from 3.3% to 10.0%) who were referred to two reproductive medicine units between 2009 and 2013 because of infertility and who underwent subsequent karyotyping. In accordance with the recommendation of the Practice Committee of the American Society for Reproductive Medicine for patients with Turner syndrome (TS), prior to the IVF procedure, all women underwent careful cardiovascular screening for congenital heart disease and thoracic aorta dilatation, including standard cardiac examination, echocardiography and non-contrast cardiac magnetic resonance imaging. Aortic size index (ASI, diameter of the ascending aorta normalized to body surface area) and the prevalence of coarctation of the aorta and of bicuspid aortic valve were compared with findings previously reported in women with TS and the general population.

RESULTS

Bicuspid aortic valve without any stenosis or regurgitation was found in one woman in the study group with low-level 45,X/46,XX mosaicism, a statistically significantly lower prevalence of bicuspid aortic valve than that reported in women with TS. Aortic coarctation was not identified in any individual. The ASI was below the  95th percentile in all cases and the mean value was significantly lower than the mean reference values for both the general population and women with TS.

CONCLUSION

Compared with the general population, the prevalence of risk factors for aortic dissection was not found to be higher in women with low-level 45,X/46,XX mosaicism without any noticeable features except infertility.

Possible influence of menstrual cycle on lymphocyte X chromosome mosaicism

PURPOSE

Estrogens are known to selectively influence cell proliferation. Physiological variations of blood hormone concentration might play a role in regulating the level of X chromosome aneuploidy. In this study we observed the percentages of X aneuploid cells in standard lymphocyte cultures from blood samples obtained in relation to the menstrual cycle, noting whether collection occurred during either the follicular or the luteal phase.

METHODS

A study consisting of 28 women with X mosaicism and recurrent pregnancy loss, and 28 age-matched healthy controls. Cytogenetic studies were carried out on peripheral blood samples according to standard procedures.

RESULTS

A significant difference in the percentage of X aneuploidy was found in blood samples obtained during different phases of the menstrual cycle. In the case group, the mean value of aneuploid cells in the follicular and luteal phase samples was 10.0 and 6.3 % respectively and in the control group, it was 2.8 and 1.0 % (P < 0.0001). The difference in the case group varied between 0 and 8 % (3.6 ± 2.1 %) and in the control group between 0 and 4 % (1.7 ± 1.1 %). The specificity for detecting true X mosaicism was 0.875. We estimate that the initial diagnosis of X mosaicism could be correct in 68 % of patients with recurrent pregnancy loss.

CONCLUSIONS

This observational study establishes that the time of blood sampling in relation to the menstrual cycle can influence lymphocyte X chromosome mosaicism. The results, further proven by additional controlled studies, would have practical implications for genetic counselling and fertility treatment.

Reprogenetics: Preimplantational genetics diagnosis

Preimplantational Genetics Diagnosis (PGD) is requested by geneticists and reproductive specialists. Usually geneticists ask for PGD because one or both members of the couple have an increased genetic risk for having an affected offspring. On the other hand, reproductive specialists ask for embryo aneuploidy screening (PGS) to assures an euploid embryo transfer, with the purpose to achieve an ongoing pregnancy, although the couple have normal karyotypes. As embryonic aneuploidies are responsible for pre and post implantation abortions, it is logical to considerer that the screening of the embryonic aneuploidies prior to embryo transfer could improve the efficiency of the in vitro fertilization procedures. Nevertheless, it is still premature to affirm this until well-designed clinical trials were done, especially in women of advanced age where the rate of embryos with aneuploidies is much greater. Although the indications of PGD are similar to conventional prenatal diagnosis (PND), PGD has less ethical objections than the PND. As with the PGD/PGS results only unaffected embryos are transferred, both methods can avoid the decision to interrupt the pregnancy due to a genetic problem; this makes an important difference when compared to conventional prenatal diagnosis.

