Scanning of Y-chromosome azoospermia factors loci using real-time polymerase chain reaction and melting curve analysis

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.

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.

Multicentre study of Y chromosome microdeletions in 1,808 Chinese infertile males using multiplex and real-time polymerase chain reaction

Azoospermia factor (AZF) genes on the long arm of the human Y chromosome are involved in spermatogenesis, and microdeletions in the AZF region have been recognised to be the second major genetic cause of spermatogenetic failure resulting in male infertility. While screening for these microdeletions can avoid unnecessary medical and surgical treatments, current methods are generally time-consuming. Therefore, we established a new method to detect and analyse microdeletions in the AZF region quickly, safely and efficiently. In total, 1,808 patients with spermatogenetic failure were recruited from three hospitals in southern China, of which 600 patients were randomly selected for screening for Y chromosome microdeletions in AZF regions employing real-time polymerase chain reaction with a TaqMan probe. In our study, of 1,808 infertile patients, 150 (8.3%) were found to bear microdeletions in the Y chromosome using multiplex PCR, while no deletions were found in the controls. Among the AZF deletions detected, two were in AZFa, three in AZFb, 35 in AZFc, three in AZFb+c and two in AZFa+b+c. Our method is fast-it permits the scanning of DNA from a patient in one and a half hours-and reliable, minimising the risk of cross-contamination and false-positive and false-negative results.

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.

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.

A one-step real-time multiplex PCR for screening Y-chromosomal microdeletions without downstream amplicon size analysis

Backgound

Y-chromosomal microdeletions (YCMD) are one of the major genetic causes for non-obstructive azoospermia. Genetic testing for YCMD by multiplex polymerase chain reaction (PCR) is an established method for quick and robust screening of deletions in the AZF regions of the Y-chromosome. Multiplex PCRs have the advantage of including a control gene in every reaction and significantly reducing the number of reactions needed to screen the relevant genomic markers.

Principal Findings

The widely established “EAA/EMQN best practice guidelines for molecular diagnosis of Y-chromosomal microdeletions (2004)” were used as a basis for designing a real-time multiplex PCR system, in which the YCMD can simply be identified by their melting points. For this reason, some AZF primers were substituted by primers for regions in their genomic proximity, and the ZFX/ZFY control primer was exchanged by the AMELX/AMELY control primer. Furthermore, we substituted the classical SybrGreen I dye by the novel and high-performing DNA-binding dye EvaGreen™ and put substantial effort in titrating the primer combinations in respect to optimal melting peak separation and peak size.

Significance

With these changes, we were able to develop a platform-independent and robust real-time based multiplex PCR, which makes the need for amplicon identification by electrophoretic sizing expendable. By using an open-source system for real-time PCR analysis, we further demonstrate the applicability of automated melting point and YCMD detection.

SCREENING OF Y CHROMOSOME MICRODELETIONS IN TUNISIAN INFERTILE MEN

The aim of this study was to establish the prevalence of Y chromosomal microdeletions in infertile Tunisian men. Three groups of infertile men, 65 normospermic, 53 oligozoospermic and 45 azoospermic, were tested for Yq microdeletions detection by multiplex polymerase chain reaction (PCR) using specific Y chromosome AZF regions tagged site markers (STS). One group of 13 healthy men was used as the control group. Six STS were tested (2 in each AZF region). The general prevalence of AZF microdeletions was 16%; in azoospermia and severe oligospermia groups, it was higher (29% and 30.5%, respectively). Significant differences were found with moderate oligospermic and normospermic groups (p < 0,05). AZFc microdeletions were the most frequent, and 55% of AZFc deleted patients were oligospermic. No deletions were detected in the control group. These results add to the growing literature data, showing that microdeletions of the Y chromosome is an important cause of severe spermatogenetic defect and confirm that deletion in AZFc region is the most common and is compatible with residual spermatogenesis.

Rapid multiplexing and simultaneous detection of human spermatogenetic failure with a 12 lane microchip electrophoresis system

For the amplification and ultrafast separation of the genetic markers and DNA sequences that are related to human male infertility, a multiplex PCR for amplifying three DNA sequence-tagged sites (STS) located on the human Y chromosome with possible roles in the spermatogenesis process has been designed and applied followed by separation on a microchip. First, the optimum T(m) degree for the three DNA markers was optimized and determined experimentally, and the three DNA STS were amplified. These three DNA markers were then separated on a 12-lane microchip electrophoresis system, which can analyze the DNA markers on 12 channels simultaneously. The combination of these two technologies, multiplex PCR and microchip electrophoresis, allows the analysis of 36 DNA markers (12x3) within only 180 s.

Y-chromosome microdeletions and recurrent pregnancy loss

OBJECTIVE

To determine the prevalence of Y-chromosome microdeletions in recurrent pregnancy loss (RPL) couples as compared with couples with male factor infertility and fertile couples.

DESIGN

Controlled clinical study.

SETTING

Andrology laboratory and RPL clinic.

PATIENT(S)

Seventeen men from RPL couples, 18 men from couples with a live birth and no history of miscarriages, and 10 men from couples with male factor infertility.

INTERVENTION(S)

Buccal smears for Y-chromosome microdeletion testing.

MAIN OUTCOME MEASURE(S)

The DNA was tested for microdeletions in the proximal AZFc region by polymerase chain reaction (PCR).

RESULT(S)

Fourteen of the 17 men (82%) tested had microdeletions in one or more of the four segments studied. Two of the 10 male factor infertility patients (20%) had microdeletions in 2 different segments. None of the 18 fertile men had any microdeletions in the 4 segments of the proximal AZFc region studied.

