Y chromosome micro-deletions in idiopathic infertility from Northern India. ACTA ACUST UNITED AC. 2004;47:331-337. [PMID: 15581830 DOI: 10.1016/j.anngen.2004.05.003]

Prevalence of Y chromosome microdeletion in azoospermia factor subregions among infertile men from West Bengal, India

Background

Etiology of male infertility is intriguing and Y chromosome microdeletion within azoospermia factor (AZF) sub‐regions is considered major cause. We conducted a screening for Y chromosome microdeletion in an infertile male cohort from West Bengal, India to characterize Y chromosome microdeletion among infertile men.

Methods

We recruited case subjects that were categorized on the basis of sperm count as azoospermia (N = 63), severe oligozoospermia (N = 38), and oligozoospermia (N = 17) and compared them with age, demography, and ethnicity matched healthy proven fertile control males (N = 84). Sequence Tagged Site makers and polymerase chain reaction based profiling of Y chromosome was done for AZF region and SRY for cases and controls.

Results

We scored 16.1% of cases (19 out of 118) that bear one or more microdeletions in the studied loci and none among the controls. The aberrations were more frequent among azoospermic males (17 of 19) than in severe oligozoospermic subjects (2 of 19).

Conclusion

Our study provides the results of screening of the largest Bengali infertile men sample genotyped with the maximum number of STS markers spanning the entire length of Y chromosome long arm. Y chromosome microdeletion is a significant genetic etiology of infertility among Bengali men.

Mild androgen insensitivity syndrome (MAIS): the identification of c.1783C>T mutation in two unrelated infertile men

Two unrelated men complaining of primary male infertility presented to Orient Hospital in Damascus city. Physical examination showed moderate hypoandrogenic features. Both men were azoospermic. Hormone profiles revealed an elevation of follicle-stimulating hormone in one patient, but all the other hormones tested were within normal limits for both patients. Further genetic analyses, including karyotype and microdeletions in the AZF region of the Y chromosome, were normal in both patients. Mild androgen insensitivity syndrome was expected in the two patients. Sequencing analysis of the first exon in the androgen receptor (AR) gene have shown c.1783C>T mutation in the two patients with azoospermia. This paper sheds light on the need to screen for mutations in the AR gene, causing male infertility whenever mild hypoandrogenic features are present with unexplained male infertility.

Correlation of genetic results with testicular histology, hormones and sperm retrieval in nonobstructive azoospermia patients with testis biopsy

To investigate the frequency and types of genetic results in different testicular histology of patients with nonobstructive azoospermia (NOA), and correlated with hormones and sperm retrieval (SR), a retrospective study was conducted in 286 Chinese NOA patients who underwent testis biopsy and 100 age-matched fertile men as the control group. Chromosome karyotype analyses were performed by the peripheral blood chromosome G-band detection method. Screening of Y chromosome microdeletions of azoospermia factor (AZF) region was performed by polymerase chain reaction (PCR) amplification of 11 sequence-tagged sites (STS). The serum levels of follicle-stimulating hormone, luteinising hormone and testosterone (T) and the appearance of scrotal ultrasound were also obtained. In 286 cases of NOA, 14.3% were found to have chromosomal alterations. The incidence of chromosomal abnormality was 2.8%. Sex chromosomal abnormalities were seen in six cases (four cases of Klinefelter's syndrome (47, XXY) and two cases of mosaics). The incidence of polymorphic chromosomal variants was 3% in the normal group and 11.5% in the NOA group. In total, 15.7% of NOA patients were found to have AZF microdeletions and AZF (c + d) was the most frequent one. The results of hormone and SR were found to be significantly different among all testicular histological types, whereas no significant differences were found when it comes to genetic alterations. It is concluded that the rate of cytogenetic alterations was high in NOA patients. So screening for chromosomal alterations and AZF microdeletions would add useful information for genetic counselling in NOA patients with testis biopsy and avoid vertical transmission of genetic defects by assisted reproductive technology.

