Exosome-mediated transfer of miR-1260b promotes cell invasion through Wnt/ß-catenin signaling pathway in lung adenocarcinoma.

Increasing evidence confirms that exosome-mediated transfer of microRNAs can influence cancer progression including tumor cell invasion, cell proliferation, and drug resistance via cell-cell communication. However, the potential role of exosomal-miR-1260b in lung adenocarcinoma (LAC) remains poorly understood. Thus, this study focused on investigating the function of exosomal-miR-1260b on cell invasion. Exosomal-miR-1260b was found to be higher in plasma of patients with LAC than that of healthy persons via quantitative real-time polymerase chain reaction assay. The sensitivity and specificity of exosomal-miR-1260b (cutoff point: 2.027) were 72% and 86%, and area under the curve of 0.845 (95% CI = 0.772-0.922). Elevated expression of miR-1260b in LAC tissues was positively correlated with exosomal-miR-1260b in plasma (r = .642, p < .05). Furthermore, ceramide biosynthesis regulated exosomal-miR-1260b secretion. Exosome-mediated transfer of miR-1260b promoted A549 cell invasion and was still functional inside A549 cells. Moreover, exosomal-miR-1260b regulated Wnt/ß-catenin signaling pathway by inhibiting sFRP1 and Smad4. This study identified a new regulation mechanism involving in cell invasion by exosome-mediated tumor-cell-to-tumor-cell communication. Targeting exosome-microRNAs may provide new insights into the diagnosis and treatment of LAC.

Site-Specific Covalent Conjugation of Modified mRNA by tRNA Guanine Transglycosylase.

Modified mRNA (mod-mRNA) has recently been widely studied as the form of RNA useful for therapeutic applications due to its high stability and lowered immune response. Herein, we extend the scope of the recently established RNA-TAG (transglycosylation at guanosine) methodology, a novel approach for genetically encoded site-specific labeling of large mRNA transcripts, by employing mod-mRNA as substrate. As a proof of concept, we covalently attached a fluorescent probe to mCherry encoding mod-mRNA transcripts bearing 5-methylcytidine and/or pseudouridine substitutions with high labeling efficiencies. To provide a versatile labeling methodology with a wide range of possible applications, we employed a two-step strategy for functionalization of the mod-mRNA to highlight the therapeutic potential of this new methodology. We envision that this novel and facile labeling methodology of mod-RNA will have great potential in decorating both coding and noncoding therapeutic RNAs with a variety of diagnostic and functional moieties.

A predictive model for high-quality blastocyst based on blastomere number, fragmentation, and symmetry.

PURPOSE: The aim of this study was to create a predictive model for high-quality blastocyst progression based on the traditional morphology parameters of embryos. METHODS: A total of 1564 embryos from 234 women underwent conventional in vitro fertilization and were involved in the present study. High-quality blastocysts were defined as having a grade of at least 3BB, and all embryos were divided based on the development of high-quality blastocysts (group HQ) or the failure to develop high-quality blastocysts (group NHQ). A retrospective analysis of day-3 embryo parameters, focused on blastomere number, fragmentation, the presence of a vacuole, symmetry, and the presence of multinucleated blastomeres was conducted. RESULTS: All parameters were related to high-quality blastocysts (p < 0001) in t tests, chi-square tests, or Fisher tests. The individual scores for all parameters were determined according to their distributions and corresponding rates of forming high-quality blastocysts. Parameters are indicated by s_bn (blastomere number), s_f (fragmentation), s_pv (presence of a vacuole), s_s (symmetry), and s_MNB (multinucleated blastomeres). Subsequently, univariate and multivariate logistic regression analyses were conducted to explore their relationship. In the multivariate logistic regression analysis, a predictive model was constructed, and a parameter Hc was created based on the s_bn, s_f, and s_s parameters and their corresponding odds ratios. The value of Hc in group HQ was significantly higher than that in group NHQ. A receiver operating characteristic curve was used to test the effectiveness of the model. An area under the curve of 0.790, with a 95% confidence interval of 0.766-0.813, was calculated. A dataset was used to validate the predictive utility of the model. Moreover, another dataset was used to ensure that the model can be applied to predict the implantation of day-3 embryos. CONCLUSIONS: A predictive model for high-quality blastocysts was created based on blastomere number, fragmentation, and symmetry. This model provides novel information on the selection of potential embryos.