CONCLUSION(S)

The prevalence of the Y-chromosome microdeletions in the proximal AZFc region was much higher in men from RPL couples than from fertile or infertile couples. Although these patients are from a tertiary referral center that may skew the population and findings, one may consider Y-chromosome microdeletion testing particularly of the AZFc region in the evaluation of RPL couples when all other tests fail to reveal the etiology.

Specific haplotypes of the CALPAIN-5 gene are associated with polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common endocrine disorder in women of reproductive age. The aim of the present study was to investigate the role of CALPAIN-5 (CAPN5) gene in PCOS susceptibility.

METHODS

We analysed four intronic polymorphisms of the CAPN5 gene in 148 well-characterized women with PCOS and 606 unrelated controls. We performed a case-control study and an intracohort analysis of clinical characteristics associated with PCOS.

RESULTS

Analysis of haplotypes distribution between PCOS population compared to controls showed a strong deviation (P = 0.00029). The haplotypes GGCA and GGTG were overrepresented in PCOS patients (P = 0.009 and P = 0.001, respectively). In addition, we identified several CAPN5 haplotypes associated with phenotypic differences observed between PCOS patients, such as the presence of obesity (P = 0.02), cardiovascular complications (P = 0.02), familial antecedents of obesity (P = 0.003) and of hypertension (P = 0.007) and type 2 diabetes mellitus aggregation (P = 0.04).

CONCLUSIONS

These results suggest a role of CAPN5 gene in PCOS susceptibility in humans. Moreover, novel candidate risk alleles have been identified, within CAPN5 gene, which could be associated with important phenotypic and prognosis differences observed in PCOS patients.

Ultrafast diagnosis of the genetic-related disorders using the combined technologies of multiplex PCR and multichannel microchip electrophoresis

For the diagnosis of unexplained male infertility a multiplex PCR for 6 markers, which are well-known as candidate genes for studying male infertility and located on the human Y-chromosome, has been designed. The multiplex PCR products have been separated on a 12 channel microchip electrophoresis system, which can analyze different samples simultaneously. By combining the technologies of multiplex PCR with multichannel microchip electrophoresis, the number of the DNA markers that can be screened simultaneously is increased to be 72 marker (12 x 6) in a single run while the electrophoresis analysis time is reduced to be only 180 s.

Computational analysis and refinement of sequence structure on chromosome 22q11.2 region: application to the development of quantitative real-time PCR assay for clinical diagnosis

The low-copy repeat (LCR) is a new class of repetitive DNA element and has been implicated in many human disorders, including DiGeorge/velocardiofacial syndrome (DGS/VCFS). It is now recognized that nonallelic homologous recombination (NAHR) through LCRs flanking the chromosome 22q11.2 region leads to genome rearrangements and results in the DGS/VCFS. To refine the structure and content of chromosome 22q11.2 LCRs, we applied computational analysis to dissect region-specific LCRs using publicly available sequences. Nine distinct duplicons between 1.6 and 65 kb long and sharing >95% sequence identity were identified. The presence of these sequence motifs supports the NAHR mechanism. Further sequence analysis suggested that the previously defined 3-Mb deletion may actually comprise two deletion intervals of similar size close to each other and thus indistinguishable when using fluorescence in situ hybridization (FISH) analysis. The differentially deleted regions contain several hypothetical proteins and UniGene clusters and may partially explain the clinical heterogeneity observed in DGS/VCFS patients with the 3-Mb common deletion. To implement further sequence information in molecular medicine, we designed a real-time quantitative PCR assay and validated the method in 122 patients with suspected DGS/VCFS. The assay detected 28 patients with chromosome 22q11.2 deletion later confirmed using FISH. Our results indicated that the developed assay is reliable as well as time and cost effective for clinical diagnosis of chromosome 22q11.2 deletion. They also suggest that this methodology can be applied to develop a molecular approach for clinical detection and diagnosis of other genomic disorders.

Multilocus analyses of estrogen-related genes reveal involvement of the ESR1 gene in male infertility and the polygenic nature of the pathology

OBJECTIVE

To examine whether polymorphisms within the ESR1, FSHR, ESR2, CYP19A1, and NRIP1 genes are susceptibility factors for human male idiopathic infertility and to test the joint effects of these genes on male reproductive function.

DESIGN

Genetic association study of male infertility with polymorphisms, using both single-gene and multilocus approaches.

SETTING

Private and public fertility units and a private center for biomedical research.

PATIENT(S)

One hundred four Spanish men with azoospermia or severe oligozoospermia and 95 unselected race-matched healthy controls from the same geographic region.

INTERVENTION(S)

Peripheral blood extraction, DNA purification, and ESR1 g.938T>C, FSHR Ser680Asn, ESR2 *39A>G, CYP19A1 *19C>T, and NRIP1 Gly75Gly polymorphism analyses.

MAIN OUTCOME MEASURE(S)

Single-gene statistical analyses and multilocus statistical analyses with Sumstat, Permutation and Model-free analysis, and Estimating Haplotypes software.

RESULT(S)

We observed an excess of homozygous infertile men for the ESR1 g.938T>C marker. Multilocus analyses detected genetic interaction between the five candidate gene markers that are influential over male infertility. In addition, we detected a five-loci protector genetic pattern with a frequency of 9.4% in controls but absent in infertile men.

CONCLUSION(S)

Our results support a relevant role for the estrogenic pathway, notably the ESR1 gene, in human male reproductive function and advocate a complex trait model for male infertility.

Absence of de novo Y-chromosome microdeletions in male children conceived through intracytoplasmic sperm injection

Molecular screening for Y-chromosome microdeletions in 96 Spanish male children conceived through intracytoplasmic sperm injection (ICSI) was conducted. No microdeletions were detected; these results support the notion that de novo Y-chromosome alterations are rare and unrelated to the ICSI technique itself.