Relevance of genetic investigation in male infertility

Genetic causes can be directly responsible for various clinical conditions of male infertility and spermatogenic impairment. With the increased use of assisted reproduction technologies our understanding of genetic basis of male infertility has large implications not only for understanding the causes of infertility but also in determining the prognosis and management of such couples. For these reasons, the genetic investigations represent today an essential and useful tool in the treatment of male infertility. Several evidences are available for the clinical practice regarding the diagnosis; however, there are less information relative to the treatment of the genetic causes of male infertility. Focus of this review is to discuss the main and more common genetic causes of male infertility to better direct the genetics investigation in the treatment of spermatogenic impairment.

Clinical genetic testing for male factor infertility: current applications and future directions

Spermatogenesis involves the aggregated action of up to 2300 genes, any of which, could, potentially, provide targets for diagnostic tests of male factor infertility. Contrary to the previously proposed common variant hypothesis for common diseases such as male infertility, genome-wide association studies and targeted gene sequencing in cohorts of infertile men have identified only a few gene polymorphisms that are associated with male infertility. Unfortunately, the search for genetic variants associated with male infertility is further hampered by the lack of viable animal models of human spermatogenesis, difficulty in robustly phenotyping infertile men and the complexity of pedigree studies in male factor infertility. In this review, we describe basic genetic principles involved in understanding the genetic basis of male infertility and examine the utility and proper clinical use of the proven genetic assays of male factor infertility, specifically Y chromosome microdeletions, chromosomal translocations, karyotype, cystic fibrosis transmembrane conductance regulator mutation analysis and sperm genetic tests. Unfortunately, these tests are only able to diagnose the cause of about 20% of male factor infertility. The remainder of the review will be devoted to examining novel tests and diagnostic tools that have the potential to explain the other 80% of male factor infertility that is currently classified as idiopathic. Those tests include epigenetic analysis of the spermatozoa and the evaluation of rare genetic variants and copy number variations in patients. Success in advancing to the implementation of such areas is not only dependent on technological advances in the laboratory, but also improved phenotyping in the clinic.

Unusual maternal uniparental isodisomic x chromosome mosaicism with asymmetric y chromosomal rearrangement

Infertile men with azoospermia commonly have associated microdeletions in the azoospermia factor (AZF) region of the Y chromosome, sex chromosome mosaicism, or sex chromosome rearrangements. In this study, we describe an unusual 46,XX and 45,X mosaicism with a rare Y chromosome rearrangement in a phenotypically normal male patient. The patient's karyotype was 46,XX[50]/45,X[25]/46,X,der(Y)(pter→q11.222::p11.2→pter)[25]. The derivative Y chromosome had a deletion at Yq11.222 and was duplicated at Yp11.2. Two copies of the SRY gene were confirmed by fluorescence in situ hybridization analysis, and complete deletion of the AZFb and AZFc regions was shown by multiplex-PCR for microdeletion analysis. Both X chromosomes of the predominant mosaic cell line (46,XX) were isodisomic and derived from the maternal gamete, as determined by examination of short tandem repeat markers. We postulate that the derivative Y chromosome might have been generated during paternal meiosis or early embryogenesis. Also, we suggest that the very rare mosaicism of isodisomic X chromosomes might be formed during maternal meiosis II or during postzygotic division derived from the 46,X,der(Y)/ 45,X lineage because of the instability of the derivative Y chromosome. To our knowledge, this is the first confirmatory study to verify the origin of a sex chromosome mosaicism with a Y chromosome rearrangement.

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

OBJECTIVE

To explore that it is necessary to routinely detect chromosomes in fertile couples, we detected peripheral blood lymphocyte karyotype in 14965 infertile couples living in Central China and analyzed the incidence and type of chromosomal anomaly.

METHODS

G-banding karyotype analysis of peripheral blood lymphocytes was performed in 14965 couples who went to the outpatient department of our reproductive medical center for counseling on infertility between January 2004 and December 2011. Semen analysis was performed three times in all the men from the 14965 couples.

RESULTS

The rate of chromosomal anomaly in the 14965 infertile couples was 3.84 % (1150/29930). The rate of chromosomal anomaly in the men from 14965 couples was 6.84 % (1024/14965) and in the women 0.84 % (126/14965). The rates of chromosomal anomaly were 1.69 % in normal semen group, 11.82 % in light oligo-astheno-spermis group, 6.58 % in moderate to severe olig-astheno-spermia group and 17.26 % in azoospermia group.

