Clinical data for 185 infertile Iranian men with Y-chromosome microdeletion

An analysis of Y-chromosome microdeletion in infertile Korean men with severe oligozoospermia or azoospermia

PURPOSE

Infertility affects 10% to 15% of couples, and male factor accounts for 50% of the cases. The relevant male genetic factors, which account for at least 15% of male infertility, include Y-chromosome microdeletions. We investigated clinical data and patterns of Y-chromosome microdeletions in Korean infertile men.

MATERIALS AND METHODS

A total of 919 infertile men whose sperm concentration was ≤5 million/mL in two consecutive analyses were investigated for Y-chromosome microdeletion. Among them, 130 infertile men (14.1%) demonstrated Y-chromosome microdeletions. Medical records were retrospectively reviewed.

RESULTS

In 130 men with Y-chromosome microdeletions, 90 (69.2%) had azoospermia and 40 (30.8%) had severe oligozoospermia. The most frequent microdeletions were in the azoospermia factor (AZF) c region (77/130, 59.2%), followed by the AZFb+c (30/130, 23.1%), AZFa (8/130, 6.2%), AZFb (7/130, 5.4%), AZFa+b+c (7/130, 5.4%), and AZFa+c (1/130, 0.7%) regions. In men with oligozoospermia, 37 (92.5%) had AZFc microdeletion. Chromosomal abnormalities were detected in 30 patients (23.1%). Higher follicle-stimulating hormone level (23.2±13.5 IU/L vs. 15.1±9.0 IU/L, p<0.001), higher luteinizing hormone level (9.7±4.6 IU/L vs. 6.0±2.2 IU/L, p<0.001), and lower testis volume (10.6±4.8 mL vs. 13.3±3.8 mL, p<0.001) were observed in azoospermia patients compared to severe oligozoospermia patients.

CONCLUSIONS

Y-chromosome microdeletion is a common genetic cause of male infertility. Therefore, Y-chromosome microdeletion test is recommended for the accurate diagnosis of men with azoospermia or severe oligozoospermia. Appropriate genetic counseling is mandatory before the use of assisted reproduction technique in men with Y-chromosome microdeletion.

A novel missense variant in CDK5RAP2 associated with non-obstructive azoospermia

OBJECTIVE

The most severe type of male infertility is non-obstructive azoospermia (NOA), where there is no sperm in the ejaculate due to failure of spermatogenesis, affecting 10%-20% of infertile men with azoospermia. Genetic studies have identified dozens of NOA genes. The main aim of the present study is to identify a novel monogenic mutation that may cause NOA.

MATERIALS AND METHODS

We studied the pedigree of a consanguineous family with three NOA and one fertile brother by a family-based exome-sequencing, segregation analysis, insilico protein modeling and single-cell RNA sequencing data analysis.

RESULTS

Bioinformatics analysis followed by sanger sequencing revealed that three NOA brothers were homozygous for a rare missense variant in Cyclin Dependent Kinase Regulatory Subunit Associated Protein 2 (Centrosomin) CDK5RAP2 (NM_018249:exon26:c.A4003T:p.R1335W, rs761196443). Protein modeling demonstrated that CDK5RAP2, Arg1335Trp resided nearby the Microtubule Associated Protein RP/EB Family Member 1 (EB1/MAPRE1) interaction site. As a consequence of the R1335W mutation, the positively charged Arginine was replaced by to the hydrophobic tryptophan residue, possibly leading to local instability in the structure and perturbation in the CDK5RAP2-MAPRE1 interaction.

CONCLUSION

Our study reports a novel missense variant of CDK5RAP2 that segregates in homozygosity with male infertility and NOA in a consanguineous family. In silico structural predictions and gene expression data indicate a potential role of the CDK5RAP2 variant in causing defective centrosomic maturation during spermatogenesis.

High incidence of AZF duplications in clan-structured Iranian populations detected through Y chromosome sequencing read depth analysis

The ampliconic region of the human Y chromosome consists of large duplicated sequences that can undergo non-allelic homologous recombination (NAHR), resulting in structural rearrangements that may cause infertility, especially when they occur in the azoospermia factor b/c (AZFb/c) region. Although AZF duplications have long been neglected due to the technical limitations of STS-based studies that focused mainly on deletions, recent next generation sequencing (NGS) technologies provided evidence for their importance in fertility. In this study, a NGS read depth approach was used to detect AZFb/c rearrangements in 87 Iranians from different ethnic groups. The duplication frequency in Iran proved to be twice as high as in the "1000 Genomes" dataset. Interestingly, most duplications were found in patrilineal ethnic groups, possibly as a consequence of their lower male effective population size which can counteract negative selection. Moreover, we found a large 8.0 Mb duplication, resulting in a fourfold increase in the copy number of AZFc genes, which to our knowledge is the largest duplication ever reported in this region. Overall, our results suggest that it is important to consider not only AZF deletions but also duplications to investigate the causes of male infertility, especially in patrilineal clan-based populations.

