AZF microdeletions and partial deletions of AZFc region on the Y chromosome in Moroccan men

Y-chromosome haplogroups and Azoospermia Factor (AZF) analysis in Tunisian infertile male

The aim of the present study was to clarify the implication of Y chromosome genetic variations and haplogroups in Tunisian infertile men. A total of 27 Y-chromosomal binary markers partial microdeletions (gr/gr, b1/b3 and b2/b3) and copy number variation of DAZ and CDY genes in the AZFc region were analysed in 131 Tunisian infertile men with spermatogenic failure and severe reduced sperm concentrations and in 85 normospermic men as controls. Eleven different haplogroups in the overall population study (E3b2; J1J*, E1, E3b*, F, G, K, P/Q, R*, R1* and R1a1) were found. Interestingly, the J1J* haplogroup was significantly more frequent in azoo/oligospermic patients than in normospermic men (35.1% and 22.3%, respectively (p value = 0.04)). Results showed also that patients without DAZ/CDY1 copies loss and without partial microdeletions belonged to the R1 haplogroup. The relative high frequencies of two haplogroups, E3b2 (35.1%) and J (30%) was confirmed in Tunisia. We reported in the present study and for the first time, that J1J* haplogroup may confer a risk factor for infertility in the Tunisian population and we suggested that R1 haplogroup may ensure certain stability to Y-chromosome in Tunisian men.

Detection of AZF microdeletions and reproductive hormonal profile analysis of infertile sudanese men pursuing assisted reproductive approaches

Background

Male factor is the major contributor in roughly half of infertility cases. Genetic factors account for 10–15% of male infertility. Microdeletions of azoospermia factors (AZF) on the Yq region are the second most frequent spermatogenesis disorder among infertile men after Klinefelter syndrome. We detected in our previous study a frequency of 37.5% AZF microdeletions which investigated mainly the AZFb and AZFc. We attempted in this study for the first time to evaluate the frequencies of all AZF sub-regions microdeletions and to analyze reproductive hormonal profiles in idiopathic cases of azoospermic and oligozoospermic men from Sudan.

Methods

A group of 51 medically fit infertile men were subjected to semen analysis. Four couples have participated in this study as a control group. Semen analysis was performed according to WHO criteria by professionals at Elsir Abu-Elhassan Fertility Centre where samples have been collected. We detected 12 STSs markers of Y chromosome AZF microdeletions using a multiplex polymerase chain reaction. Analysis of reproductive hormone levels including Follicle Stimulating, Luteinizing, and Prolactin hormones was performed using ELISA. Comparisons between outcome groups were performed using Student’s t-test Chi-square test or Fisher’s exact test.

Results

AZF microdeletion was identified in 16 out of 25 Azoospermic and 14 out of 26 of the Oligozoospermic. Microdeletion in the AZFa region was the most frequent among the 30 patients (N = 11) followed by AZFc, AZFd (N = 4 for each) and AZFb (N = 3). Among the Oligozoospermic participants, the most frequent deletions detected were in the AZFa region (N = 10 out of 14) and was significantly associated with Oligozoospermic phenotype, Fisher's Exact Test (2-sided) p = 0.009. Among the Azoospermic patients, the deletion of the AZFc region was the most frequent (N = 9 out of 16) and was significantly associated with Azoospermia phenotype Fisher's Exact Test p = 0.026. There was a significant difference in Y chromosome microdeletion frequency between the two groups. The hormonal analysis showed that the mean levels of PRL, LH, and FSH in Azoospermic patients were slightly higher than those in oligozoospermic. A weak negative correlation between prolactin higher level and Azoospermic patients was detected. (AZFa r = 0.665 and 0.602, p = 0.000 and 0.0004, AZFb r = 0.636 and 0.409, p = 0.000 and 0.025, and AZFd r = 0.398 and 0.442, p = 0.029 and 0.015). The correlation was positive for AZFa and negative for AZFb and AZFd.

Conclusions

We concluded in this study that the incidences of microdeletions of the Y chromosome confined to AZF a, b, c and d regions is 58.8% in infertile subjects with 31.4% were Azoospermic and 27.5% were Oligozoospermic. This might provide a piece of evidence that these specified regions of the Y chromosome are essential for controlling spermatogenesis. These findings will be useful for genetic counseling within infertility clinics in Sudan and to adopt appropriate methods for assisted reproduction.

Evaluation of Y chromosome microdeletions and chromosomal anomalies in infertile men

OBJECTIVES

Chromosome anomalies and Y chromosome microdeletions are one of the reasons that can be seen in infertile patients and affect fertility. In this study, it was aimed to determine the frequencies of chromosomal anomalies and Y chromosome microdeletions in primary infertile male patients.

METHODS

We included 374 patients with primary infertility in this study. Cytogenetic analysis was performed with the GTG banding technique by using trypsin and Giemsa stain. Y microdeletion analysis was studied by multiplex polymerase chain reaction using 28 Y chromosome-specific sequence-tagged sites.

RESULTS

Chromosomal irregularities were detected in 27 (7.22%) of infertile cases. It was observed that 7 (25.92%) of chromosomal irregularities detected in cases were in autosomal and 20 (%74.08) were in gonosomal chromosomes. The incidence of Y chromosome microdeletion was 1.07% (4/374) and the microdeletions were observed in AZFb, AZFc and AZFd regions. AZFc + AZFd deletion was detected in three patients (0.81%) and AZFb + AZFc + AZFd deletion in one patient (0.26%).

CONCLUSIONS

In conclusion, gonosomal chromosome irregularity was higher than autosomal chromosome irregularity in infertile men. The frequency of Y microdeletion has different rates according to some factors such as ethnic differences of patients, patient selection criteria, differences in the number of cases, and methodological aspects.