Light-Activated Control of Translation by Enzymatic Covalent mRNA Labeling.

Activation of cellular protein expression upon visible-light photocleavage of small-molecule caging groups covalently attached to the 5' untranslated region (5' UTR) of an mRNA was achieved. These photocleavable caging groups are conjugated to in vitro transcribed mRNA (IVT-mRNA) through RNA transglycosylation, an enzymatic process in which a bacterial tRNA guanine transglycosylase (TGT) exchanges a guanine nucleobase in a specific 17-nucleotide motif (Tag) for synthetic pre-queuosine1 (preQ1 ) derivatives. The caging groups severely reduce mRNA translation efficiency when strategically placed in the 5' UTR. Using this method, we demonstrate the successful spatiotemporal photoregulation of gene expression with single-cell precision. Our method can be applied to therapeutically relevant chemically modified mRNA (mod-mRNA) transcripts. This strategy provides a modular and efficient approach for developing synthetic gene regulatory circuits, biotechnological applications, and therapeutic discovery.

Site-Specific Covalent Labeling of RNA by Enzymatic Transglycosylation.

We demonstrate the site-specific incorporation of nucleobase derivatives bearing fluorophores or affinity labels into a short RNA stem loop recognition motif by exchange of a guanine residue. The RNA-TAG (transglycosylation at guanosine) is carried out by a bacterial (E. coli) tRNA guanine transglycosylase (TGT), whose natural substrate is the nitrogenous base PreQ1. Remarkably, we have successfully incorporated large functional groups including biotin, BODIPY, thiazole orange, and Cy7 through a polyethylene glycol linker attached to the exocyclic amine of PreQ1. Larger RNAs, such as mRNA transcripts, can be site-specifically labeled if they possess the 17-nucleotide hairpin recognition motif. The RNA-TAG methodology could facilitate the detection and manipulation of RNA molecules by enabling the direct incorporation of functional artificial nucleobases using a simple hairpin recognition element.

Chromoblastomycosis due to Fonsecaea monophora in a man with nephritic syndrome.

Chromoblastomycosis is a chronic subcutaneous mycosis caused by dematiaceous fungi. Fonsecaea monophora, a new species segregated from F. pedrosoi, may be the most prevalent pathogen of chromoblastomycosis in southern China. Herein, we report a rare case of chromoblastomycosis in a man with nephritic syndrome. He presented with an asymptomatic red plaque on the back of his left wrist that had appeared and enlarged over a period of 1.5 years, without any prior trauma. He was initially diagnosed with sporotrichosis. However, he did not respond to a 6-month course of potassium iodide treatment. The lesion slowly enlarged and became verrucous instead. Concurrently, a similar maculopapule appeared on his left forearm. Histopathological examination of a biopsy specimen indicated the presence of sclerotic bodies in the dermis. The fungus was identified as Fonsecaea spp. based on the results of a slide culture; in addition, the agent was confirmed to be F. monophora by using molecular methods. The patient demonstrated marked improvement after receiving appropriate antifungal therapy for 3 months. To our knowledge, this is the first case of chromoblastomycosis caused by F. monophora in an immunosuppressed patient. The identification of the agent by molecular techniques is important for epidemiological purposes. Thus, we believe that combination therapy with itraconazole and terbinafine would be a suitable option for infections caused by F. monophora.

Polymorphism in DNMT1 may modify the susceptibility to oligospermia.

As an important methyltransferase, DNMT1 plays a key role in DNA methylation that is essential for normal spermatogenesis, which suggests that it may be involved in male infertility with spermatogenesis impairment. To explore the relationship between DNMT1 and spermatogenesis impairment, polymorphic distributions of single-nucleotide polymorphisms (SNP) rs16999593, rs2228612 and rs2228611 in DNMT1 were investigated in 342 infertile patients with idiopathic azoospermia or oligospermia and 232 fertile controls in a Chinese population. As a result, no significant differences in allele and genotype frequencies of the three SNP between total patients and controls were observed. However, after stratifying the patients, significant differences in allele and genotype frequencies were detected between oligospermia subgroup and control group. The frequencies of rs16999593 allele A (83.6% versus 77.6%, P=0.033) and genotype AA (69.2% versus 59.0%, P=0.037) and SNP rs2228611 genotype AA (18.4% versus 9.9%, P=0.016) in patients with oligospermia were significantly higher than those in control group. These findings suggest that the polymorphism in DNMT1 might be associated with oligospermia and could modify the susceptibility of oligospermia.