Bridging the Gap between AZF Microdeletions and Karyotype: Twelve Years' Experience of an Infertility Center

PURPOSE

Despite all past efforts, the current guidelines are not explicit enough regarding the indications for performing azoospermia factor (AZF) screening and karyotype, burdening clinicians with the decision to assess whether such tests are meaningful for the infertile male patient. These assessments can be costly and it is up to the healthcare practitioner to decide which are necessary and to weigh the benefits against economic/psychological harm. The aim of this study is to address such gaps and provide update on current management options for this group of patients.

MATERIALS AND METHODS

To address such gaps in male infertility management and to elucidate whether AZF screening is indicated in individuals who concomitantly harbor chromosomal abnormalities we conducted a retrospective cohort analysis of 10,388 consecutive patients with non-obstructive azoospermia (NOA) and severe oligozoospermia.

RESULTS

Previously, it has been suggested that all NOA cases with chromosomal defects, except males with 46,XY/45,X karyotype, have no indication for AZF screening. Our findings revealed that cases carrying the following chromosomal abnormalities inv(Y)(p11.2q12); idic(Y)(q11.2); 46,XY,r(Y); idic(Y)(p11.2) and der(Y;Autosome) (76/169; 44.9%; 95% CI, 37.7-52.5) should also be referred for AZF deletion screening. Here, we also report the correlation between sperm count and AZF deletions as a secondary outcome. In accordance with previously reported data from North America and Europe, our data revealed that only 1% of cases with >1×10⁶ sperm/mL had Y chromosome microdeletions (YCMs).

CONCLUSIONS

In the era of assisted reproduction, finding cost-minimization strategies in infertility clinics without affecting the quality of diagnosis is becoming one of the top prioritized topics for future research. From a diagnostic viewpoint, the results reflect a need to reconsider the different karyotype presentations and the sperm count thresholds in male infertility guidelines as indicators for YCM screening during an infertility evaluation.

Repetitive DNA Sequences in the Human Y Chromosome and Male Infertility

The male-specific Y chromosome, which is well known for its diverse and complex repetitive sequences, has different sizes, genome structures, contents and evolutionary trajectories from other chromosomes and is of great significance for testis development and function. The large number of repetitive sequences and palindrome structure of the Y chromosome play an important role in maintaining the stability of male sex determining genes, although they can also cause non-allelic homologous recombination within the chromosome. Deletion of certain Y chromosome sequences will lead to spermatogenesis disorders and male infertility. And Y chromosome genes are also involved in the occurrence of reproductive system cancers and can increase the susceptibility of other tumors. In addition, the Y chromosome has very special value in the personal identification and parentage testing of male-related cases in forensic medicine because of its unique paternal genetic characteristics. In view of the extremely high frequency and complexity of gene rearrangements and the limitations of sequencing technology, the analysis of Y chromosome sequences and the study of Y-gene function still have many unsolved problems. This article will introduce the structure and repetitive sequence of the Y chromosome, summarize the correlation between Y chromosome various sequence deletions and male infertility for understanding the repetitive sequence of Y chromosome more systematically, in order to provide research motivation for further explore of the molecules mechanism of Y-deletion and male infertility and theoretical foundations for the transformation of basic research into applications in clinical medicine and forensic medicine.

Prevalence of Y chromosome microdeletions among infertile Mongolian men

Y chromosome microdeletions are the second most common genetic cause of male infertility after Klinefelter syndrome. The aim of this study was to determine the patterns of Y chromosome microdeletions among infertile Mongolian men. A descriptive study was performed on 75 infertile men from February 2017 to December 2018. Y chromosome microdeletions were identified by polymerase chain reaction. Semen parameters, hormonal levels, and testis biopsy samples were examined. Among 75 infertile men, two cases of Y chromosome microdeletions were identified. The first case had an AZFa complete deletion and the other had an AZFc partial deletion. This study found that the proportion of Y chromosome microdeletions among infertile Mongolian men was 2.66%. The findings can be applied to in vitro fertilization and assisted reproductive technology, and our results will help clinicians improve treatment management for infertile Mongolian couples.

Abnormal Y chromosome detection in infertile males using multiplex ligation-dependent probe amplification

Y chromosome abnormalities are the leading cause of male infertility. The clinical detection of abnormalities is necessary for appropriate genetic counselling. This study describes the prevalence, distribution and characteristics of Y chromosome abnormalities, which should be considered in the clinical management of infertile males. A total of 121 patients with oligozoospermia, 120 with azoospermia and 88 normal individuals were recruited between June 2019 and July 2021. Y chromosome microdeletions were assessed using multiplex ligation-dependent probe amplification (MLPA). The abnormal Y chromosome prevalence was 30.70%, and it was most common in patients aged 26-40 years. The frequencies of azoospermia factor (AZF) deletion, duplication and deletions/duplications were 19.76%, 9.42% and 1.52% respectively. The most common abnormalities were AZFc deletion (19.80%), AZFc partial deletion (40.59%) and AZFc partial duplication (17.82%). Oligozoospermia was associated with an increased incidence of AZF deletion. In the subgroup analysis, patients <30 years old with azoospermia exhibited elevated follicle-stimulating hormone levels and oestradiol. Moreover, the incidence of AZF deletion was higher in those with azoospermia (OR: 2.12; 95% CI: 1.05-5.28; p = 0.023) or oligozoospermia (OR: 2.54; 95% CI: 1.13-5.79; p = 0.008) than in normal individuals for ages ≥30 years.