Chromosomal abnormalities and Y chromosome microdeletions in infertile men with azoospermia and oligozoospermia in Eastern China

Objective

The objective was to investigate the frequency and type of chromosomal abnormalities and Y chromosome microdeletions in infertile men with azoospermia and oligozoospermia to ensure appropriate genetic counseling before assisted reproduction in Eastern China.

Methods

A total of 201 infertile men (148 with azoospermia and 53 with oligozoospermia) were enrolled. Real-time PCR using six Y-specific sequence-tagged sites of the azoospermia factor (AZF) region was performed to screen for microdeletions. Karyotype analyses were performed on peripheral blood lymphocytes with standard G-banding.

Results

Out of 201 infertile patients, 22 (10.95%) had Y microdeletions [17/148 (11.49%) men with azoospermia and 5/53 (9.43%) men with oligozoospermia]. The most frequent microdeletions were in the AZFc region, followed by the AZFa+b + c, AZFb+c, AZFa, and AZFb regions. Chromosomal abnormalities were detected in 18.91% (38/201) of patients, 34 of which were sex chromosome abnormalities (16.92%) and 4 of which were autosomal abnormalities (1.99%). Chromosomal abnormalities were more prevalent in men with azoospermia (22.97%) than in those with oligozoospermia (7.55%).

Conclusions

We detected a high incidence of chromosomal abnormalities and Y chromosomal microdeletions in infertile Chinese men with azoospermia and oligozoospermia. These findings suggest the need for genetic testing before the use of assisted reproduction techniques.

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.

High frequencies of Non Allelic Homologous Recombination (NAHR) events at the AZF loci and male infertility risk in Indian men

Deletions in the AZoospermia Factor (AZF) regions (spermatogenesis loci) on the human Y chromosome are reported as one of the most common causes of severe testiculopathy and spermatogenic defects leading to male infertility, yet not much data is available for Indian infertile men. Therefore, we screened for AZF region deletions in 973 infertile men consisting of 771 azoospermia, 105 oligozoospermia and 97 oligoteratozoospermia cases, along with 587 fertile normozoospermic men. The deletion screening was carried out using AZF-specific markers: STSs (Sequence Tagged Sites), SNVs (Single Nucleotide Variations), PCR-RFLP (Polymerase Chain Reaction - Restriction Fragment Length Polymorphism) analysis of STS amplicons, DNA sequencing and Southern hybridization techniques. Our study revealed deletion events in a total of 29.4% of infertile Indian men. Of these, non-allelic homologous recombination (NAHR) events accounted for 25.8%, which included 3.5% AZFb deletions, 2.3% AZFbc deletions, 6.9% complete AZFc deletions, and 13.1% partial AZFc deletions. We observed 3.2% AZFa deletions and a rare long AZFabc region deletion in 0.5% azoospermic men. This study illustrates how the ethnicity, endogamy and long-time geographical isolation of Indian populations might have played a major role in the high frequencies of deletion events.

Mediterranean Y-chromosome 2.0-why the Y in the Mediterranean is still relevant in the postgenomic era

CONTEXT

Due to its unique paternal inheritance, the Y-chromosome has been a highly popular marker among population geneticists for over two decades. Recently, the advent of cost-effective genome-wide methods has unlocked information-rich autosomal genomic data, paving the way to the postgenomic era. This seems to have announced the decreasing popularity of investigating Y-chromosome variation, which provides only the paternal perspective of human ancestries and is strongly influenced by genetic drift and social behaviour.

OBJECTIVE

For this special issue on population genetics of the Mediterranean, the aim was to demonstrate that the Y-chromosome still provides important insights in the postgenomic era and in a time when ancient genomes are becoming exponentially available.

METHODS

A systematic literature search on Y-chromosomal studies in the Mediterranean was performed.

RESULTS

Several applications of Y-chromosomal analysis with future opportunities are formulated and illustrated with studies on Mediterranean populations.

CONCLUSIONS

There will be no reduced interest in Y-chromosomal studies going from reconstruction of male-specific demographic events to ancient DNA applications, surname history and population-wide estimations of extra-pair paternity rates. Moreover, more initiatives are required to collect population genetic data of Y-chromosomal markers for forensic research, and to include Y-chromosomal data in GWAS investigations and studies on male infertility.

Partial Deletions of Y-Chromosome in Infertile Men with Non-obstructive Azoospermia and Oligoasthenoteratozoospermia in a Turkish Population

Many genetic alterations have been identified to aid in understanding the genetic basis of male infertility, however, the cause of 30% of male infertility remains unknown. Some studies indicated that subdeletions of Y chromosome may be a reason for male infertility caused by testicular failure. In this regard, we aimed to investigate frequency of AZFc region subdeletions and their clinical effects in patients with idiopathic infertility. A total of 333 male infertile patients with non-obstructive azoospermia (NOA) or oligoasthenoteratozoospermia (OAT), and 87 normozoospermic controls were screened to detect gr/gr, b1/b3 and b2/b3 subdeletions. We recorded higher gr/gr deletion frequency in normozoospermic controls compared NAO and OAT groups (p=0.026). There were no significant differences in b2/b3 subdeletion rates among groups (p=0.437). In the OAT group, follicle-stimulating hormone levels of cases with b2/b3 deletion were statistically lower than cases without b2/b3 deletion (p=0.047). No statistical correlations were indicated among subdeletions, sperm count and assisted reproductive technology (ART) outcomes. These data demonstrate that gr/gr and b2/b3 subdeletions may not play a significant role in the etiopathogenesis of male infertility and ART outcomes in the studied population.

