Loss of the AZFc region due to a human Y-chromosome microdeletion in infertile male patients

The Association of Partial Azoospermia Factor C Deletions and Male Infertility in Northwestern China

BACKGROUND

Male infertility is a major health issue worldwide. Y chromosome microdeletions are well-characterized genetic causes of male infertility. The association of partial AZFc deletions (gr/gr, b2/b3, and b1/b3) with male infertility is not well confirmed in diverse populations. The purpose of the present study was to investigate the frequency of partial AZFc deletions and their association with male infertility in a population from Northwestern China.

METHODS

Multiplex polymerase chain reaction was used to detect partial AZFc deletions in 228 infertile patients. We analyzed 141 cases of azoospermia (AS), 87 cases of oligozoospermia (OS), and 200 fertile controls.

RESULTS

Our data showed that the frequency of a b2/b3 deletion in infertile men, men with AS, men with OS, and controls was 3.51, 2.13, 5.75, and 0.00%, respectively. The frequency of this deletion was significantly different between the infertile group and the control group (3.51 vs. 0.00%, respectively, p = 0.021) and between the OS group and the control group (5.75 vs. 0.00%, respectively, p = 0.003). The frequency of a gr/gr deletion in each group was 11.84, 9.22, 16.09, and 7.50%, respectively. The frequency of a gr/gr deletion was significantly different between the OS group and the control group (16.09 vs. 7.50%, respectively, p = 0.026) but not between the infertile group and the control group (11.84 vs. 7.50%, p = 0.132) or the AS group and the control group (9.22 vs. 7.50%, p = 0.569). The frequency of a b1/b3 deletion was 0.44, 0.71, 0.00, and 3.00%, respectively. For this deletion, there was no significant difference between the infertile (0.44 vs. 3.00%, p = 0.089), AS (0.71 vs. 3.00%, p = 0.276), and OS groups (0.00 vs. 3.00%, p = 0.236) and the control group.

CONCLUSIONS

Our results suggest that the b2/b3 deletion might be associated with male infertility and that the gr/gr deletion might be associated with spermatogenic failure in men with OS in Northwestern China (Ningxia).

Gene Scanning for Microdeletions in the Azoospermia Factor Region of Y-Chromosome in Infertile Men of Gujarat, India

INTRODUCTION

Azoospermia Factor (AZF) microdeletions in Yq chromosome is one of the most frequent genetic cause associated with failure of spermatogenesis in males with infertility.

AIM

To figure out the Yq chromosome microdeletions frequency in infertile men from Gujarat region of India.

MATERIALS AND METHODS

In this study, 141 infertile men with azoospermia (n=41) and oligozoospermia (n=100) were examined along with 159 normozoospermic men. Eleven different markers spanning the azoospermia factor region of human Yq chromosome, amplified by sequence-tagged site Polymerase Chain Reaction (PCR) to detect the microdeletions. Sperm morphological analysis was done using papanicolau staining method.

RESULTS

Thirty four infertile men out of 141 presented Yq chromosome microdeletions. The frequency of AZF microdeletions was 31.71% in azoospermia and 21% in oligozoospermia patients. Only two oligozoospermia patients showed morphological defects.

CONCLUSION

Due to the presence of high frequency of Yq chromosome microdeletions in Gujarati infertile men, it is imperative to implement the AZF microdeletion screening in such patients as it results in male spermatogenesis dysfunctioning.

The sperm quality and clinical outcomes were not affected by sY152 deletion in Y chromosome for oligozoospermia or azoospermia men after ICSI treatment