CONCLUSION

Since the rates of chromosomal anomaly are 1.69 % and 11.82 % even in normal semen group and light oligo-astheno-spermia group, respectively, it is necessary to detect peripheral blood lymphocyte karyotype in all infertile couples.

45,X mosaicism in northeast China: a clinical report and review of the literature

Purpose

To explore the prevalence and clinical features, especially the reproductive function, of 45,X mosaicism patients in northeast China.

Methods

GTG-banding was performed on a series of 2,250 patients from our genetic counseling clinic. Each of these patients underwent a physical examination and was interviewed about their medical history and reproductive problems. Literature on 45,X mosaicism was accessed using PubMed and reviewed.

Results

The prevalence of 45,X mosaicism in northeast China is 0.36 % (8/2250), and the mosaic karyotype of our study accounted for 61.54 % (8/13) of Turner syndrome cases. This is comparable with studies from Asia, Europe, South America and other regions. The affected patients showed genital abnormalities, abnormal pregnancy or infertility.

Conclusion

45,X mosaicism is commonly seen in the genetic counseling clinic. Extensive cytogenetic assessment may improve the detection rate in patients with congenital dysplasia, or history of abnormal pregnancy or infertility. Karyotyping plays a key role in prognosis and assisted reproduction or early surgical treatment.

The epidemiology and etiology of azoospermia

The misconception that infertility is typically associated with the female is commonly faced in the management of infertile men. It is uncommon for a patient to present for an infertility evaluation with an abnormal semen analysis report before an extensive female partner workup has been performed. Additionally, a man is usually considered fertile based only on seminal parameters without a physical exam. This behavior may lead to a delay in both the exact diagnosis and in possible specific infertility treatment. Moreover, male factor infertility can result from an underlying medical condition that is often treatable but could possibly be life-threatening. The responsibility of male factor in couple's infertility has been exponentially rising in recent years due to a comprehensive evaluation of reproductive male function and improved diagnostic tools. Despite this improvement in diagnosis, azoospermia is always the most challenging topic associated with infertility treatment. Several conditions that interfere with spermatogenesis and reduce sperm production and quality can lead to azoospermia. Azoospermia may also occur because of a reproductive tract obstruction. Optimal management of patients with azoospermia requires a full understanding of the disease etiology. This review will discuss in detail the epidemiology and etiology of azoospermia. A thorough literature survey was performed using the Medline, EMBASE, BIOSIS, and Cochrane databases. We restricted the survey to clinical publications that were relevant to male infertility and azoospermia. Many of the recommendations included are not based on controlled studies.

Cytogenetic abnormalities in 222 infertile men with azoospermia and oligospermia in Iran: Report and review

BACKGROUND:

Infertility affects approximately 10%-15% of couples in reproductive age. In half of the couples, causes are male-related, associated with impaired spermatogenesis. There is a complex correlation between genetics and infertility. Several factors affect on gametogenesis, from which factors that lead to chromosomal abnormalities are one of the best known. The aim of this study was to determine type and rate of chromosomal abnormalities in infertile azoospermic and oligospermic males in Iranian population.

MATERIALS AND METHODS:

The records of a total of 222 participants were evaluated retrospectively.

RESULTS:

As a whole we observed 13.96% chromosomal abnormality, from which 12.15% showed numerical and 1.8% showed structural abnormalities.

CONCLUSION:

Comparison of our results with the review of the literature shows a higher incidence (4- fold) of gonosomal, in particular, numerical gonosomal, chromosomal anomalies. Cytogenetic analysis is strongly suggested for infertile men, particularly in those who suffer from azoospermia.

Chromosome abnormalities in Indonesian patients with short stature

Background

Short stature is associated with several disorders including wide variations of chromosomal disorders and single gene disorders. The objective of this report is to present the cytogenetic findings in Indonesian patients with short stature.

Methods

G-banding and interphase/metaphase FISH were performed on short stature patients with and without other clinical features who were referred by clinicians all over Indonesia to our laboratory during the year 2003–2009.