Association of common SNP rs1136410 in PARP1 gene with the susceptibility to male infertility with oligospermia.

PURPOSE: This study aims to explore possible associations between polymorphisms of common SNP rs1136410 and rS1805405 in PARP1 gene and male infertility with spermatogenesis impairment. METHODS: The polymorphic distributions of SNP rs1136410 and rS1805405 were investigated by polymerase chain reaction and restriction fragment length polymorphism analysis in a Chinese cohort including 371 infertile patients with idiopathic azoospermia or oligospermia and 231 controls. RESULTS: Significant differences in the frequencies of allele and genotype of SNP rs1136410 were observed between patients with oligospermia and controls. The allele C (46.3 % vs. 36.4 %, P = 0.003) and genotype CC (22.6 % vs. 13.4 %, P = 0.014) significantly increased, whereas genotype TT (30 % vs. 40.7 %, P = 0.021) significantly decreased in patients with oligospermia compared with controls at this SNP locus. CONCLUSIONS: These results indicated that genotype CC of SNP rs1136410 may increase the risk of oligosoermia and genotype TT of rs1136410 may have some protective effect from oligospermia, suggesting that the polymorphism of SNP rs1136410 in PARP1 gene may modify the susceptibility to male infertility with oligospermia.

Null genotype of GSTM1 and GSTT1 may contribute to susceptibility to male infertility with impaired spermatogenesis in Chinese population.

Glutathione-S-transferases (GSTs) play a protective role during spermatogenesis and GST genes may be involved in impaired spermatogenesis. A case-control study was performed to explore the association of genes GSTM1 and GSTT1, two members of GST gene family, with spermatogenesis impairment. The deletion polymorphism distribution of genes GSTM1 and GSTT1 was investigated in 353 patients with azoospermia or oligospermia and 201 fertile controls in Chinese population using multiplex PCR. As a result, the frequencies of null genotype of genes GSTM1 (67.4% versus 57.7%, p = 0.022, OR = 1.516, 95% CI = 1.001-2.168) and GSTT1 (61.8% versus 46.8%, p = 0.001, OR = 1.838, 95% CI = 1.295-2.610) in patients were significantly higher than those in controls. After stratifying patients, the frequencies of null genotype of gene GSTM1 in oligospermia (68.3% versus 57.7%, p = 0.027, OR = 1.580, 95% CI = 1.051-2.375) and GSTT1 in azoospermia (66.9% versus 46.8%, p < 0.001, OR = 2.299, 95% CI = 1.484-3.562) as well as oligospermia (57.9% versus 46.8%, p = 0.025, OR = 1.567, 95% CI = 1.057-2.322) were still significantly higher compared with controls. The results suggested that null genotypes of GSTM1 and GSTT1 are associated with spermatogenesis impairment and may contribute to susceptibility to spermatogenesis impairment and male infertility in Chinese population.

Genetic variants of eNOS gene may modify the susceptibility to idiopathic male infertility.

In testis, eNOS is responsible for synthesis of nitric oxide (NO) which is an essential gas message regulator in spermatogenesis, suggesting that eNOS gene plays a role in normal spermatogenesis and the genetic variants of eNOS gene may be potential genetic risk factors of spermatogenesis impairment. In this study, the polymorphic distributions of three common polymorphism loci including T-786C, 4A4B and G894T in eNOS gene were investigated in 355 Chinese infertile patients with azoospermia or oligozoospermia and 246 healthy fertile men and a meta-analysis was carried in order to explore the possible relationship between the three loci of eNOS gene and male infertility with spermatogenesis impairment. As a result, allele -786C of T-786C (11.4% versus 6.5%, p = 0.004) and 4A of 4A4B (11.0% versus 6.3%, p = 0.005) as well as genotype TC of T-786C (22.8% versus 13.0%, p = 0.002) and AB of 4A4B (18% versus 11%, p = 0.015) were significantly associated with idiopathic male infertility. The haplotypes T-4A-G (7.4% versus 4.1%, p = 0.015) and C-4B-G (7.6% versus 4.4%, p = 0.028) could increase the susceptibility to male infertility, whereas haplotype T-4B-G (67.0% versus 75.2%, p = 0.002) might be a protective factor for male infertility. The results of meta-analysis revealed that the polymorphism of T-786C was associated with male infertility. These findings suggested that the variants of eNOS gene may modify the susceptibility to male infertility with impaired spermatogenesis.

