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

Detection of AZF microdeletions and analysis of reproductive hormonal profiles in Hainan men undergoing assisted reproductive technology

BACKGROUND

Male infertility has become a global health problem, and genetic factors are one of the essential causes. Y chromosome microdeletion is the leading genetic factor cause of male infertility. The objective of this study is to investigate the correlation between male infertility and Y chromosome microdeletions in Hainan, the sole tropical island province of China.

METHODS

We analyzed the semen of 897 infertile men from Hainan in this study. Semen analysis was measured according to WHO criteria by professionals at the Department of Reproductive Medicine, the First Affiliated Hospital of Hainan Medical University, where samples were collected. Y chromosome AZF microdeletions were confirmed by detecting six STS markers using multiple polymerase chain reactions on peripheral blood DNA. The levels of reproductive hormones, including FSH, LH, PRL, T, and E2, were quantified using the enzyme-linked immunosorbent assay (ELISA).

RESULTS

The incidence of Y chromosome microdeletion in Hainan infertile men was 7.13%. The occurrence rate of Y chromosome microdeletion was 6.69% (34/508) in the oligozoospermia group and 7.71% (30/389) in the azoospermia group. The deletion of various types in the AZF subregion was observed in the group with azoospermia, whereas no AZFb deletion was detected in the oligozoospermia group. Among all patients with microdeletions, the deletion rate of the AZFc region was the higher at 68.75% (44 out of 64), followed by a deletion rate of 6.25% (4 out of 64) for the AZFa region and a deletion rate of 4.69% (3 out of 64) for the AZFb region. The deletion rate of the AZFa region was significantly higher in patients with azoospermia than in patients with oligozoospermia (0.51% vs. 0.39%, p < 0.001). In comparison, the deletion rate of the AZFc region was significantly higher in patients with oligozoospermia (3.08% vs. 6.30%, p < 0.001). Additionally, the AZFb + c subregion association deletion was observed in the highest proportion among all patients (0.89%, 8/897), followed by AZFa + b + c deletion (0.56%, 5/897), and exclusively occurred in patients with azoospermia. Hormone analysis revealed FSH (21.63 ± 2.01 U/L vs. 10.15 ± 0.96 U/L, p = 0.001), LH (8.96 ± 0.90 U/L vs. 4.58 ± 0.42 U/L, p < 0.001) and PRL (263.45 ± 21.84 mIU/L vs. 170.76 ± 17.10 mIU/L, p = 0.002) were significantly increased in azoospermia patients with microdeletions. Still, P and E2 levels were not significantly different between the two groups.

CONCLUSIONS

The incidence of AZF microdeletion can reach 7.13% in infertile men in Hainan province, and the deletion of the AZFc subregion is the highest. Although the Y chromosome microdeletion rate is distinct in different regions or populations, the regions mentioned above of the Y chromosome may serve an indispensable role in regulating spermatogenesis. The analysis of Y chromosome microdeletion plays a crucial role in the clinical assessment and diagnosis of male infertility.

An azoospermic male with a novel chromosome 46, XX, der(15)t(Y; 15)(p11.3; p12)

Male individuals with a 46, XX karyotype are commonly diagnosed with 46, XX male sex reversal syndrome, one of the rarest sex chromosomal anomalies. In this case, we report a rare XX male with Y‐specific DNA sequences located near the end of chromosome 15 p‐arm, which was verified by fluorescent in situ hybridization (FISH) as well as copy number variation sequencing (CNV‐seq) based on the next‐ generation sequencing method (>100 Kb). To the best of our knowledge, there have been no reports of XX male with the Yp region transferred to the terminal of chromosome 15 short arm.

We report an azoospermia male with a novel chromosome 46, xx, der(15)t(Y; 15)(p11.3; p12) by CNV‐seq combined with traditional karyotype analysis and FISH. To the best of our knowledge, there have been no reports of XX male with the Yp region transferred to the terminal of chromosome 15 short arm.

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.