Y chromosome b2/b3 deletions and male infertility: A comprehensive meta-analysis, trial sequential analysis and systematic review

The correlation of Y-chromosome b2/b3 partial deletions with spermatogenic failure remains dubious. We undertook a systematic review of the literature followed by meta-analyses and trial sequential analyses in order to compare the frequency of b2/b3 deletions between oligo/azoospermic infertile and normozoospermicmen. Out of twenty-four studies reviewed for meta-analysis, twenty reported no correlation between this deletion and male infertility and two studies each reported a direct and inverse correlation. In the collective analysis, 241 out of 8892 (2.71%) oligo/azoospermic individuals and 118 out of 5842 (2.02%) normozoospermic controls had a b2/b3 deletion, suggesting a relatively higher frequency of deletions in the cases. Eventually, meta-analysis showed a significant correlation between b2/b3 deletions and the risk of spermatogenic loss/infertility (Fixed model: OR=1.313, 95% CI=1.04-1.65, p=0.02; Random model: OR=1.315, 95% CI=1.02-1.70, p=0.037). Further meta-analysis on studies grouped by ethnicity and geographic regions showed that the b2/b3 deletions are significantly associated with spermatogenic loss/infertility in Mongolians, Nigro-Caucasians, East Asians and Africans, but not in Caucasians, Europeans, South Asians and Dravidians. In summary, the Y-chromosome b2/b3 deletions increase infertility risk; however, it may be significant only in the Mongolian populations and the East Asian region.

Gr/gr deletions on Y-chromosome correlate with male infertility: an original study, meta-analyses, and trial sequential analyses

We analyzed the AZFc region of the Y-chromosome for complete (b2/b4) and distinct partial deletions (gr/gr, b1/b3, b2/b3) in 822 infertile and 225 proven fertile men. We observed complete AZFc deletions in 0.97% and partial deletions in 6.20% of the cases. Among partial deletions, the frequency of gr/gr deletions was the highest (5.84%). The comparison of partial deletion data between cases and controls suggested a significant association of the gr/gr deletions with infertility (P = 0.0004); however, the other partial deletions did not correlate with infertility. In cohort analysis, men with gr/gr deletions had a relatively poor sperm count (54.20 ± 57.45 million/ml) in comparison to those without deletions (72.49 ± 60.06), though the difference was not statistically significant (p = 0.071). Meta-analysis also suggested that gr/gr deletions are significantly associated with male infertility risk (OR = 1.821, 95% CI = 1.39–2.37, p = 0.000). We also performed trial sequential analyses that strengthened the evidence for an overall significant association of gr/gr deletions with the risk of male infertility. Another meta-analysis suggested a significant association of the gr/gr deletions with low sperm count. In conclusion, the gr/gr deletions show a strong correlation with male infertility risk and low sperm count, particularly in the Caucasian populations.

Chromosomal abnormalities and Y chromosome microdeletions in infertile men from Morocco

Background

Male infertility is responsible for 50 % of infertile couples. Thirty percent of male infertility is due to cytogenetic and genetic abnormalities. In Arab and North African populations, several studies have shown the association of these chromosomal abnormalities with male infertility. Our objective is to evaluate the frequency of chromosomal abnormalities and Y chromosome microdeletions in infertile men from Morocco.

Methods

A total of 573 Moroccan infertile men (444 azoospermic and 129 oligozoospermic men) referred for cytogenetic analysis to the Department of Cytogenetics of the Pasteur Institute of Morocco, were screened for the presence of chromosomal abnormalities and Y chromosome microdeletions.

Results

Chromosomal abnormalities accounted for approximately 10.5 % (60/573). Fifty six cases among them have sex chromosome abnormalities (93.34 %), including Klinefelter’s syndrome in 41 patients (68.34 %). Autosomal chromosome abnormalities (6.66 %) were observed in 4 patients. Chromosomal abnormalities were more prevalent in azoospermic men (13.06 %) than in oligospermic men (1.55 %). Y microdeletions were detected in 16 of 85 patients (AZFc: 14.12 %, AZFbc: 4.70 %), most of them where azoospermic men with no chromosomal abnormality.

Conclusions

These results highlighted the need for efficient molecular genetic testing in male infertility diagnosis. In addition, a genetic screening should be performed in infertile men before starting assisted reproductive treatments.

Impact of partial DAZ1/2 deletion and partial DAZ3/4 deletion on male infertility

This study aims to investigate the effect of the partial DAZ1/2 deletion and partial DAZ3/4 deletion on male infertility through a comprehensive literature search. All case-control studies related to partial DAZ1/2 and DAZ3/4 deletions and male infertility risk were included in our study. Odd ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the association and its precision, respectively. Eleven partial DAZ1/2 deletion and nine partial DAZ3/4 deletion studies were included. Partial DAZ1/2 deletion was significantly associated with male infertility risk in the overall analysis (ORs=2.58, 95%CI: 1.60-4.18, I(2)=62.1%). Moreover, in the subgroup analysis stratified by ethnicity, partial DAZ1/2 deletion was significantly associated with male infertility risk in the East Asian populations under the random effect model (ORs=2.96, 95%CI: 1.87-4.71, I(2)=51.3%). Meanwhile, the analysis suggested that partial DAZ3/4 deletion was not associated with male infertility risk in East-Asian ethnicity (ORs=1.02, 95%CI: 0.54-1.92, I(2)=71.3%), but not in Non-East Asian under the random effect model (ORs=3.56, 95%CI: 1.13-11.23, I(2)=0.0%,). More interestingly, partial DAZ1/2 deletion was associated with azoospermia (ORs=2.63, 95%CI: 1.19-5.81, I(2)=64.7%) and oligozoospermia (ORs=2.53, 95%CI: 1.40-4.57, I(2)=51.8%), but partial DAZ3/4 deletion was not associated with azoospermia (ORs=0.71, 95%CI: 0.23-2.22, I(2)=71.7%,) and oligozoospermia (ORs=1.21, 95%CI: 0.65-2.24, I(2)=55.5%). In our meta-analysis, partial DAZ1/2 deletion is a risk factor for male infertility and different ethnicities have different influences, whereas partial DAZ3/4 deletion has no effect on fertility but partial DAZ3/4 deletion might have an impact on Non-East Asian male.