microRNAs in the pathogenesis of non-obstructive azoospermia: the underlying mechanisms and therapeutic potentials

miRNAs are involved in different biological processes, including proliferation, differentiation, and apoptosis. Interestingly, 38% of the X chromosome-linked miRNAs are testis-specific and have crucial roles in regulating the renewal and cell cycle of spermatogonial stem cells. Previous studies demonstrated that abnormal expression of spermatogenesis-related miRNAs could lead to nonobstructive azoospermia (NOA). Moreover, differential miRNAs expression in seminal plasma of NOA patients has been reported compared to normozoospermic men. However, the role of miRNAs in NOA pathogenesis and the underlying mechanisms have not been comprehensively studied. Therefore, the aim of this review is to mechanistically describe the role of miRNAs in the pathogenesis of NOA and discuss the possibility of using the miRNAs as therapeutic targets.Abbreviations: AMO: anti-miRNA antisense oligonucleotide; AZF: azoospermia factor region; CDK: cyclin-dependent kinase; DAZ: deleted in azoospermia; ESCs: embryonic stem cells; FSH: follicle-stimulating hormone; ICSI: intracytoplasmic sperm injection; JAK/STAT: Janus kinase/signal transducers and activators of transcription; miRNA: micro-RNA; MLH1: Human mutL homolog l; NF-κB: Nuclear factor-kappa B; NOA: nonobstructive azoospermia; OA: obstructive azoospermia; PGCs: primordial germ cells; PI3K/AKT: Phosphatidylinositol 3-kinase/protein kinase B; Rb: retinoblastoma tumor suppressor; ROS: Reactive Oxygen Species; SCOS: Sertoli cell-only syndrome; SIRT: sirtuin; SNPs: single nucleotide polymorphisms; SSCs: spermatogonial stem cells; TESE: testicular sperm extraction; TGF-β: transforming growth factor-beta.

PPP2R1B is modulated by ubiquitination and is essential for spermatogenesis

The serine-threonine protein phosphatase 2A (PP2A) is a heterotrimeric enzyme complex that regulates many fundamental cellular processes. PP2A is involved in tumorigenesis because mutations in the scaffold subunit, PPP2R1B, were found in several types of cancers. However, the biological function of PPP2R1B remains largely unknown. We report here that homozygous deletion of Ppp2r1b in Mus musculus impairs meiotic recombination and causes meiotic arrest in spermatocytes. Consistently, male mice lacking Ppp2r1b are characterized with infertility. Furthermore, heterozygous missense mutations in the Homo sapiens PPP2R1B gene, which encodes PPP2R1B, are identified in azoospermia patients with meiotic arrest. We found that PPP2R1B mutants are susceptible to degradation by an E3 ligase CRL4A^DCAF6 , and resistant to de-polyubiquitylation by ubiquitin-specific protease 5 (USP5). In addition, heterozygous mutations in PPP2R1B reduce stability of the wild-type PPP2R1B. Our results demonstrate an essential role of PPP2R1B in spermatogenesis and identify upstream regulators of PPP2R1B.

Karyotypic abnormalities and molecular analysis of Y chromosome microdeletion in Iranian Azeri Turkish population infertile men

Infertility is one of the major health-threatening problems in communities which may lead to psychological problems among couples. Y chromosome abnormalities and microdeletions have recently been considered as one of the male infertility factors. The aim of this study was to evaluate different chromosomal disorders and azoospermia factor b (AZFb), AZFc and AZFd microdeletions in idiopathic non-obstructive oligo or azoospermia infertile men. One hundred infertile (78 azoospermia and 22 oligospermia) and 100 fertile men were included in this study. Luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels were evaluated by electrochemiluminescence. Karyotyping was performed according to standard methods and interpreted using the International System for Human Cytogenetic Nomenclature (ISHCN) recommendation. For Y chromosome microdeletion analysis, a multiplex polymerase chain reaction (PCR) was performed using STS primers. Higher FSH (24.32 ± 15.32 versus 8.02 ± 3.37, p < 0.0001) and LH (14.97 ± 8.26 versus 5.42 ± 2.73, p < 0.0001) were observed in infertile patients compared to their fertile counterpart. Additionally, 14% of infertile patients exhibited abnormal karyotype. The  frequency of Y chromosome microdeletions in azoospermic and oligospermic patients was 32.05% (25/78) and 0% (0/22), respectively. Additionally, in azoospermic patients, the highest microdeletion frequency was related to the AZFc region (80%). Our data indicate the presence of chromosomal changes in the most infertile men, suggesting karyotype and molecular analysis of Y chromosome microdeletions for genetic counseling before assisted reproduction.Abbreviations: ART: assisted reproductive technology; AZF: azoospermia factor; DAZ: deleted in azoospermia; FCS: fetal calf serum; FSH: follicle stimulating hormone; LH: luteinizing hormone; PCR: polymerase chain reaction; SRY: sex-determining region Y; STS: sequence-tagged sites.