Genetics and male infertility

The goal of this review is to explain the requirement for understanding the genetic structure of infertility arising from male factor and to discuss the essentials of these genetic elements (2). The majority of the population is affected by this disorder caused by male factor infertility (1); but the etiologies are still unknown. After the primary genetic structure in infertile phenotypes is searched, an evaluation can be made. Thus the reasons causing infertility can be discovered and patients can benefit from effective therapies (1). Publications about male infertility within the recent 10 years in the Pubmed database were discussed (1). There are some approachments for describing the function of specific genes, but no adequate study is present to be useful for diagnosing and treating male infertility (1). Male fertility and fertility in offspring of males are considerably affected by the exact transition of epigenetic information (1). When the genetic factors playing a role in male infertility were analysed, significant steps will be taken for treating patients and determining the reasons of idiopathic infertility (1). Developments in technology associated with the impact of genetics may enable to specify the etiology of male infertility by determining specific infertile phenotype marks (1).

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.

Y chromosome microdeletions in infertile men: prevalence, phenotypes and screening markers for the Indian population

PURPOSE

Yq microdeletions are the leading genetic cause of male infertility and its detection is clinically relevant for appropriate genetic counseling. We aimed to determine the prevalence and type of Yq microdeletions, the associated seminal phenotypes and the STS markers that are relevant for its testing in Indian population.

METHODS

Yq microdeletion analysis was carried out in 1,636 infertile cases in our centers. Additional data was collected from published studies in Indian population leading to a total of 3,647 cases.

RESULTS

In our cohort, 3.4 % (56/1,636) of infertile men had Yq microdeletions. Combining the data from other published studies identified 215/3,647 (5.8 %) infertile individuals to harbor Yq microdeletions; with 6.4 % in azoopsermia, 5.8 % in oligozoospermia and 3.2 % in oligoasthenozoospermia and teratozoospermia cases. No significant differences in the deletion frequencies were observed between idiopathic vs non idiopathic cases (5.8 vs 8.6 % respectively). Deletions of AZFc were at highest frequency (46.6 %) with double deletions most commonly observed in azoospermic subjects. With respect to the STS markers, screening with the six European Academy of Andrology (EAA) markers would miss 3.1 % of cases; additional non EAA markers that would contribute significantly to screening are sY746, sY82, sY121, sY128, sY130, sY143, sY145 & sY160.

INTERPRETATIONS AND CONCLUSIONS

The frequency of Yq microdeletions is lower in Indian population as compared to Western counterparts. There is no major association of Yq microdeletions with seminal parameters or cause of infertility. Clinically it will be necessary to offer Yq microdeletion testing to all the classes of infertile men. The EAA markers may not be adequate to detect microdeletions in Indian infertile men.

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 azoospermia factor locus-c region was found to be related to Klinefelter syndrome in Turkish patients

We looked for a possible association between Klinefelter syndrome (KFS) and microdeletions in the Y chromosome in Turkish KFS patients. We examined the frequency of KFS in male patients with proven non-obstructive azoospermia and the types of Y chromosome microdeletions in these KFS patients. Fifty azoospermic patients and 50 fertile men were included in this study. KFS was found in 14 azoospermic patients. Y chromosome microdeletions were found in eight KFS patients. Azoospermia factor locus c (AZFc) was the most commonly deleted interval in KFS patients. All KFS patients had elevated plasma follicle-stimulating hormone and luteinizing hormone concentrations, but they had normal plasma testosterone concentrations. Testis biopsy of five samples with Y microdeletions revealed Sertoli cell-only syndrome. No Y microdeletions were found in the fertile group. We concluded that there could be an association between the AZFc region and KFS. Screening for this should be part of diagnostic work-up, particularly in those considering assisted reproduction.

Clinical consequences of microdeletions of the Y chromosome: the extended Münster experience

A total of 3179 patients were screened for Y-chromosome microdeletions and 821 patients for partial AZFc deletions. Thirty-nine Y-chromosomal microdeletions were found (2.4% of men with <1 x 10(6)/ml spermatozoa): two AZFa, two AZFb, one AZFbc, one partial AZFb, one partial AZFb+c and 32 AZFc (b2/b4). Partial AZFc deletions were found in 45 patients (5.5%), mostly gr/gr deletions (n = 28). In patients with AZFc deletion, azoospermia was found in 53.1% and sperm concentrations of mostly <0.1 x 10(6)/ml were found in 46.9%. Semen analyses and FSH measurements showed no trend over time. Elongated spermatids were seen in 6/15 AZFc patients and bilateral Sertoli cell-only was found in 4/15. Testicular sperm extraction (TESE) was attempted in 10 patients and spermatozoa were found in six. Compared with infertile men matched by sperm concentration, no differences in hormonal and seminal parameters could be found in patients with AZFc or gr/gr deletions. It is concluded that: (i) frequency of AZF deletions in Germany is much lower than in other countries; (ii) AZFc deletions are associated with severe disturbances of spermatogenesis and TESE is not possible in half of these patients; (iii) AZFc and gr/ gr deletions are not associated with any clinical diagnostic parameter; (iv) and no trend is apparent over time.