Results

The results of chromosomal analysis of ninety seven patients (mean age: 10.7 years old) were collected. The group of patients with other clinical features showed sex chromosome abnormalities in 45% (18/40) and autosomal abnormalities in 10% (4/40), whereas those with short stature only, 42.1% (24/57) had sex chromosome abnormalities and 1.75% (1/57) had autosomal abnormalities. The autosomal chromosomal abnormalities involved mostly subtelomeric regions. Results discrepancies between karyotype and FISH were found in 10 patients, including detection of low-level monosomy X mosaicism in 6 patients with normal karyotype, and detection of mosaic aneuploidy chromosome 18 in 1 patient with 45,XX,rob(13;14)(q10;q10).

Statistical analysis showed no significant association between the groups and the type of chromosomal abnormalities.

Conclusion

Chromosome abnormalities account for about 50% of the short stature patients. Wide variations of both sex and autosomal chromosomes abnormalities were detected in the study. Since three out of five patients had autosomal structural abnormalities involving the subtelomeric regions, thus in the future, subtelomeric FISH or even a more sensitive method such as genomic/SNP microarray is needed to confirm deletions of subtelomeric regions of chromosome 9, 11 and 18. Low-level mosaicism in normal karyotype patients indicates interphase FISH need to be routinely carried out in short stature patients as an adjunct to karyotyping.

Emerging evidence for the role of genomic instability in male factor infertility

Male infertility is a common and complex pathology affecting about 7% of men of reproductive age. Given its complexity, the underlying etiology for male infertility is often unknown. A growing amount of evidence suggests genomic instability may be an important factor in some cases of male factor infertility. While some specific manifestations of genomic instability, such as increased sperm aneuploidy rates and increased somatic translocations and inversions in infertile men, are well established, other facets of genomic instability associated with male infertility have not been thoroughly investigated. A limited body of recent work has identified a potential association between microsatellite instability and spermatogenic failure. In addition, mutations in mismatch repair and tumor suppressor genes, which could potentially lead to genomic instability, have been identified in some infertile men and animal models. In addition, results of two epidemiologic studies suggest spermatogenic defects might be just one aspect of a more systemic problem, possibly due to increased genomic instability. In this review we discuss well-established links between genomic instability and male infertility, as well as some of the emerging but less established data to support this relationship. We also propose some important areas of future research toward a more complete understanding of the underlying mechanisms for male infertility.

Chromosome analysis by spectral karyotyping of spermatozoa from an oligoasthenozoospermic carrier of a 10; 21 reciprocal translocation

Cytogenetic analysis of germ-line cells prior to intracytoplasmic sperm injection (ICSI) treatment is thought to be necessary for infertile males with an identified chromosomal abnormality. We analyzed the chromosomal karyotype of human spermatozoa from an oligoasthenozoospermic carrier of a reciprocal translocation t(10; 21). Cytogenetic analysis of 39 spermatozoa was performed by spectral karyotyping (SKY) and by ICSI into mouse oocytes. The motile morphologically normal spermatozoa were injected into mouse oocytes. Of these spermatozoa, 38 (97.4%) were activated. Twenty-one (53.8%) of the activated oocytes formed two pronuclei. Metaphase chromosome spreads from 13 spermatozoa were analyzed. Only one spermatozoon was normal and 2 spermatozoa exhibited balanced translocation. Nine and one spermatozoa showed abnormalities related and unrelated to the translocation, respectively. The numbers of normal/balanced spermatozoa were lower than those in previous reports analyzing reciprocal translocations using a previously described technique involving penetrated golden hamster oocytes. After genetic counseling with the carrier and his partner, ICSI treatment was performed. Healthy female and male infants were delivered at 37 weeks gestation via a Caesarean section. The female infant was a carrier of the reciprocal translocation and the male infant was confirmed normal on prenatal diagnosis at 16 weeks gestation. For genetic counseling prior to ICSI treatment, the incidence of unbalanced type spermatozoa after swim-up or Percoll gradient treatment should be investigated and discussed with couples having fertility problems related to oligozoospermia autosomal structural abnormalities.