Sperm retrieval rate and reproductive outcome of infertile men with azoospermia factor c deletion

To evaluate the success rate in sperm retrieval (SR) through microdissection testicular sperm extraction (micro-TESE) in infertile azoospermia factor c (AZFc)-deleted men and determining their reproductive outcomes following ICSI, medical records of couples with AZFc-deleted male partners were reviewed on patient's age, serum hormone levels, karyotype, testicular pathology and pregnancy outcomes. A comparison on age and serum hormone level was conducted between groups with positive and negative sperm retrieval in both azoospermic and oligozoospermic AZFc-deleted men. Of 225 who had AZFc deletion, 195 cases followed clinical treatments. From 195 cases, 116 were azoospermic, 79 were oligozoospermic. Pathology profile was available in 103 of 195 subjects which the predominant trait was SCOS and was seen in 66.9% of cases (69 of 103). Success rate of sperm retrieval in azoospermic patients who underwent micro-TESE was 36.3% (28/77). Forty-three oligozoospermic and 17 azoospermic patients started ART cycle. Pregnancy rate in oligozoospermic group was 35.4% (17 cases), whilst there was no clinical pregnancy in azoospermic group. In conclusion, the pregnancy and delivery in oligozoospermic patients with AZFc deletion are comparable with other studies, but despite of sperm retrieval in azoospermic patients with AZFc deletion, the chance of pregnancy or delivery in these patients was very low.

Detection of Y Chromosome Microdeletions and Hormonal Profile Analysis of Infertile Men undergoing Assisted Reproductive Technologies

Background

Y chromosome deletions (YCDs) in azoospermia factor (AZF) region are associated with ab- normal spermatogenesis and may lead to azoospermia or severe oligozoospermia. Assisted reproductive tech- nologies (ART) by intracytoplasmic sperm injection (ICSI) and testicular sperm extraction (TESE) are com- monly required for infertility management of patients carrying YCDs. The aim of this study was to estimate the frequency of YCDs, to find the most frequent variant in infertile men candidate for ART and to compare YCD distribution with a control fertile group. The semen parameters, hormonal profiles and ART outcomes of the infertile group were studied.

Materials and Methods

This case-control study consisted of 97 oligozoospermic or non-obstructive azoospermic (NOA) infertile men, who had undergone ART, as the case group and 100 fertile men as the control group. DNA samples were extracted from blood samples taken from all 197 participants and YCDs were identified by multiplex polymerase chain reaction (PCR) of eight known sequence-tagged sites. The chi-square test was used to compare the mean values of hormone and sperm parameters between the two groups. P<0.05 was considered statistically significant.

Results

No YCD was detected in the control group. However, 20 out of 97 (20.6%) infertile men had a YCD. AZFc, AZFbc and AZFabc deletions were detected in 15 (75%), four (20%) and one (5%) YCD-positive patients. No fer- tilization or clinical pregnancy was seen following ICSI in this sub-group with YCD. The mean level of FSH was significantly higher in the group with YCD (28.45 ± 22.2 vs. 4.8 ± 3.17 and 10.83 ± 7.23 in YCD-negative patients with and without clinical pregnancy respectively).

Conclusion

YCD is frequent among NOA men and YCD screening before ART and patient counseling is thus strongly recommended.

Y-chromosome microdeletions in nonobstructive azoospermia and severe oligozoospermia

The aim of the present work was to present the outcomes of the patients with Y-chromosome microdeletions treated by intracytoplasmic sperm injection (ICSI), either using fresh (TESE) or frozen-thawed (TESE-C) testicular sperm and ejaculated sperm (EJAC). The originality of this work resides in the comparisons between the different types of Y-microdeletions (AZFa, AZFb, and AZFc) and treatments, with detailed demographic, stimulation, embryological, clinical, and newborn (NB) outcomes. Of 125 patients with Y-microdeletions, 33 patients presented severe oligozoospermia (18 performed ICSI with ejaculated sperm) and 92 secretory azoospermia (65 went for TESE with 40 having successful sperm retrieval and performed ICSI). There were 51 TESE treatment cycles and 43 TESE-C treatment cycles, with a birth of 19 NB (2 in AZFa/TESE-C, 12 in AZFc/TESE, and 5 in AZFc/TESE-C). Of the 29 EJAC cycles, there was a birth of 8 NB (in AZFc). In TESE and EJAC cycles, there were no significant differences in embryological and clinical parameters. In TESE-C cycles, there was a significant lower oocyte maturity rate, embryo cleavage rate and mean number of embryos transferred in AZFb, and a higher mean number of oocytes and lower fertilization rate in AZFc. In conclusion, although patients with AZFc microdeletions presented a high testicular sperm recovery rate and acceptable clinical outcomes, cases with AZFa and AZFb microdeletions presented a poor prognosis. Due to the reported heredity of microdeletions, patients should be informed about the infertile consequences on NB and the possibility of using preimplantation genetic diagnosis for female sex selection.