Susceptibility of gr/gr rearrangements to azoospermia or oligozoospermia is dependent on DAZ and CDY1 gene copy deletions

PURPOSE

The purpose of this study was to determine the association of AZFc subdeletions (gr/gr, b1/b3 and b2/b3) and deletion of DAZ and CDY1 gene copies with male infertility

METHODS

Three hundred twelve controls, 172 azoospermic and 343 oligozoospermic subjects were subjected to AZFc subdeletion typing by STS PCR. Deletion of DAZ and CDY1 gene copies was done using sequence family variant analysis. Sperm concentration and motility were compared between men with and without AZFc subdeletions. Effect of the AZFc subdeletions on ICSI outcome was evaluated.

RESULTS

Amongst the three AZFc subdeletions, the frequency of gr/gr was higher in oligozoospermic (10.5 %) and azoospermic (11.6 %) men as compared to controls (5.1 %). In men with AZFc subdeltions, loss of two DAZ and one CDY1 gene copy made them highly susceptible to azoospermia and severe oligozoospermia with OR of 29.7 and 26, respectively. These subdeletions had no effect on ICSI outcome, albeit there were an increased number of poor quality embryos in AZFc subdeleted group.

CONCLUSION

AZFc subdeletions are a major risk factor for male infertility in the Indian population. In the subjects with AZFc subdeletions, the deletion of DAZ and CDY1 gene copies increases its susceptibility to azoospermia or severe oligozoospermia. Since these deletions can be vertically transmitted to the future male offspring by ICSI, it will be essential to counsel the couples for the transmission of the genetic defect in the male offspring born after assisted reproduction and the risk of perpetuating infertility in future generation.

Screening for AZFc partial deletions in Dravidian men with nonobstructive azoospermia and oligozoospermia

CONTEXT

Dravidians are the predominant population residing in South India with a diverse genetic structure. Considering various genetic discoveries taking place today, it is evident that deletions in the AZFc region are the most common cause of severe spermatogenic failure (SSF) in various populations studied. However, it is significant to note that there is a paucity of scientific literature on AZFc subdeletion screening among the Dravidian population.

OBJECTIVE

To investigate the prevalence and association of AZFc subdeletion patterns among Dravidian men with nonobstructive azoospermia (NOA) and oligozoospermia.

METHODS

A population of 354 subjects, including 120 patients with NOA, 109 with oligozoospermia, and 125 normal male controls, were screened using locus-specific sequence tag site markers.

RESULTS

We found 21 (9.17%) patients with classical AZF deletion, while no deletions were observed in controls. After excluding the samples with AZF deletions, the remaining 208 infertile and 125 control samples were screened for partial AZFc deletions using a standardized multiplex polymerase chain reaction and on analysis revealed that 13 (6.25%) of the infertile samples possessed gr/gr subdeletions and 15 (7.21%) of the infertile samples possessed b2/b3 subdeletions. Six (4.8%) of the normal samples were found to carry gr/gr subdeletions and two (1.6%) had b2/b3 deletions. The b1/b3 deletion was not observed in any of the patient and control samples screened.

CONCLUSION

Our finding shows that there is a strong association between b2/b3 subdeletion and SSF in the Dravidian population (odds ratio, 4.78; 95% confidence interval 1.07-21.26) (p=0.018). Further studies, including gene copy typing for DAZ and CDY genes and a comprehensive haplogrouping analysis, are recommended in a large and well-selected patient group to elude the genetic mechanism behind this association.

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.

Association of azoospermia factor region deletions in infertile male subjects among Malaysians

Azoospermia factor region (AZF) deletions (AZFa, AZFb, AZFc and AZFd) in the Y chromosome were analysed in male infertility subjects in various populations with conflicting results. This study comprised of 54 infertile males and 63 fertile controls, and the frequency of AZFa, AZFb, AZFc and AZFd deletions were determined using conventional polymerase chain reaction (PCR) as well as real-time PCR-high resolution melting analysis-based methods. The results of this study showed that, three of 54 cases (5.55%) had AZF (a, b and c) deletions (two had AZFc and one had AZFa deletions). Four cases were found to have AZFd deletions (7.4%) with two of them being associated with AZFc deletions (P = 0.028). The frequency of AZF (a, b and c) deletions in Malaysian infertile male subjects was found to be comparable with other populations. AZFd deletions were found to be significant (P < 0.05) in male infertility and it may be associated with other types of AZF deletions.