Cytogenetic findings and reproductive outcome of infertile couples referred to an assisted reproduction program

It is still undefined whether all the couples entering an assisted reproduction program should undergo to karyotype analysis. The present study was conducted to determine the prevalence of chromosomal abnormalities in a non-selected sample of 1,146 couples referred to assisted reproduction technologies (ART), and to analyze the outcome of pregnancies from couples in whom cytogenetic anomalies were detected. Irrespective of the infertility factor, fertilization was achieved by intracytoplasmic sperm injection (ICSI). A total number of 35 karyotype anomalies were diagnosed, corresponding to an abnormality frequency of 1.52% (1.83% for men and 1.22% for women). As could be expected, the majority of men presenting karyotype anomalies had a low sperm count. Among women, the majority of cytogenetic anomalies were detected in individual not presenting risk factors for aberrant karyotype. Around 41% of pregnancies achieved in couples presenting chromosomal anomalies ended in spontaneous abortion. Information on fetal karyotype was limited. No major malformations were observed among newborns from parents with abnormal karyotype. In consideration of the elevated frequency of pregnancy loss, it seems advisable to recommend that chromosomal analysis be performed in all couples undergoing ART. This with the aim of identifying patients that would possibly benefit from pre-implantation genetic diagnosis.

Genetic screening in Italian infertile couples undergoing intrauterine insemination and in vitro fertilization techniques: a multicentric study

AIM OF THE STUDY

To report the frequency of aberrant karyotype and mutated cystic fibrosis transmembrane conductance regulator (CFTR) gene, according to a careful application of Italian guidelines for genetic screening in infertile couple candidates for intrauterine insemination (IUI) and in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI).

MATERIALS AND METHODS

Two thousand and sixteen consecutive infertile couple candidates for Assisted Reproduction Techniques (ART) were screened for karyotype and 616 couples for CFTR analysis.

RESULTS

Regarding karyotype analysis, 59 chromosomal abnormalities were diagnosed in candidates for IVF/ICSI: 27 mutations in women corresponding to a frequency equal to 1.53% (27/1762; 95% confidence interval [CI], 0.96-2.1%) and 32 mutations in men corresponding to a frequency equal to 1.82% (32/1762; 95% CI, 1.2-2.44%) for men. The frequency differs according to the sperm count. In couple candidates for IUI techniques, no genetic abnormalities were found in male patients and only one aberration in a female patient with a frequency of 0.41% (1/245 CI 0.01-0.81%). Regarding CFTR analysis, excluding the 5T variant, we obtained 20 mutations in couples undergoing IVF/ICSI and 8 mutations in IUI group.

CONCLUSION

Couples undergoing IVF/ICSI show a higher prevalence of aberrant karyotypes than general population, whereas the frequency of a mutation of the CFTR gene is similar. On the other hand, couples undergoing IUI do not differ from the general population either for karyotype or for CFTR mutations.

Genetische Risiken der assistierten Reproduktion

Kinderwunschpatienten müssen vor einer Behandlung über die genetischen Risiken individuell beraten werden. Chromosomenanomalien sind für etwa 5% der männlichen Subfertilität verantwortlich. Im Fall einer Azoospermie liegt die Rate bei 15%. Daher sollte bei einer männlichen Subfertilität bei einer Spermienzahl <20 Mio./ml eine Chromosomenanalyse bei beiden Partnern durchgeführt werden, da ein erhöhtes Risiko für genetische Veränderungen besteht. Ein Klinefelter-Syndrom oder eine Robertson-Translokation können für eine männliche Subfertilität verantwortlich sein. Mutationen des CFTR-Gens sowie Veränderungen des Y-Chromosoms findet man gehäuft bei männlicher Subertiltät. Mikrodeletionen treten am häufigsten am langen Arm des Y-Chromosoms auf (Yq) und betreffen Gene, die direkt in die Spermatogenese involviert sind, insbesondere das AZF-Gen.