SNPs in KIT and KITLG genes may be associated with oligospermia in Chinese population.

KIT/KITLG signaling system is crucial for spermatogenesis, which suggests that KIT and KITLG genes may be involved in spermatogenesis impairment and male infertility. To explore the possible association of KIT and KITLG genes with male infertility having spermatogenesis impairment, polymorphism distributions of SNP rs3819392 in KIT gene as well as rs995030 and rs4474514 in KITLG gene were investigated in 372 patients with idiopathic azoospermia or oligospermia and 205 fertile controls. As a result, the significant differences in polymorphism distributions of SNP rs3819392 in KIT gene and rs4474514 in KITLG gene were observed between the patients with oligospermia and controls. The frequencies of allele G (94.2% versus 90.0% p = 0.022) and genotype GG (89.2% versus 82.0% p = 0.042) in patients with oligospermia were significantly higher than those in controls at rs3819392 locus in KIT gene. In addition, the genotype CC of rs4474514 in KITLG (8.2% versus 3.4%, p = 0.034) also significantly increased in oligospermic patients in comparison to controls. These findings indicated that SNP rs3819392 in KIT gene and rs4474514 in KITLG gene may be associated with oligospermia, suggesting that polymorphism of KIT and KITLG genes may play a role in oligospermia.

Association between single-nucleotide polymorphisms of DNMT3L and infertility with azoospermia in Chinese men.

The gene for DNA methyltransferase 3-like protein (DNMT3L) is essential for normal spermatogenesis and may be involved with spermatogenetic impairment and male infertility. To explore the possible association between the DNMT3L gene and male infertility, this study investigated allele, genotype and haplotype frequencies of three single nucleotide polymorphism (SNP) loci, rs2070565, rs2276248 and rs7354779, of DNMT3L in 233 infertile patients with azoospermia and 249 fertile controls from a population of Chinese men using polymerase chain reaction/restriction fragment length polymorphism. Results showed that the frequencies of allele A (20.6% versus 14.9%; P = 0.022) and the allele A carrier (GA + AA; 37.8% versus 28.1%; P = 0.027) in azoospermic patients were significantly higher than those in controls at the rs2070565 locus. The haplotype AAA frequency was significantly higher (18.1% versus 12.4%; P = 0.02) while the haplotype GAA frequency was significantly lower (53.2% versus 62.1%; P = 0.007) in infertile patients compared with fertile controls. These results indicated that SNP rs2070565, as well as haplotypes AAA and GAA, may be associated with male infertility and suggest that DNMT3L may contribute to azoospermia susceptibility in humans.

Relationship of SNP of H2BFWT gene to male infertility in a Chinese population with idiopathic spermatogenesis impairment.

The H2B family, member W, testis specific (H2BFWT) gene encodes a testis specific histone that plays a crucial role in reorganization and remodeling of chromatin and epigenetic regulation during spermatogenesis, suggesting that the gene may be involved in spermatogenesis impairment. To test the speculation, the allele and haplotype frequencies of two single-nucleotide polymorphism loci in this gene, -9C>T and 368A>G, were investigated in 409 infertile patients with idiopathic azoospermia or oligozoospermia and 209 fertile men as controls using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) assay. As the results, the frequencies of -9T (52.8% vs. 41.6%, p = 0.009) and 368G (43.0% vs. 32.5%, p = 0.012) were significantly higher in patients than those in controls; after stratifying patients, the significant higher frequencies were still detected in allele -9T for azoospermia (57.4% vs. 41.6%, p = 0.001) and allele 368G for oligozoospermia (45.4% vs. 32.5%, p = 0.007). The haplotype CA was significantly decreased (22.8% vs. 33.0%, p = 0.006) whereas TG was significantly increased (18.3% vs. 7.2%, p < 0.001) in infertile patients compared with controls. These results indicated that the polymorphism -9C>T and 368A>G in H2BFWT gene are associated with male infertility with idiopathic azoospermia or oligozoospermia, suggesting that H2BFWT gene might be contribute to susceptibility to spermatogenesis impairment in Chinese population.