Clinical relevance of Y-linked CNV screening in male infertility: new insights based on the 8-year experience of a diagnostic genetic laboratory

AZF microdeletion screening is routinely performed in the diagnostic work-up for male infertility; however, some issues remain debated. In this study, we provide insights into the sperm concentration cutoff value for routine testing, the predictive value of AZFc deletion for testicular sperm retrieval and the Y-background contribution to the interpopulation variability of deletion frequencies. In the Spanish population, partial AZFc rearrangements have been poorly explored and no data exist on partial duplications. In our study, 27/806 (3.3%) patients carried complete AZF deletions. All were azoo/cryptozoospermic, except for one whose sperm concentration was 2 × 10(6)/ml. In AZFc-deleted men, we observed a lower sperm recovery rate upon conventional TESE (9.1%) compared with the literature (60-80% with microTESE). Haplogroup E was the most represented among non-Spanish and hgr P among Spanish AZF deletion carriers. The analysis of AZFc partial rearrangements included 330 idiopathic infertile patients and 385 controls of Spanish origin. Gr/gr deletion, but not AZFc partial duplications, was significantly associated with spermatogenic impairment. Our data integrated with the literature suggest that: (1) routine AZF microdeletion testing could eventually include only men with ≤2 × 10(6)/ml; (2) classical TESE is associated with low sperm recovery rate in azoospermic AZFc-deleted men, and therefore microTESE should be preferred; (3) Y background could partially explain the differences in deletion frequencies among populations. Finally, our data on gr/gr deletion further support the inclusion of this genetic test in the work-up of infertile men, whereas partial AZFc duplications do not represent a risk for spermatogenic failure in the Spanish population.

High prevalence of genetic abnormalities in Middle Eastern patients with idiopathic non-obstructive azoospermia

INTRODUCTION

Our objective is to detect the frequency and types of major genetic abnormalities of idiopathic non-obstructive azoospermia (NOA) to give appropriate genetic counseling before assisted reproductive techniques (ART) in Middle East and to compare the frequencies with other regions of the world.

MATERIAL AND METHODS

A total of 880 Middle Eastern patients with NOA were recruited in this multicenter study for genetic evaluation prior to use of ART. Karyotyping was performed on peripheral blood lymphocytes according to standard G-banding methods, polymerase chain reaction (PCR) was performed to screen the microdeletions in the AZF region of the Y chromosome.

RESULTS

The present study shows that the total prevalence of genetic abnormalities is 28.41 %, including 184 patients (20.91 %) with chromosome disorder and 66 patients (7.5 %) with Y chromosome microdeletions. The most prevalent chromosome abnormality is Klinefelter's syndrome, which includes 161 patients (18.3 %), 7 patients had XX reversal male sex (0.8 %), 2 patients had 47XYY (0.23 %) and 2 patients had 45XO/46XY (0.23 %). Structural abnormalities occurred in 12 patients (1.36 %).

CONCLUSIONS

The high prevalence of genetic abnormalities (28.41 %) in our study strongly suggests the need for routine genetic testing and counseling prior to assisted reproduction in such population with idiopathic infertility, as a result may help determine the prognosis, as well as the choice of ART. Moreover it allows specific pre-implantation genetic testing to minimize the risk of transmitting genetic defects to offspring.

First study of microdeletions in the Y chromosome of Algerian infertile men with idiopathic oligo- or azoospermia

The human Y chromosome is essential for human sex determination and spermatogenesis. The long arm contains the azoospermia factor (AZF) region. Microdeletions in this region are responsible for male infertility. The objective of this study was to determine the frequency of Y microdeletions in Algerian infertile males with azoospermia and oligoasthenoteratozoospermia syndrome (OATS) and to compare the prevalence of these abnormalities with other countries and regions worldwide. A sample of 80 Algerian infertile males with a low sperm count (1-20 × 10(6) sperms/ml) as well as 20 fertile male controls was screened for Y chromosome microdeletions. 49 men were azoospermic and 31 men had OATS. Genomic DNA was isolated from blood and polymerase chain reaction was carried out with a set of 6 AZFa, AZFb and AZFc STS markers to detect the microdeletions as recommended by the European Academy of Andrology. Among the 80 infertile men screened for microdeletion, 1 subject was found to have microdeletions in the AZFc (sY254 and sY255) region. The deletion was found in azoospermic subjects (1/49, 2%). The overall AZF deletion frequency was low (1/80, 1.3%). AZF microdeletions were observed neither in the OATS group nor in the control group. The frequency of AZF microdeletions in infertile men from Algeria was comparable to those reported in the literature. We suggest analyzing 6 STS in the first step to detect Y microdeletions in our population.

Analysis of partial AZFc deletions in Malaysian infertile male subjects

Complete deletions in the AZF (a, b, and c) sub-regions of the Y-chromosome have been shown to contribute to unexplained male infertility. However, the role of partial AZFc deletions in male infertility remains to be verified. Three types of partial AZFc deletions have been identified. They are gr/gr, b1/b3, and b2/b3 deletions. A recent meta-analysis showed that ethnic and geographical factors might contribute to the association of partial AZFc deletions with male infertility. This study analyzed the association of partial AZFc deletions in Malaysian infertile males. Fifty two oligozoospermic infertile males and 63 fertile controls were recruited to this study. Screening for partial AZFc deletions was done using the two sequence-tagged sites approach (SY1291 and SY1191) which were analyzed using both the conventional PCR gel-electrophoresis and the high resolution melt, HRM method. Gr/gr deletions were found in 11.53% of the cases and 9.52% of the controls (p = 0.725). A B2/b3 deletion was found in one of the cases (p = 0.269). No B1/b3 deletions were identified in this study. The results of HRM analysis were consistent with those obtained using the conventional PCR gel-electrophoresis method. The HRM analysis was highly repeatable (95% limit of agreement was -0.0879 to 0.0871 for SY1191 melting temperature readings). In conclusion, our study showed that partial AZFc deletions were not associated with male infertility in Malaysian subjects. HRM analysis was a reliable, repeatable, fast, cost-effective, and semi-automated method which can be used for screening of partial AZFc deletions.