Bezüglich Schwangerschaftsverlauf und neonatalem Outcome der Kinder müssen Kinderwunschpatienten darüber aufgeklärt werden, dass während der Schwangerschaft und der Geburt häufiger Komplikationen auftreten als nach Spontankonzeption. Das Fehlgeburtsrisiko ist um das 1,3-Fache erhöht, dies ist jedoch vermutlich Folge der Subfertilität sowie weiterer Risikofaktoren, die die Paare mitbringen, und nicht Folge der Therapie. Das Risiko für Schwangerschaftskomplikationen wie Präeklampsie, Wachstumsretardierung und Totgeburt ist ebenfalls erhöht. Zudem ist das Fehlbildungsrisiko sowohl bei der IVF-Therapie als auch bei der ICSI-Therapie um das 1,3-Fache erhöht.

Rate of X chromosome aneuploidy in young fertile women: Comparison of cultured and uncultured cell preparations using fluorescence in situ hybridisation

BACKGROUND

X chromosome aneuploidy <10% in female patients is a routinely used reporting limit in diagnostic cytogenetics. X aneuploidy (<10%) is commonly detected in women investigated for infertility or recurrent miscarriages. It is unclear if this aneuploidy is causally relevant or related to the culture process. Information about the background rate of X aneuploidy in young fertile women would be helpful in resolving this issue.

AIM

This study aimed to investigate the rate of X aneuploidy in young fertile women in cultured and uncultured samples to determine if the commonly used <10% limit is relevant.

METHOD

Volunteers (aged 22-40 years) with proven fertility (n = 78) participated. The number of X chromosome signals in 500 cultured and 500 uncultured preparations were enumerated using FISH.

RESULTS

Significantly, all participants had <5% X aneuploidy in both preparations, X chromosome loss occurred (2.4%) more frequently than gain (0.7%). Cultured preparations had a mean of 2.1% cells with X chromosome aneuploidy (95% CI 1.9-2.3%) compared with a mean rate of 0.9% aneuploidy in uncultured preparations (95% CI 0.7-1.1%). The relative risk for cultured preparations having X aneuploidy compared with uncultured cells was 2.33 (P < 0.001) (95% CI 2.1-2.6).

CONCLUSION

Young fertile women had <5% X aneuploidy. The rate of X aneuploidy was higher in cultured (2.1%) compared with uncultured (0.9%) preparations (P < 0.001). This data may provide useful background information when considering low level X aneuploidy in other groups of women with clinical indications for karyotype.

Sex chromosome micromosaicism in infertile men with normal karyotypes

OBJECTIVE

To define the prevalence of low-level sex chromosome mosaicism in a cohort of infertile men.

DESIGN

Prospective cohort study of infertile men.

SETTING

Tertiary university infertility center.

PATIENT(S)

One hundred one consecutive men who presented with primary infertility for evaluation.

INTERVENTION(S)

Fluorescent in situ hybridization for X and Y was performed on 200 cells, and if an aberrant sex chromosome complement was noted, 400 cells were counted. For this study, any abnormality in sex chromosome complement was defined as micromosaicism.

MAIN OUTCOME MEASURE(S)

Low-level sex chromosome mosaicism.

RESULT(S)

Sixty-seven of these men (67%) had no mosaicism, and 34 men (34%) had micromosaicism. The median percentage of abnormal chromosomes in these men was 2%. The mean age of the men without micromosaicism was lower than for men with micromosaicism (31.1 years vs. 35.2 years). A trend toward higher FSH levels in men with low-level mosaicism was seen. Median sperm density and percent motility were higher in normal men. Percent normal morphology was identical between groups.

CONCLUSION(S)

We found low-level sex chromosome mosaicism in 34% of infertile men who presented for evaluation. Men with low-level mosaicism were significantly older. Low-level mosaicism may emerge with advancing age and may therefore help to explain the decline in fertility potential seen in older men.