Basic and clinical genetic studies on male infertility in Iran during 2000-2016: A review

The male factor contributes to 50% of infertility. The cause of male infertility is idiopathic and could be congenital or acquired. Among different factors which are involved in idiopathic male infertility, genetic factors are the most prevalent causes of the disease. Considering, the high prevalence of male infertility in Iran and the importance of genetic factors in the accession of it, in this article we reviewed the various studies which have been published during the last 17 yr on the genetic basis of male infertility in Iran. To do this, the PubMed and Scientific information database (SID) were regarded for the most relevant papers published in the last 17 yr referring to the genetics of male factor infertility using the keywords ''genetics'', "cytogenetic", ''male infertility", and "Iranian population". Literatures showed that among the Iranian infertile men Yq microdeletion and chromosomal aberrations are two main factors that intervene in the genetics of male infertility. Also, protamine deficiency (especially P2) is shown to have an influence on fertilization rate and pregnancy outcomes. The highest rate of sperm DNA damages has been found among the asthenospermia patients. In several papers, the relation between other important factors such as single gene mutations and polymorphisms with male infertility has also been reported. Recognition of the genetic factors that influence the fertility of Iranian men will shed light on the creation of guidelines for the diagnosis, consultation, and treatment of the patients."

The frequencies of Y chromosome microdeletions in infertile males

OBJECTIVE

To determine the frequencies and the characteristics of Y chromosome microdeletions in infertile males.

MATERIAL AND METHODS

The records of 1616 infertile males were included in the study. The cases were divided into groups according to the infertility etiology and semen analysis. The frequencies and the characteristics of Y chromosome microdeletions were investigated in groups.

RESULTS

Y chromosome microdeletion was detected in 54 (3.3%) of 1616 cases. Microdeletions in the azoospermia factor (AZF) region were the most common (48.1%). When the cases were grouped according to causes of infertility that could be detected, no Y chromosome microdeletions were detected in some groups (cases with Klinefelter Syndrome, hypogonadotropic hypogonadism, congenital absence of vas deferens, and 47, XYY karyotype).

CONCLUSION

Y chromosome microdeletions were detected quite frequently in certain infertility subgroups. Therefore, detailed evaluation of an infertile man by physical examination, semen analysis, hormonal evaluations and when required, karyotype analysis may predict the patients for whom Y chromosome microdeletion analysis is necessary and also prevent cost increases.

Development and implementation of a novel panel consisting 20 markers for the detection of genetic causes of male infertility

Azoospermia factor (AZF) genes are involved in spermatogenesis. Deletions in the region of these genes have been recognised as a major genetic cause of infertility due to defects in spermatogenesis. Klinefelter syndrome (KS) is the other main cause of male infertility. This study was performed to establish a novel method for the detection of genetic causes of infertility in males and also to investigate the prevalence, extent and position of Y chromosome microdeletions in Iranian infertile men. We developed a newly designed panel of fluorescent multiplex-PCR method to amplify 20 markers (15 sequence-tagged sites (STSs) markers which are placed in the Y chromosome AZF region, 2 short tandem repeats (STRs) and 3 segmental duplications (SDs)). This multifunctional method is for the simultaneous detection of Y chromosome microdeletions and KS. Among 149 studied infertile men, one was detected to suffer from KS and seven (4.7%) were detected with the presence of one or more deleted STS loci. The main cause of infertility for the remaining patients would be nongenetic factors. This strategy is represented as a fast and accurate method to determine the frequencies of different AZF microdeletions which are suitable for use in clinical purposes.

Multiplex-Polymerase Chain Reaction for Detecting Microdeletions in The Azoospermia Factor Region of Y Chromosome in Iranian Couples with Non-Obstructive Infertility and Recurrent Pregnancy Loss

Background

Approximately 15% of couples are infertile with the male factor explaining approximately 50% of the cases. One of the main genetic factors playing a role in male infertility is Y chromosomal microdeletions within the proximal long arm of the Y chromosome (Yq11), named the azoospermia factor (AZF) region. Recent studies have shown there is a potential connection between deletions of the AZF region and recurrent pregnancy loss (RPL). The aim of this study is to examine this association by characterizing AZF microdeletions in two infertile groups: in men with non-obstructive infertility and in men with wives displaying RPL.

Materials and Methods

In this is a case-control study, genomic DNA was extracted from 80 male samples including 40 non-obstructive infertile men, 20 males from couples with RPL and 20 fertile males as controls. Multiplex polymerase chain reaction was used to amplify 19 sequence tagged sites (STS) to detect AZF microdeletions. Differences between the case and control groups were evaluated by two-tailed unpaired t test. P<0.05 were considered statistically significant.