Partial microdeletions in the Y-chromosome AZFc region are not a significant risk factor for spermatogenic impairment in Tunisian infertile men

Azoospermia factor (AZF) subdeletions were reported to be significant risk factors for spermatogenesis. In this study, we screened classical and partial microdeletions of the Y-chromosome AZF region in a group of 261 infertile men. Partial deletions were also screened in a control group of fertile men (n=124). In addition, Y haplogroups were analyzed in 24 gr/gr deleted patients. Among the 261 studied infertile men, seven subjects were found to have classical microdeletions. The most common partial deletion of AZFc (gr/gr) was observed in 13.02% of infertile men and in 12.90% of fertile men. The b1/b3 deletion was identified in 4.98% of infertile men and in 2.41% of fertile men. In addition, the b2/b3 deletion was identified in 1.53% of infertile patients but not in the control group. Our results suggest that partial AZFc deletions are not associated with spermatogenic failure in the Tunisian population.

Association of spermatogenic failure with the b2/b3 partial AZFc deletion

Infertility affects around 1 in 10 men and in most cases the cause is unknown. The Y chromosome plays an important role in spermatogenesis and specific deletions of this chromosome, the AZF deletions, are associated with spermatogenic failure. Recently partial AZF deletions have been described but their association with spermatogenic failure is unclear. Here we screened a total of 339 men with idiopathic spermatogenic failure, and 256 normozoospermic ancestry-matched men for chromosome microdeletions including AZFa, AZFb, AZFc, and the AZFc partial deletions (gr/gr, b1/b3 and b2/b3).

AZFa and AZFc deletions were identified in men with severe spermatogenic failure at similar frequencies to those reported elsewhere. Gr/gr deletions were identified in case and control populations at 5.83% and 6.25% respectively suggesting that these deletions are not associated with spermatogenic failure. However, b2/b3 deletions were detected only in men with spermatogenic failure and not in the normospermic individuals. Combined with our previous data this shows an association of the b2/b3 deletion (p = 0.0318) with spermatogenic failure in some populations. We recommend screening for this deletion in men with unexplained spermatogenic failure.

Chromosomal defects in infertile men with poor semen quality

PURPOSE

To assess the incidence and the type of chromosomal aberrations in males with infertility we reviewed cytogenetic results in 76 Tunisian infertile men (54 nonobstructive azoospermia and 22 oligo-asthenospermia).

METHODS

Karyotyping was performed on peripheral blood lymphocytes according to the standard methods. Molecular diagnosis of classical and partial Y-chromosomal microdeletions was performed by amplifying Y-specific STSs markers.

RESULTS

Various numerical and structural chromosome abnormalities were identified in 15 patients (19.48%). The occurrence of chromosomal abnormality in the azoospermics and severe oligo-asthnospermic was 21.7% and 13.5%, respectively. The most common was Klinefelter syndrome, accounting for 10 of the 15 cytogenetic defects. The total frequency of Y chromosomal microdeletions was 17.1%, with respective frequencies in azoospermic and severe oligospermic groups, 11.1% and 31.8%. The most frequent of Y chromosomal deletions were the partial ones (11.1% in azoospermic and 27.2% in oligospermic).

CONCLUSION

The occurrence of chromosomal abnormalities among infertile males strongly suggests the need for routine genetic testing and counseling prior to the employment of assisted reproduction techniques.

The likelihood of finding mature sperm cells in men with AZFb or AZFb-c deletions: six new cases and a review of the literature (1994-2010)

OBJECTIVE

To reassess the predictive value of detecting sperm cells in men with AZFb or AZFb-c deletions.

DESIGN

Retrospective analysis of previously reported men with AZFb or AZFb-c deletions and the addition of six new cases.

SETTING

Fertility institution.

PATIENT(S)

Men with both sequence tagged site marker identification and testicular cytology/histology findings.

INTERVENTION(S)

Systematic review of reported men with microdeletions that included eligibility, data extraction and analysis.

MAIN OUTCOME MEASURE(S)

Availability of sperm cells for intracytoplasmic sperm injection (ICSI) in men with AZFb/AZFb-c microdeletions.

RESULT(S)

The average prevalences reported for AZFb, AZFb-c, partial AZFb, and partial AZFb-c in azoospermic men were 0.9%±0.07%, 2.7%±0.93%, 1.23%±0.9%, and 1%±0.6%, respectively. Sperm cells were identified in 7% and 3% of the 28 and 71 men with complete AZFb and AZFb-c and in 57% and 43% of the 14 and 7 men with partial AZFb and AZFb-c deletions, respectively. The likelihood of finding sperm cells in men with complete versus partial AZFb and AZFb-c deletions was significantly lower. As yet, no clinical or chemical pregnancy after ICSI in cases with complete AZFb/b-c microdeletions has been reported.

CONCLUSION(S)

Determining the extent of AZFb or AZFb-c deletions is critical considering the frequency and the reasonable prospect of finding sperm cells in partial AZFb/AZFb-c deletions. Referring men with complete AZFb/b-c microdeletions to testicular sperm extraction/ICSI programs should be revaluated.

What about gr/gr deletions and male infertility? Systematic review and meta-analysis

BACKGROUND

The impact of gr/gr deletions on male fertility is unclear. These partial deletions of the AZFc region of the Y chromosome have been detected more frequently in infertile patients. However, few individual studies have demonstrated a statistically significant association. This study aims to quantify the strength of association between gr/gr deletions and male infertility, and to explore potential sources of heterogeneity, including ethnicity and geographical location.