Y chromosome microdeletion screening using a new molecular diagnostic method in 1030 Japanese males with infertility

The azoospermia factor (AZF) region is important for spermatogenesis, and deletions within these regions are a common cause of oligozoospermia and azoospermia. Although several studies have reported this cause, the present research, to the best of our knowledge, is the first large-scale study assessing this factor in Japan. In this study, 1030 male patients with infertility who were examined for Y chromosome microdeletion using the polymerase chain reaction-reverse sequence-specific oligonucleotide (PCR-rSSO) method, a newly developed method for Y chromosome microdeletion screening, were included. The study enrolled 250 patients with severe oligospermia and 717 patients with azoospermia. Among the 1030 patients, 4, 4, 10, and 52 had AZFa, AZFb, AZFb+c, and AZFc deletions, respectively. The sperm recovery rate (SRR) of microdissection testicular sperm extraction in patients with AZFc deletions was significantly higher than that in those without AZF deletions (60.0% vs 28.7%, P = 0.04). In patients with gr/gr deletion, SRR was 18.7%, which was lower than that in those without gr/gr deletion, but was not statistically significant. In conclusion, our study showed that the frequency of Y chromosome microdeletion in male patients in Japan was similar to that reported in patients from other countries, and SRR was higher in patients with AZFc deletion.

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.

Early detection of Y chromosome microdeletions in infertile men is helpful to guide clinical reproductive treatments in southwest of China

The microdeletions of azoospermia factor (AZF) genes in Y chromosome are greatly associated with male infertility, which is also known as the second major genetic cause of spermatogenetic failure. Accumulating studies demonstrate that the different type of AZF microdeletions in patients reflect different clinical manifestations. Therefore, a better understanding of Y chromosome microdeletions might have broad implication for men health. In this study, we sought to determine the frequency and the character of different Y chromosome microdeletion types in infertile men in southwest of China.In total, 1274 patients with azoospermia and oligozoospermia were recruited in southwest of China and screening for Y chromosome microdeletions in AZF regions by multiplex polymerase chain reaction.The incidence of AZF microdeletions in southwest of China is 12.87%, which is higher than the national average. Further investigations unveiled that azoospermia factor c (AZFc) is the most frequent type of all the AZF microdeletions. Additionally, the number and also the quality of sperm in patients with AZFc microdeletion is decreasing with the age. Therefore, it is conceivable that the early testing for Y chromosome microdeletions in infertile men is crucial for fertility guidance.The early detection of Y chromosome microdeletions in infertile men can not only clearly explain the etiology of oligzoospermia and azoospermia, but also help for the clinical management of both infertile man and his future male offspring.

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.

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.

Y chromosome microdeletions and varicocele as aetiological factors of male infertility: A cross-sectional study

The pathogenic mechanisms by which varicocele disrupt spermatogenesis are not clearly understood. Over 30% of male infertility cases resulting from spermatogenic problems are associated with genetic abnormalities, and Y chromosome microdeletions are the second most frequent genetic cause. Here, we aimed to evaluate the frequency of Y chromosome microdeletion in infertile men with varicocele. A cross-sectional study comprising 51 infertile men with varicocele presenting spermatogenesis failures was performed. Y chromosome microdeletion research was made using polymerase chain reaction. Of the 51 men with infertility and varicocele, 35.3% (18/51) had nonobstructive azoospermia and 64.7% had severe oligozoospermia. Y chromosome microdeletion was found in two cases (3.9%): one patient had nonobstructive azoospermia and complete microdeletion of the AZFb and AZFc regions, and another patient had severe oligozoospermia and complete microdeletion of the AZFc region. Although in recent years, a genetic aetiology related to Y chromosome microdeletions has become a major cause of infertility in males with spermatogenesis failures, in this study, the varicocele was the clinical cause of seminal abnormalities that could lead to infertility, suggesting that both varicocele and Y chromosome microdeletion aetiologies can present, alone or combined, as factors of male infertility.

Human Y chromosome copy number variation in the next generation sequencing era and beyond

The human Y chromosome provides a fertile ground for structural rearrangements owing to its haploidy and high content of repeated sequences. The methodologies used for copy number variation (CNV) studies have developed over the years. Low-throughput techniques based on direct observation of rearrangements were developed early on, and are still used, often to complement array-based or sequencing approaches which have limited power in regions with high repeat content and specifically in the presence of long, identical repeats, such as those found in human sex chromosomes. Some specific rearrangements have been investigated for decades; because of their effects on fertility, or their outstanding evolutionary features, the interest in these has not diminished. However, following the flourishing of large-scale genomics, several studies have investigated CNVs across the whole chromosome. These studies sometimes employ data generated within large genomic projects such as the DDD study or the 1000 Genomes Project, and often survey large samples of healthy individuals without any prior selection. Novel technologies based on sequencing long molecules and combinations of technologies, promise to stimulate the study of Y-CNVs in the immediate future.