Results

Only one subject was detected to have Y chromosome microdeletions in SY254, SY157 and SY255 among the 40 men with non-obstructive infertility. No microdeletion was detected in the males with wives displaying RPL and in 20 control males. Y chromosome microdeletion was neither significantly associated with non-obstructive infertility (P=0.48) nor with recurrent pregnancy loss.

Conclusion

Performing Testing for Y chromosome microdeletions in men with non-obstructive infertility and couples with RPL remains inconclusive in this study.

Molecular‑cytogenetic study of de novo mosaic karyotype 45,X/46,X,i(Yq)/46,X,idic(Yq) in an azoospermic male: Case report and literature review

The present study describes a 36‑year‑old male with the 45,X/46,X,i(Yq)/46,X,idic(Yq) karyotype, who suffered from azoospermia attributed to maturation arrest of the primary spermatocyte. To the best of our knowledge, this rare karyotype has not yet been reported in the literature. The results of detailed molecular‑cytogenetic studies of isodicentric (idic)Y chromosomes and isochromosome (iso)Y, which are identified in patient with complex mosaic karyotypes, are presented. The presence of mosaicism of the three cell lines 45,X, 46,X,i(Yq) and 46,X,idic(Yq) may be a contributing factor for spermatogenic failure, in addition to the instability of iso/idic Y chromosomes to pass the spermatogenesis process. Possible mechanisms of the formation of the mosaic karyotype and karyotype‑phenotype correlations are discussed. The current study highlights that routine karyotype analysis and fluorescent in situ hybridization‑based technology are more useful in detecting mosaic chromosomal abnormality, predicting the clinical features of patients during genetic counseling and improving artificial reproductive technologies.

The Prevalence of Y Chromosome Microdeletions in Iranian Infertile Men with Azoospermia and Severe Oligospermia

OBJECTIVE

Microdeletions of the Y chromosome long arm are the most common molecular genetic causes of severe infertility in men. They affect three regions including azoospermia factors (AZFa, AZFb and AZFc), which contain various genes involved in spermatogenesis. The aim of the present study was to reveal the patterns of Y chromosome microdeletions in Iranian infertile men referred to Royan Institute with azoospermia/ severe oligospermia.

MATERIALS AND METHODS

Through a cross-sectional study, 1885 infertile men referred to Royan Institute with azoospermia/severe oligospermia were examined for Y chromosome microdeletions from March 2012 to March 2014. We determined microdeletions of the Y chromosome in the AZFa, AZFb and AZFc regions using multiplex Polymerase chain reaction and six different Sequence-Tagged Site (STS) markers.

RESULTS

Among the 1885 infertile men, we determined 99 cases of Y chromosome microdeletions (5.2%). Among 99 cases, AZFc microdeletions were found in 70 cases (70.7%); AZFb microdeletions in 5 cases (5%); and AZFa microdeletions in only 3 cases (3%). AZFbc microdeletions were detected in 18 cases (18.1%) and AZFabc microdeletions in 3 cases (3%).

CONCLUSION

Based on these data, our results are in agreement with similar studies from other regions of the world as well as two other recent studies from Iran which have mostly reported a frequency of less than 10% for Y chromosome microdeletions.

Single nucleotide polymorphisms of USP26 in azoospermic men

Some studies have focused on the association between male infertility and single nucleotide polymorphisms (SNPs) in the ubiquitin-specific protease 26 (USP26) gene, but the results are controversial. In this case-control study including both normozoospermic men and patients with nonobstructive azoospermia, we analyzed both the entire coding region and 5' and 3' untranslated regions of USP26 in order to identify genetic variants in this gene to investigate the role of USP26 on spermatogenesis. We reported variations in the USP26 gene sequence in 82% of azoospermic and in 50% normospermic men. The synonymous variation c.576G>A has a frequency significantly different in the azoospermic (60.2%) and normozoospermic (23.6%) groups, while the frequencies in the two groups of both c.1090C>T and c.1737G>A missense mutations did not reach statistical significance. A cluster mutation (c.371insACA, c.494T>C) was detected in 2 normozoospermic men (2.7%). In the 5'UTR we identified the -33C>T variation both in azoospermic (3.8%) and in normozoospermic (2.7%) men. In a normozoospermic man we detected the nonsense mutation c.882C>A, never reported to date. According to our results, we suggest that only the variation c.576G>A has a frequency significantly different in azoospermic compared to normozoospermic men. Moreover, the identification in a normozoospermic man of a nonsense mutation (c.882C>A) which causes the production of a truncated protein, suggests a marginal role of USP26 in male spermatogenesis. Additional studies may be useful as we cannot exclude that the other SNPs may represent risk factors for male fertility acting by an oligogenic/polygenic mechanism.

Frequency of Y Chromosome Microdeletions Among Iranian Infertile Men with Azoospermia and Severe Oligozoospermia: A Meta-analysis

BACKGROUND

While multiple factors can contribute to male infertility, genetic factors, such as chromosomal disorders or Y-chromosome microdeletion, are responsible for about 10% of male infertility. Considering the role of Y-chromosome micro-deletions in men with oligozoospermia who volunteer for in vitro fertilization (IVF), the prevalence of such microdeletions in each particular community needs to be exactly determined. Hence, the present study attempted to analyze the available literature on the frequency of chromosome microdeletion among Iranian infertile men.