METHODS

Medline was searched up to 31 December 2009 for full articles investigating the prevalence of gr/gr deletions in infertile and control men. A pooled odds ratio (OR) was estimated by a random-effects model. Heterogeneity was assessed by the Cochran's Q test, and quantified by I(2) statistic.

RESULTS

A total of 18 case-control studies, including 6388 cases and 6011 controls, met our inclusion criteria and showed that gr/gr deletions were present in 6.86% of cases and 4.69% of controls. The association between gr/gr deletions and infertility was significant (P < 0.001), with a pooled random-effects OR of 1.76 (1.21-2.66) for infertile men versus normozoospermic controls (13 studies). The test for heterogeneity among studies yielded a Q test P = 0.089 with I(2) value of 37%, indicating moderate heterogeneity. The association between gr/gr deletions and infertility was dependent on ethnicity and geographic region.

CONCLUSIONS

Our meta-analysis comprising >12 000 men demonstrates that gr/gr deletions occur more frequently in infertile than control men. The association between gr/gr deletions and infertility varies according to ethnicity and geographic region, with an association reaching significance among Caucasian men, in Europe and the Western Pacific region.

Associations of Y-chromosome subdeletion gr/gr with the prevalence of Y-chromosome haplogroups in infertile patients

Microdeletions in azoospermia factor (AZF) region on distal Yq are associated with male infertility and spermatogenic failure due to intra-chromosomal homologous recombination between large nearly identical repeat amplicons and are found in ∼10% of azoospermic and severe oligozoospermic cases. Although AZFc is deleted in azoospermia or oligozoospermia, no definitive conclusion has been drawn for the role of partial AZFc deletions to spermatogenic failure. Therefore, this study is planned to investigate the role of gr/gr subdeletions in individuals with spermatogenic failure and to find its relationship with Y chromosome haplogroups (HGs) in infertile men from Indian population. It is a case-control study involving 236 azoospermic, 182 oligospermic and 240 healthy normozoospermic men. We found 18 gr/gr, 11 b1/b3 and 2 b2/b3 subdeletions in azoospermic patients and 12 gr/gr, 5 b1/b3 and 4 b2/b3 subdeletions in oligospermic patients. However, we also found seven gr/gr deletions in normozoospermic men. Seven patients each with spermatogenic arrest and oligospermia who carry gr/gr subdeletions have deleted DAZ3/DAZ4 genes. A total of 11 patients with sertoli cell-only syndrome (SCOS) and 5 oligospermic patients with gr/gr subdeletions also have DAZ1/DAZ2 genes deleted indicating that deletions of DAZ genes contributed differently to damage to spermatogenic process. L1 HG is found in patients showing b1/b3 subdeletions, whereas HG H1a2 and H1b were found in normozoospermic individuals with gr/gr subdeletions. Our results provide evidence of association between the occurrence of subdeletions and male infertility as well as the severity of the spermatogenic failure.

[Male infertility and gene defects]

About 15% of the couples at reproductive age worldwide suffer from infertility. It is estimated that 50% of the entity result from male itself. The mechanism of male infertility is quite complicated, attributing to inherent and environment factors of the infertility patients, of which defects of fertility-related genes are of importance for its occurrence. The clinical features of male infertility vary from azoospermia to oligoasthenoteratozoospermia. This paper presents the relationship between the known defects in genes and male infertility.

The AZFc region of the Y chromosome: at the crossroads between genetic diversity and male infertility

BACKGROUND

The three azoospermia factor (AZF) regions of the Y chromosome represent genomic niches for spermatogenesis genes. Yet, the most distal region, AZFc, is a major generator of large-scale variation in the human genome. Determining to what extent this variability affects spermatogenesis is a highly contentious topic in human reproduction.

METHODS

In this review, an extensive characterization of the molecular mechanisms responsible for AZFc genotypical variation is undertaken. Such data are complemented with the assessment of the clinical consequences for male fertility imputable to the different AZFc variants. For this, a critical re-evaluation of 23 association studies was performed in order to extract unifying conclusions by curtailing methodological heterogeneities.

RESULTS

Intrachromosomal homologous recombination mechanisms, either crossover or non-crossover based, are the main drivers for AZFc genetic diversity. In particular, rearrangements affecting gene dosage are the most likely to introduce phenotypical disruptions in the spermatogenic profile. In the specific cases of partial AZFc deletions, both the actual existence and the severity of the spermatogenic defect are dependent on the evolutionary background of the Y chromosome.

CONCLUSIONS

AZFc is one of the most genetically dynamic regions in the human genome. This property may serve as counter against the genetic degeneracy associated with the lack of a meiotic partner. However, such strategy comes at a price: some rearrangements represent a risk factor or a de-facto causative agent of spermatogenic disruption. Interestingly, this precarious balance is modulated, among other yet unknown factors, by the evolutionary history of the Y chromosome.

Oxidative stress and epididymal sperm transport, motility and morphological defects

OBJECTIVES

Radical oxidative species (ROS) have an important effect on sperm quality and quantity. Oxidative stress (OS) occurs when production of potentially destructive reactive oxygen species (ROS) exceeds the body's own natural antioxidant defenses, resulting in cellular damage. OS is a common pathology seen in approximately half of all infertile men. Increased ROS generation and reduced antioxidant capacity is negatively correlated with sperm concentration and motility in infertile men. For the first time, we used a more stable and reliable sensitive carbonyl protein (CP) detection method to determine ROS in seminal plasma than measuring ROS directly to clarify the effect of OS on spermatozoa in terms of protein dysfunction. This is the first report to measure CP in seminal plasma as an indicator of OS. Furthermore, for the first time we correlated the results of CP measurement with light microscopy in combination with ultrastructural analysis by electron microscopy.