SRY and AZF gene variation in male infertility: a cytogenetic and molecular approach

AIM

The aim of this study was to identify the genetic effects of Y chromosome and azoospermia factor (AZF) gene variation in men with infertility and to elucidate the molecular mechanism responsible for the identified point mutation.

METHODS

Chromosome analysis was performed according to standard methods on lymphocyte cultured cells and genomic DNA was extracted from the peripheral blood. Three sets of primers were used encompassing the AZFb, AZFc and SRY14 gene regions. Products were genotyped with single-strand comformational polymorphisim (SSCP) analysis.

RESULTS

The profiles of the mutated genes were detected in five of three azoospermic and two oligoasthenozoospermic infertile males. The SSCP variability of the AZFc gene was detected in all of the cases, while sex-determining region Y (SRY) gene variation was detected in two of the current cases. Three cases with oligoasthenozoospermia showed mutated SSCP profiles in both their SRY and AZFc gene regions. No AZFb variation was detected in the presented cases.

CONCLUSION

The AZF locus is assumed to contain the genes responsible for spermatogenesis in human. Deletions in these genes are thought to be involved in male infertility associated with azoospermia, oligozoospermia and/or both. AZF microdeletions and variations that are seen in infertile males suggest the need for molecular screening of such cases. Advance studies are also needed to detect of these variations and their relevance to male infertility before using assisted reproduction techniques in such cases.

Application of multiplex bead array assay for Yq microdeletion analysis in infertile males

The purpose of this study was to apply the multiplex bead array as a diagnostic tool for male infertility. The multiplex bead array offers a new platform in high-throughput nucleic acid detection. Six loci, including sex-determining regions on the Y (SRY) chromosome as a control and five sequence-tagged sites (STS) in azoospermia-factor regions, were used in this system. Extracted genomic DNA from infertile male blood was used for multiplex polymerase chain reaction (PCR). After multiplex PCR using specific Cy3-labeled primer sets, the PCR product was hybridized with capture probes. A multiplexed PCR-liquid bead was arrayed for simultaneous detection using the Luminex system. This assay system correctly identified the presence or deletion of the Y chromosome. Therefore, this method provides a sensitive and high-throughput method for probing the deletion of the Y chromosome, and offers a completely new approach to male infertility screening.

Y-chromosomal microdeletions and partial deletions of the Azoospermia Factor c (AZFc) region in normozoospermic, severe oligozoospermic and azoospermic men in Sri Lanka

AIM

To assess for the first time the occurrence of Y chromosomal microdeletions and partial deletions of the Azoospermia Factor c (AZFc) region in Sri Lankan men and to correlate them with clinical parameters.

METHODS

In a retrospective study, we analyzed 96 infertile men (78 with non-obstructive azoospermia) and 87 controls with normal spermatogenesis. AZFa, AZFb, AZFc and partial deletions within the AZFc region were analyzed by multiplex polymerase chain reaction (PCR) according to established protocols.

RESULTS

No AZFa, AZFb or AZFc deletions were found in the control group. Seven patients in the group of infertile men were found to have deletions as following: one AZFa, two AZFc, two AZFbc and two AZFabc. The relative distribution of these patterns was significantly different compared with that found in the German population. Extension analysis confirmed that the deletions occurred according to the current pathogenic model. gr/gr deletions were found to be equally present both in the patients (n=4) and in the control group (n=4). One b2/b3 deletion was found in the patient group.

CONCLUSION

These results suggest that the frequency and pattern of microdeletions of the Y chromosome in Sri Lankan men are similar to those found in other populations and confirm that gr/gr deletions are not sufficient to cause spermatogenetic failure.