[Exploration of testicular function]

The main endocrine function of the testis after puberty is testosterone production. In most cases, hypogonadism in adult men can be diagnosed by determining total testosterone concentration. Due to the circadian rhythm of testosterone secretion, blood samples should be extracted early in the morning. The results of commercially available methods for analysis show considerable variability. Furthermore, the threshold for the symptoms of hypogonadism may differ in each individual. For these reasons, moderately low testosterone levels should be interpreted with caution before a diagnosis of hypogonadism can be established. In these cases, determination of either free or bioavailable testosterone can be useful. Direct methods can be used or the respective concentrations can be calculated on the basis of total testosterone and sex hormone-binding globulin (SHBG). This latter method is easy to perform but the results are less reliable. Endocrinological evaluation of the testes should also include analysis of the gonadotropins (follitropin [FSH] and lutropin [LH]), which are described in another article in this series. Inhibin B is a biological marker of the amount and the physiological status of Sertoli cells in the postpubertal testis. Inhibin B may improve the information given by FSH for the determination of spermatogenic reserve in non-obstructive azoospermia, but determination of this glycoprotein is not currently used for routine assessment. The most important laboratory test to study reproductive function in men is semen analysis. However, the predictive power of this test is limited by the analytical imprecision of current methods, all of which are manual, and by the biological variability of most of their components. Special attention should be paid to pre-analytical procedures, because they require the understanding and participation of the patient. Some organizations and societies have proposed standardized methods to help improve the quality of semen analysis and reliable exchange of the results of seminogram. Biochemical markers of the prostate, seminal vesicles and epididymis in seminal plasma can indicate the level of damage in hypospermia or azoospermia. The fertility potential of sperm cells can be investigated with a variety of tests and assays, but none of them can yet be recommended for routine practice. Congenital hypogonadism is frequently caused by chromosome abnormalities, particularly sex chromosomal aneuploidies. Other causes of infertility include structural aberrations of autosomes. The main cytogenetic technique performed to determine chromosome constitution is karyotyping. To detect submicroscopic defects, this test can be performed in conjunction with fluorescent in situ hybridization (FISH).

GENETIC ANOMALIES DETECTED IN PATIENTS WITH NON-OBSTRUCTIVE AZOOSPERMIA AND OLIGOZOOSPERMIA

Genetic factors have a major importance in male infertility etiology. Numerical and structural chromosomal abnormalities seem to be frequent inoligospermia and azoospermia cases with unknown etiology. In this study, 819 patients with azoospermia (383) and oligospermia (436) who attended the infertility department between 1995-2005 were evaluated. Spermogram and basic hormone proties (FSH-testosterone) were studied two times in a one month interval from each patient, and all the cases were evaluated cytogenetically. The 47 (12%) of 383 azoospermia patients and the 20 (4%) of 436 oligospermia patients were found to have chromosomal abnormalities. The 9 (19%) of the chromosomal abnormalities found in azoospermia patients were autosomal and the 38 (80%) were gonosomal. In oligospermia cases, the 8 (40%) of the chromosomal abnormalities were autosomal and 12 (60%) were gonosomal. Cytogenetic analysis and genetic counseling would be helpful in infertile males with azoospermia and oligospermia by determining the genetic factors causing infertility and by assessing the genetic risks of the offsprigs provided by assisted reproductive techniques.

Cytogenetic abnormalities in 179 cases with male infertility in Western Region of Turkey: report and review

PURPOSE

In this study we aimed to evaluate the postnatally screened karyotype results in couples who were referred because of primary infertility between 2000 and 2006 in Izmir.

METHODS

The records of a total of 179 cases were evaluated retrospectively.

RESULTS

A total of 21 cases (11.74%) showed chromosomal alteration. Thirteen (7.26%) were 47,XXY; three (1.68%) were pericentric inversion of chromosome 9; one (0.56%) 46,XY/45,XO; one (0.56%) 46,XY/47,XXY/48,XXXY; one (0.56%) 46,XY,t(X;1); one (0.56%) 46,XY/46,XY,del(Y)(q11.2) and one (0.56%) 46,XX.

CONCLUSIONS

The rate of gonosomal chromosomal abnormalities was nearly three times higher in our region than the rate in the literature. Chromosomal analysis is strongly suggested particularly in those who suffer fertility problems.