MATERIAL AND METHODS

20 patients with idiopathic oligoasthenoteratozoospermia (iOAT) and 10 fertile controls were enrolled in this study. CP values were measured by enzyme-linked immuno sorbent assay (ELISA) to detect the level of OS. Transmission electron microscope (TEM) was used to detect axonemal anomalies.

RESULTS

Compared to fertile controls, statistically highly significant higher degrees of abnormal sperm parameters (P<0.001) could be found in iOAT patients. CP values were highly significantly elevated in iOAT patients than in normal controls (P<0.001). A statistically highly significant difference in different axonemal anomalies were found between iOAT patients and normal controls (P<0.001). CP values have been found to be positively correlated with different axonemal anomalies (absence of axoneme (r(2)=0.841), missing of central singlet tubules (r(2)=0.702) and missing of outer doublet tubules (r(2)=0.869). A statistically negative correlation were found between different axonemal anomalies (absent axoneme (r(2)=-0.780), missing of central singlet tubules (r(2)=-0.611), and missing of outer doublet tubules (r(2)=-0.738) and forward progressive sperm motility.

CONCLUSION

High levels of CP can be measured in iOAT patients, indicating that OS could underlie the aetipopathogenesis of the syndrome. OS negatively affects flagellar axonemal structure with subsequent impairment of forward progressive sperm motility. This can put an attention for antioxidants as a therapy for iOAT syndrome and further research to find how to decrease ROS production.

Follicle-stimulating hormone autoantibody is involved in idiopathic spermatogenic dysfunction

AIM

To detect the anti-follicle-stimulating hormone (FSH) antibody in idiopathic infertile patients and fertile subjects in order to determine the role of this antibody in patients with spermatogenic dysfunction.

METHODS

The anti-FSH antibody in serum was detected by an enzyme-linked immunosorbent assay (ELISA). The functional and structural integrity of the sperm membrane was evaluated with hypo-osmotic swelling (HOS) test and the ultrastructure of the spermatozoa was investigated by transmission electron microscopy (TEM).

RESULTS

The extent of positive FSH antibody in the patients with oligozoospermia and/or asthenozoospermia was significantly higher than that in the fertile subjects and infertile patients with normal sperm concentration and motility, but it was significantly lower than that in the patients with azoospermia. The extent of anti-FSH antibody in the patients with azoospermia was significantly greater than that in patients with oligospermia and/or asthenospermia, infertile people with normal sperm density and motility and fertile people. The hypo-osmotic swelling test showed that the percentage of HOS-positive spermatozoa (swollen) was 45.1 mu 3.5% in the FSH antibody-positive group and 59.1% micro 6.2% in the FSH antibody-negative control group. The percentage of functional membrane damage to spermatozoa was significantly higher in the anti-FSH antibody-positive group than in the control group. TEM showed that the outer acrosomal membrane was located far from the nucleus, and detachment of the acrosome was found in the FSH autoantibody-positive group.

CONCLUSION

These data suggest that the presence of anti-FSH antibody is strongly correlated with the sperm quantity and quality in idiopathic male infertility. Anti-FSH antibody may be an important factor causing spermatogenic dysfunction and infertility.

Development of a multiplex quantitative fluorescent PCR assay for identification of rearrangements in the AZFb and AZFc regions

The azoospermia factor b (AZFb) and azoospermia factor c (AZFc) regions in the human Y chromosome consist of five palindromes constructed from six distinct families of amplicons and are prone to rearrangement. Partial deletion and duplication in the region can cause azoospermia or oligozoospermia and male infertility. The aim of the study was to establish a quantitative fluorescent PCR (QF-PCR) assay to classify AZFb and AZFc rearrangements. A single pair of fluorescent primers was designed to amplify simultaneously the amplicon in AZFc and the length-variant homologous sequences outside of the region as control. Since the copy number of the control sequences is fixed in the human genome, dosage of the target could be easily obtained through comparing the height of the fluorescent peaks between the target and the control after amplification with limited PCR cycles. Most types of rearrangements in AZFb and AZFc regions could be classified with QF-PCR containing four such primer pairs. Eleven types of rearrangement in AZFb and AZFc regions were well discriminated with QF-PCR. In conclusion, QF-PCR is a simple and reliable method to detect rearrangements in AZFb and AZFc.

Do we need to search for gr/gr deletions in infertile men in a clinical setting?

BACKGROUND

Partial deletions of the AZFc region of the Y chromosome such as gr/gr deletions have been detected in infertile patients as well as in control groups. The impact of these gr/gr deletions on the etiology of male infertility remains unknown. In the present study, we investigated the presence of gr/gr deletions in Caucasian men.

METHODS

gr/gr deletions were analyzed by using markers sY1291, sY1191 and sY1197 and by investigating the presence of single nucleotide variants (SNV) in DAZ and CDY1 genes in patients with azoospermia (n = 44), cryptozoospermia (n = 51) or severe oligozoospermia (n = 92). Control groups consisted of men with normal spermatogenesis on testicular biopsy (n = 33), normozoospermia (n = 278) or proven fertility (n = 83).

RESULTS

We observed 20 gr/gr deletions, with eight in infertile patients (4.3%) and 12 in the control groups (3.0%), which was not significantly different. DAZ SNV analysis revealed eight different deletion patterns in patients and controls.

CONCLUSIONS

In the present study, no significant differences in the frequency of gr/gr deletions between different patient and control groups were observed. We concluded that the relationship between gr/gr deletions and male infertility remains unclear and that it is too early to systematically test for gr/gr deletions for infertile couples seeking assisted reproduction treatment.