Azoospermia factor (AZF) microdeletion plays a key role in the genetic etiology of male infertility. The relationship between sY152 deletion in the AZFc region and clinical outcomes is still unclear. This study was to determine the effects of sY152 deletion on the sperm parameters and clinical outcomes of non-obstructive azoospermia or oligozoospermia men after intracytoplasmic sperm injection (ICSI) treatment. A total of 61 infertile men with AZFc microdeletion of the Y chromosome from January 2008 to December 2012 were recruited in the present study. They were divided into two groups, the sY152 group (n=12) and the AZFc group (n=49), based upon whether they have deleted single sY152 marker or all AZFc markers. Fifty azoospermia or oligozoospermia patients without Y chromosome microdeletion were included as the control group. The sperm quality and clinical data were compared among the three groups. Retrospective cohort-control study was performed. The sperm concentration and motility in sY152 group were better than AZFc group (P<0.05), and were comparable to the control group (P>0.05); the morphology, seminal zinc, seminal fructose and seminal carnitine were similar among the three groups (P>0.05). Patients in both sY152 and AZFc groups had lower fertilization rates (68.40% and 70.63%, respectively) than those in the control group (74.91%), and the differences were statistically significant (P<0.05). No significant differences were found in terms of MII oocyte, high-grade embryo rate, 2PN zygote, number of available embryos and transferred embryos, clinical pregnancy rate, implantation rate, miscarriage rate, multiple pregnancy rate, delivery rate, preterm rate and the male/female ratio among the three groups (P>0.05). Single sY152 deletion might cause a lower fertilization rate, but no adverse effects on sperm quality and clinical outcomes were found. Our study may provide more information for consultation in these patients.

Decrease in fertilization and cleavage rates, but not in clinical outcomes for infertile men with AZF microdeletion of the Y chromosome

This study aimed to explore whether the presence of a Y chromosome azoospermia factor (AZF) microdeletion confers any adverse effect on embryonic development and clinical outcomes after intracytoplasmic sperm injection (ICSI) treatment. Fifty-seven patients with AZF microdeletion were included in the present study and 114 oligozoospermia and azoospermia patients without AZF microdeletion were recruited as controls. Both AZF and control groups were further divided into subgroups based upon the methods of semen collection: the AZF-testicular sperm extraction subgroup (AZF-TESE, n = 14), the AZF-ejaculation subgroup (AZF-EJA, n = 43), the control-TESE subgroup (n = 28) and the control-EJA subgroup (n = 86). Clinical data were analyzed in the two groups and four subgroups respectively. A retrospective case-control study was performed. A significantly lower fertilization rate (69.27 versus 75.70%, P = 0.000) and cleavage rate (89.55 versus 94.39%, P = 0.000) was found in AZF group compared with the control group. Furthermore, in AZF-TESE subgroup, the fertilization rate (67.54 versus 74.25%, P = 0.037) and cleavage rate (88.96 versus 94.79%, P = 0.022) were significantly lower than in the control-TESE subgroup; similarly, the fertilization rate (69.85 versus 75.85%, P = 0.004) and cleavage rate (89.36 versus 94.26%, P = 0.002) in AZF-EJA subgroup were significantly lower than in the control-EJA subgroup; however, the fertilization rate and cleavage rate in AZF-TESE (control-TESE) subgroup was similar to that in the AZF-EJA (control-EJA) subgroup. The other clinical outcomes were comparable between four subgroups (P > 0.05). Therefore, sperm from patients with AZF microdeletion, obtained either by ejaculation or TESE, may have lower fertilization and cleavage rates, but seem to have comparable clinical outcomes to those from patients without AZF microdeletion.

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.

Unbalanced translocation involving partial trisomy 9p and partial monosomy yq with neurodevelopmental delays

We present a 4-year-old Honduran boy with mild neurodevelopmental delays, growth delays, dysmorphic features, and small genitalia. Chromosome analysis initially revealed a single X chromosome and a marker chromosome derived from the short arm of chromosome 9 which was consistent with Turner syndrome as only 1 sex chromosome could be identified. However, on further analysis, he was found to have an unbalanced translocation involving the short arm of chromosome 9 and the long arm of the Y chromosome. The translocation resulted in partial trisomy 9p and partial monosomy Yq. The patient's clinical features are felt to be the result of partial trisomy 9p. In addition, partial monosomy Yq is associated with male infertility. Testing of the patient's parents was normal, indicating this was a de novo translocation. Additional evaluations of this child and his parents allowed an accurate assessment of his diagnosis, long-term prognosis, and chance of recurrence.

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.