The Motivation of Media Users and China's National Media Digitization Construction in the Post-COVID-19 Era.

The sudden arrival of COVID-19 has had an enormous impact on the lives of people around the world, including significant psychological pressure and increased emotional needs. In China, research into user psychology and the motivations of commercial digital media has become more popular, but the national media should pay more attention to user psychology and perform more research on user motivations to improve the effectiveness of communication. We investigated people's internal psychology and motivation for using national media digital platforms in China during the pandemic. We collected data through online questionnaires and analyzed the use of apps of CCTV and The People's Daily by individual users during the pandemic and the psychological needs of national digital media users. In the first stage of our research, we selected national digital media app users through the WeChat platform. In the second stage, more active users were chosen by snowballing upon the original sample. We surveyed 210 participants and ultimately obtained 180 valid samples. We analyzed the data using used SPSS 23.0. The results showed that with the help of digital media platforms and diversified media technology, the Chinese national media not only met the needs of users for information acquisition, but also provided sufficient emotional mutual assistance and comfort to users through the network aggregation formed by digital scene communication.

[Single nucleotide polymorphisms of the genes related with spermatogenesis impairment].

Male infertility is a complex disease affecting the reproduction of childbearing couples, for which genetic polymorphism of spermatogenesis genes is an important genetic pathogenic factor. Lots of genes closely related with spermatogenesis have been successfully identified through the gene knockout technology. Spermatogenesis impairment related genes include those associated with expression enzymes, receptors, cell apoptosis, transcription regulation, and so on. The genetic susceptibility of these genes, infection, and environment jointly contribute to non-obstructive azoospermia and oligozoospermia in males. The analysis of the single nucleotide polymorphism (SNP) of spermatogenesis impairment related genes helps explain the possible mechanism of pathogenesis at the molecular level, and provides theoretical evidence for the clinical diagnosis and treatment of male infertility. The article focuses on the correlation of the SNPs of spermatogenesis impairment related genes with azoospermia and oligozoospermia.

Phenotypic and molecular characterization of Madurella pseudomycetomatis sp. nov., a novel opportunistic fungus possibly causing black-grain mycetoma.

A case of black-grain mycetoma occurring on the lower jaw with an odontogenic origin, which to our knowledge is the first case reported in China, is presented here. The clinical manifestation, histopathological morphology, and microbiological features are described. The new species, Madurella pseudomycetomatis, isolated from the black grains discharged by this patient, was analyzed using sequence data of the multiloci of ribosomal DNA (rDNA) and its ability to ferment carbohydrate as well as morphology. The analyses of the internal transcribed spacer (ITS) region and the D1/D2 hypervariable region of the 28S ribosomal gene sequences support a new species designation. Antifungal susceptibility testing was conducted, indicating that Madurella pseudomycetomatis was highly susceptible to itraconazole, voriconazole, and amphotericin B; moderately susceptible to terbinafine; and resistant to fluconazole and flucytosine.

[Association of single nucleotide polymorphisms of PATZ1 gene with azoospermia].

OBJECTIVE: To study the relationship between the polymorphisms of single nucleotide polymorphisms(SNPs) in rs2240424, rs2057951, rs2240427 and rs714909 loci in the PATZ1 gene and azoospermia. METHODS: The allele and genotype frequencies of the four SNPs were investigated in 180 patients with azoospermia and 190 normal men as controls by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis. The allele and genotype frequencies of the four SNPs were investigated in 180 patients with azoospermia and 190 normal men as controls by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis. RESULTS: The frequencies of allele C (35.0% vs. 27.6%, P=0.031) and individuals with allele C (TC+CC) (57.8% vs. 46.3%, P=0.027) at the rs2057951 locus in azoospermic patients were significantly higher than that in normal men. There was a significant difference in distribution of haplotypes of the four SNPs between the two groups (P=0.01). Hapoltypes ACAC (11.1% vs. 6.6%, P=0.029) and ACGC (11.2% vs. 5.2%, P=0.003) increased significantly in azoospermic patients compared with controls. CONCLUSION: The allele C of rs2057951 locus and haplotypes ACAC and ACGC of the four SNPs in PTAZ1 gene increased the susceptibility to azoospermia, suggesting that PATZ1gene may be associated with azoospermia.