Genetic counseling in Robertsonian translocations der(13;14): frequencies of reproductive outcomes and infertility in 101 pedigrees

Robertsonian translocations 13/14 are the most common chromosome rearrangements in humans. However, most studies aimed at determining risk figures are more than 20 years old. Their results are often contradictory regarding important topics in genetic counseling such as infertility and unfavorable pregnancy outcomes. Here, we present a study on a sample of 101 previously unreported pedigrees of der(13;14)(q10;q10). In order to minimize problems of partial ascertainment, we included families with a wide range of reasons of ascertainment such as birth of a child with congenital anomalies, prenatal diagnosis due to maternal age, fertility problems and recurrent pregnancy loss. No evidence of increased infertility rates of female and male carriers was found. The detected miscarriage frequency of female carriers was higher than previously reported (27.6 +/- 4.0% of all spontaneous pregnancies). This may be explained by an over-correction of earlier studies, which excluded all unkaryotyped miscarriages. In three out of 42 amniocenteses, translocation trisomies 13 were diagnosed (7.1 +/- 4.0% of all amniocenteses). The frequency of stillbirths was 3.3 +/- 1.6% for female carriers and 1.4 +/- 1.4% for male carriers. A low risk for the live birth of translocation trisomy 13 children was confirmed since no live born children with trisomy 13 or Pätau syndrome were detected in the ascertainment-corrected sample.

Underlying karyotype abnormalities in IVF/ICSI patients

Cytogenetic investigations are performed in couples asking for IVF or intracytoplasmic sperm injection (ICSI) treatment. These serve a diagnostic purpose because male or female infertility might have a chromosomal origin. Chromosomal aberrations found in these patients include numerical abnormalities, such as Klinefelter syndrome, XYY karyotype or Turner syndrome and its variants; sex reversions, such as XX males or XY females; and also structural abnormalities, such as Robertsonian or reciprocal translocations and inversions. Finding the chromosomal origin of infertility in a patient also has a prognostic value because it aids the management of pregnancies obtained after IVF or ICSI and may lead to a proposal of prenatal or preimplantation genetic diagnosis.

Genetic screening in 2,710 infertile candidate couples for assisted reproductive techniques: results of application of Italian guidelines for the appropriate use of genetic tests

OBJECTIVE

To report the results of the routine application of Italian guidelines that apply to infertile patient candidates for any assisted reproduction technique (ART). The guidelines recommend performing a karyotype analysis in each couple and the screening test for mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) in one of the two partners.

DESIGN

Case series.

SETTING

Infertility unit.

PATIENT(S)

Two thousand seven hundred ten consecutive infertile couple candidates for ART.

INTERVENTION(S)

Peripheral blood evaluation of karyotype and CFTR gene.

MAIN OUTCOME MEASURE(S)

Frequency of aberrant karyotype and mutated CFTR gene.

RESULT(S)

A total of 74 aberrant karyotypes were diagnosed, corresponding to 1.3% (95% confidence interval [CI], 0.9%-1.7%) in women and to 1.5% (95% CI, 1.0%-2.0%) in men. In men, the frequency of chromosomal abnormalities differed according to the treatment group (0.3%, 1.1%, and 2.2% in IUI, IVF, and ICSI, respectively). The same was not observed in women. Excluding the 5T variant, 3.8% of the screened patients showed a mutated CFTR gene (95% CI, 3.1%-4.5%), and the mutation was found in both partners in 0.2% of the couples (95% CI, 0.0-0.4%).

CONCLUSION(S)

The frequency of aberrant karyotypes is higher in infertile couples than in the general population, whereas the frequency of a mutation of the CFTR gene is similar.

Cytogenetic and molecular characterization of the derivative Y chromosome: a case study of an azoospermic patient

The success of infertility treatment depends on the underlying cause and severity of the infertility problem. The current report addresses the complex genotype-phenotype interactions in an azoospermic man. Cytogenetic, molecular cytogenetic and molecular genetic studies indicated the derivative monocentric Y chromosome with duplication of Yp11 (including SRY gene) and partial deletion of Yq11 (including azoospermia factor - AZFb-c regions) as the most probable cause of the severe testicular failure. Our study emphasizes the importance of detailed genetic analysis in male infertility evaluation and helps to estimate the outcome of infertility treatment.