METHODS

In the first stage, a systematic search was performed on international and Iranian databases including PubMed, Scopus, Web of Science, IranMedex, MEDLIB, and Scientific Information Database in order to extract all relevant studies published until December 1, 2014.

RESULTS

According to the literature review and meta-analysis process, Y chromosome microdeletions were present in about 12.1% (95% CI, 6.5-21.5) of Iranian infertile men with azoospermia and severe oligozoospermia.

CONCLUSION

Because of the presence of Y-chromosome microdeletion in at least 12% of Iranian infertile men, it is necessary all the IVF centers, implement this Y-chromosome microdeletion screening tests in the work-up of male infertility.

Y chromosome azoospermia factor region microdeletions and transmission characteristics in azoospermic and severe oligozoospermic patients

Spermatogenesis is an essential reproductive process that is regulated by many Y chromosome specific genes. Most of these genes are located in a specific region known as the azoospermia factor region (AZF) in the long arm of the human Y chromosome. AZF microdeletions are recognized as the most frequent structural chromosomal abnormalities and are the major cause of male infertility. Assisted reproductive techniques (ART) such as intra-cytoplasmic sperm injection (ICSI) and testicular sperm extraction (TESE) can overcome natural fertilization barriers and help a proportion of infertile couples produce children; however, these techniques increase the transmission risk of genetic defects. AZF microdeletions and their associated phenotypes in infertile males have been extensively studied, and different AZF microdeletion types have been identified by sequence-tagged site polymerase chain reaction (STS-PCR), suspension array technology (SAT) and array-comparative genomic hybridization (aCGH); however, each of these approaches has limitations that need to be overcome. Even though the transmission of AZF microdeletions has been reported worldwide, arguments correlating ART and the incidence of AZF microdeletions and explaining the occurrence of de novo deletions and expansion have not been resolved. Using the newest findings in the field, this review presents a systematic update concerning progress in understanding the functions of AZF regions and their associated genes, AZF microdeletions and their phenotypes and novel approaches for screening AZF microdeletions. Moreover, the transmission characteristics of AZF microdeletions and the future direction of research in the field will be specifically discussed.

A Rare De novo Complex Chromosomal Rearrangement (CCR) Involving Four Chromosomes in An Oligo-asthenosperm Infertile Man

Complex chromosomal rearrangements (CCRs) are rare events involving more than two chromosomes and over two breakpoints. They are usually associated with infertility or sub fertility in male carriers. Here we report a novel case of a CCR in a 30-year-old oligoasthenosperm man with a history of varicocelectomy, normal testes size and normal endocrinology profile referred for chromosome analysis to the Genetics unit of Royan Reproductive Biomedicine Research Center. Chromosomal analysis was performed using peripheral blood lymphocyte cultures and analyzed by GTG banding. Additional tests such as C-banding and multicolor fluorescence in situ hybridization (FISH) procedure for each of the involved chromosomes were performed to determine the patterns of the segregations. Y chromosome microdeletions in the azoospermia factor (AZF) region were analyzed with multiplex polymerase chain reaction. To identify the history and origin of this CCR, all the family members were analyzed. No micro deletion in Y chromosome was detected. The same de novo reciprocal exchange was also found in his monozygous twin brother. The other siblings and parents were normal. CCRs are associated with male infertility as a result of spermatogenic disruption due to complex meiotic configurations and the production of chromosomally abnormal sperms. These chromosomal rearrangements might have an influence on decreasing the number of sperms.

Human spermatozoa: revelations on the road to conception

Human spermatozoa are highly complex specialized cells designed to survive a long and perilous journey from the site of insemination to the upper reaches of the female reproductive tract where fertilization occurs. During this journey, these cells have to run the gauntlet laid down by the female immune system and time their physiological maturation so that as soon as an egg appears in the Fallopian tube, they are equipped to recognize this cell and participate in a remarkable cascade of cellular interactions culminating in fertilization. Despite their high level of specialization, human spermatozoa are notoriously inadequate and appear to be major contributors to the poor fertility that characterizes our species. Defective spermatozoa are also known to have a major impact on the progress of pregnancy and the health trajectory of the offspring, resulting in paternally mediated increases in miscarriage rate and a range of diseases in the progeny, including dominant genetic diseases and cancer. The causes of defective sperm function are complex and involve both genetic and environmental impacts, as well as paternal age. Where genetic factors are involved, there is a concern that the widespread use of assisted conception technologies will serve to enhance the retention of poor fertility genes in the population such that the more we use assisted reproductive technologies in one generation the more we shall need them in the next. These observations may have important implications for the health and well-being of children and for the provision of reproductive healthcare services for future generations.

