Browsing by Author "Sandeep Kumar Bansal"

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Autosomal genes in male infertility
(Springer Singapore, 2017) Vertika Singh; Sandeep Kumar Bansal; Rajender Singh; Kiran Singh
Spermatogenesis is driven by the master genes present on the Y chromosome. These driver genes need support from numerous other genes spread across the genome for a number of actions such as energy metabolism, cell death and apoptosis, protein turnover, synthesis of new proteins and garbage disposal. Preliminary studies on infertility focused on the Y chromosome genes due to their primary and indispensable role in spermatogenesis. A number of other studies on human infertility and mouse knockouts have identified several spermatogenically important genes present on chromosomes other than X and Y. For some of these genes, molecular pathways they participate in have also been worked out. This chapter summarizes the genes present on the autosomes that facilitate the process of spermatogenesis and fertility. © Springer Nature Singapore Pte Ltd. 2017. All rights reserved.
Gr/gr deletions on Y-chromosome correlate with male infertility: An original study, meta-analyses, and trial sequential analyses
(Nature Publishing Group, 2016) Sandeep Kumar Bansal; Deepika Jaiswal; Nishi Gupta; Kiran Singh; Rima Dada; Satya Narayan Sankhwar; Gopal Gupta; Singh Rajender
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.
Is MTHFR 677 C>T polymorphism clinically important in Polycystic Ovarian Syndrome (PCOS)? A case-control study, meta-analysis and trial sequential analysis
(Public Library of Science, 2016) S. Justin Carlus; Saumya Sarkar; Sandeep Kumar Bansal; Vertika Singh; Kiran Singh; Rajesh Kumar Jha; Nirmala Sadasivam; Sri Revathy Sadasivam; P.S. Gireesha; Kumarasamy Thangaraj; Singh Rajender
Background: Optimum efficiency of the folate pathway is considered essential for adequate ovarian function. 677 C>T substitution in the 5, 10-methylene tertrahydrofolatereductase (MTHFR) gene compromises activity of the MTHFR enzyme by about 50%. The significance of correlation between 677C>T substitution and PCOS remains dubious due to the low power of published studies. Methods and Results: We analyzed MTHFR 677 C>T site in ethnically two different PCOS case-control groups (total 261 cases and 256 controls) from India. The data analysis revealed a lack of association between this polymorphism and PCOS [OR = 1.11 (95%CI = 0.71-1.72), P = 0.66]. Group-wise analysis on the basis of ethnicity also revealed no association in any of the ethnic groups [Indo-Europeans, P = 1; Dravidians, P = 0.70]. Homocysteine levels did not differ significantly between cases (15.51 μmol/L, SD = 2.89) and controls (15.89 μmol/L, SD = 2.23). We also undertook a meta-analysis on 960 cases and 1028 controls, which suggested a significant association of the substitution with PCOS in the dominant model of analysis (OR = 1.47 (95%CI = 1.04-2.09), P = 0.032]. Trial sequential analysis corroborated findings of the traditional meta-analysis. However, we found that the conclusions of meta-analysis were strongly influenced by studies that deviated from the Hardy Weinberg equilibrium. A careful investigation of each study and a trial sequential analysis suggested that 677 C>T substitution holds no clinical significance in PCOS in most of the populations. Conclusion: In conclusion, MTHFR 677 C>T polymorphism does not affect PCOS risk in India. The association seen in the meta-analysis is due to an outlier study and studies showing deviation from the Hardy Weinberg equilibrium. © 2016 Carlus et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Sex chromosomal genes in male infertility
(Springer Singapore, 2017) Sandeep Kumar Bansal; Vertika Singh; Kiran Singh; Rajender Singh
Y chromosome harbors the male-specific region (MSY) that regulates male sex determination and spermatogenesis. Y microdeletions are the most common cause of male infertility. These deletions are found in 15-20% of patients with idiopathic azoospermia and 7-10% of patients with severe oligozoospermia. Apart from microdeletions, partial deletions in the AZFc region result in loss of multiple copies of Y genes and increase the risk of infertility. A few studies have suggested that routine screening of these deletions could help in understanding the etiology, offering counseling and managing infertility by natural or assisted methods. X being a homologue chromosome of Y has drawn attention regarding the presence of spermatogenic genes. A number of theories and speculations have been put forward that are now supported by the identification of a number of testis-specific or testis-predominant genes present on the X chromosome. This chapter provides an overview of the Y deletions and X chromosome genes that affect spermatogenesis or male fertility. © Springer Nature Singapore Pte Ltd. 2017. All rights reserved.
SNPs in ERCC1, ERCC2, and XRCC1 genes of the DNA repair pathway and risk of male infertility in the Asian populations: association study, meta-analysis, and trial sequential analysis
(Springer New York LLC, 2019) Vertika Singh; Sandeep Kumar Bansal; D.V.S. Sudhakar; Neelabh; Arijit Chakraborty; Sameer Trivedi; Gopal Gupta; Kumarasamy Thangaraj; Singh Rajender; Kiran Singh
Purpose: We investigated if substitutions in the ERCC1, ERCC2, and XRCC1 genes of the DNA repair pathway correlate with non-obstructive azoospermia and male infertility. Methods: A total of 548 azoospermic infertile males and 410 fertile controls were genotyped for XRCC1 399A > G, 280G > A, and ERCC1 C > A 3′ UTR and 541 azoospermic infertile males and 416 fertile controls were genotyped for ERCC2 751A > C using iPLEX Gold Assay. Meta-analyses were performed on XRCC1 399A > G (1022 cases and 1004 controls), ERCC1 C > A 3′ UTR (879 cases and 1059 controls), and ERCC2 751A > C (914 cases and 850 controls) polymorphisms to quantitatively estimate the significance of the association between these polymorphisms and the risk of infertility. Results: Statistically significant association between ERCC2 751A > C SNP and male infertility was found using the codominant model (p = 0.03). Results of meta-analysis suggested a lack of correlation with male infertility risk, which could be due to pooling of studies from different ethnic populations. Due to limited the number of studies, a stratified analysis for different ethnic groups could not be performed. Conclusion (s): In conclusion, AA genotype of 751A > C SNP in ERCC2 correlated with a higher risk of male infertility and may contribute to an increased risk of azoospermia and male infertility in Indian men. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.