Ubiquitin-specific protease (USP26) gene alterations associated with male infertility and recurrent pregnancy loss (RPL) in Iranian infertile patients

BACKGROUND AND PURPOSE

The human X chromosome is enriched with testis-specific genes that may be crucial for male fertility. Mutations in USP26 gene have been proposed to be associated with male infertility. Moreover, the importance of the ubiquitin pathway during different stages of mammalian fertilization and even embryo development has been addressed. Some mutations and haplotypes on this gene have been proposed to be associated with male infertility. In this study, five different mutations on USP26 were investigated: 1737 G > A, 1090 C > T, 370-371ins ACA, 494 T > C and 1423 C > T.

METHODS

The study included 166 infertile men with non-obstructive azoospermia, 72 male partners of couples who had previously experienced ≥3 clinical first trimester spontaneous abortions and 60 fertile men. Besides family history of reproduction, hormonal evaluation and semen analysis were performed. DNA was extracted from blood samples. PCR-SSCP, PCR-RFLP and PCR Product Cloning methods were used and resumed by sequencing to insure about the mutations. Moreover, USP26 gene expression was studied by Real-Time PCR after RNA extraction followed by cDNA synthesis from 24 testis biopsies in obstructive and non-obstructive azoospermia patients.

RESULTS

The results indicate that there is a haplotype between three observed mutations in Iranian population include: 370-371insACA, 1423C > T and 494 T > C. This haplotype was seen in control group as well. Surprisingly, total frequency of mutations in men with history of idiopathic RPL and azoospermic cases were significantly higher than that of in control groups (p < 0.05). Serum testosterone concentrations and testicular volume did not differ in the mutation positive group compared with the non-mutation group. About the USP26 gene expression, there is a significant difference between the expression levels of obstructive azoospermia, complete maturation arrest samples and SCO samples (P < 0.05).

CONCLUSIONS

According to our results, the USP26 gene may play an important role in male reproduction. The alterations of this gene may be involved in male infertility and RPL in Iranian population and may negatively affect testicular function.

Analysis of Y chromosome microdeletion in 1738 infertile men from northeastern China

OBJECTIVE

To determine the frequencies and the characteristics of Y chromosome microdeletion in infertile men from northeastern China to perform appropriate therapeutic choices.

MATERIALS AND METHODS

The study included 1738 infertile men. Sperm concentration was measured according to standard methods and karyotype analysis was performed on peripheral blood lymphocytes with standard G-banding. Multiplex polymerase chain reaction amplification using 9 specific sequence-tagged sites were selected to detect Y chromosome microdeletions.

RESULTS

The data showed that the frequency of Y chromosome microdeletion was 8.57%. The most common microdeletion, among the azoospermia factor (AZF) regions, was detected in the AZFc region, followed by AZFb+c, AZFb, AZFa+b+c, AZFa, and AZFa+c. One-hundred seven patients with Y chromosome microdeletion developed azoospermia, 39 developed severe oligozoospermia (sperm concentration ≤5 × 10(6)/mL), and 3 developed moderate oligozoospermia (sperm concentration >5 × 10(6)/mL and ≤10 × 10(6)/mL). Karyotype analysis was available for 130 patients with Y chromosome microdeletion and abnormal karyotypes were found in 19 patients (14.6%). The most frequent abnormal karyotype was 46,X,Yqh-(n = 7).

CONCLUSION

In northeastern China, Y chromosome microdeletion diagnosis should be performed before the use of intracytoplasmic sperm injection in infertile men with sperm count ≤10 × 10(6)/mL, especially in men with azoospermia.

Association between Y-chromosome AZFc region micro-deletions with recurrent miscarriage

BACKGROUND

In human, about 25% of implanted embryos are losing 1-2 week following attachment to the uterus. A subset of this population will have three or more consecutive miscarriages which define as repeated pregnancy loss (RPL). Introducing the assisted reproductive technologies (ARTS) made a chance for infertile couples to solve their childless problem.

OBJECTIVE

This study was conducted to evaluate the incidence of Y-chromosome AZF region's micro-deletions in male partners of couples with recurrent miscarriage (RM).

MATERIALS AND METHODS

Thirty male partner of couples with RM and thirty infertile males, who referred to the Yazd Research and Clinical Center for Infertility were recruited to this study. In addition, 30 healthy men were screened as a control group from the same center. After DNA extraction using salting out method, the multiplex-PCR was done for amplifying 8 known STSs proximal to the AZF region of the Y-chromosome. The results were compared between the groups using Fisher's exact t-test and p<0.05 was considered statistically significant.

RESULTS

Of the 30 infertile males, 5 (16.6%) cases were associated with the AZF region micro-deletions of DYF87S, DYF84S1, DYF83S1 and DYF51S1, STSs. But in the fertile and RM male groups was found no deletions similar to those, of the infertile males (p=1.0). Instead 4 (13.3%) cases of the RM group males had different micro-deletions included DYS220 (AZFb, sY129), DYS262, DYF8551, and DYF8651, STSs. The AZFc locus of Y-chromosome micro-deletions have a significant role in RM (p=0.045).

CONCLUSION

It seems that the Y-chromosome AZF region's micro-deletions are associated with RM, and we recommend adding this AZF region STSs into infertility analyzing panels.