Associations of Common Single Nucleotide Polymorphisms in miR-34b/c and miR-499 with Male Infertility Caused by Oligospermia or Azoospermia in the Chinese Population.

Aims: The present study was designed to survey the associations between polymorphisms of the common single nucleotide polymorphism (SNP) rs4938723 in the miR-34b/c gene, as well as the rs3746444 SNP in the miR-499 gene, and impairment of spermatogenesis leading to oligospermia and azoospermia in the Chinese population. Subjects and Methods: Specimens were collected from four hundred seventeen infertile men with oligospermia or azoospermia and 234 controls for this investigation. Polymerase chain reaction and restriction fragment length polymorphism analyses was used for genotyping the rs4938723 and rs3746444 SNPs. A chi-square analysis was used to compare the differences in allelic and genotypic frequencies between patients and controls. Results: The distribution of alleles at the rs3746444 locus of the miR-499 gene in patients was not significantly different from controls. There were, however, significant differences in the genotypic (p = 0.040) and allelic (p = 0.021) distributions of the rs4938723 SNPs between patients with oligospermia and controls. The CC genotype at the rs4938723 locus was significantly higher in in patients with oligospermia than controls (13.9% vs. 7.3%, p = 0.016, odds ratio = 2.064, 95% confidence interval 1.132-3.764). Conclusion: The CC genotype of the rs4938723 locus in the miR-34b/c gene may enhance susceptibility to oligospermia.

Association of the common SNPs in RNF212, STAG3 and RFX2 gene with male infertility with azoospermia in Chinese population.

OBJECTIVE: The aim of this study was to explore the association between the SNP rs4045481 in RNF212 gene, rs1050482 and rs11531577 in STAG3 gene as well as rs2288846 in RFX2 gene and male infertility with azoospermia in Chinese population. STUDY DESIGN: Two hundreds and twenty infertile patients with azoospermia and 248 fertile men were recruited in the present study. The four SNPs investigated were genotyped using polymerase chain reaction and restriction fragment length polymorphism assay. The differences in allelic and genotypic frequencies between patients and controls were evaluated by chi-square test. RESULTS: No significant differences in allele and genotype frequencies of SNP rs1050482 and rs11531577 in STAG3 gene as well as rs2288846 in RFX2 gene between patients with azoospermia and controls were observed. However, the frequencies of allele C(43.6% vs. 34.1%, P = 0.003, OR = 1.498, 95% CI 1.150-1.192) and genotype CC (24.6% vs. 12.0%, P = 0.001, OR = 2.346, 95% CI 1.448-3.858) were significantly higher in patients with azoospermia than those in controls at the rs4045481 locus in RNF212 gene. CONCULUSION: The polymorphism of SNP rs4045481 in RNF212 gene might be associated with azoospermia and genotype CC of this SNP may be a risk factor of azoospermia.

Single nucleotide polymorphism C677T in the methylenetetrahydrofolate reductase gene might be a genetic risk factor for infertility for Chinese men with azoospermia or severe oligozoospermia.

AIM: To analyze the distribution of the single nucleotide polymorphism (SNP) C677T in the methylenetetrahydrofolate reductase (MTHFR) gene in 355 infertile Chinese patients with idiopathic azoospermia or severe oligozoospermia and 252 fertile Chinese men as controls to explore the possible association of the SNP and male infertility. METHODS: Using the polymerase chain reaction (PCR)-restriction fragment length polymorphism technique, the allele and genotype distribution of SNP C677T in the MTHFR gene were investigated in both patients and controls. RESULTS: The frequencies of allele T (40.9% vs 30.4%, P = 0.002, odds ration [OR] = 1.58, 95% confidence interval [CI]: 1.24-2.02) and mutant homozygote (TT) (18.3% vs. 11.5%, P=0.023, OR=1.72, 95% CI: 1.07-2.76) as well as carrier with allele (TT + CT) (63.4% vs. 49.2%, P = 0.0005, OR = 1.79, 95% CI: 1.29-2.48) in infertile patients were significantly higher than those in controls. After patient stratification, the significant differences in distribution of the SNP between each patient subgroup and control group still remained. CONCLUSION: Our findings indicate that there is an association of SNP C677T in the MTHFR gene with male infertility, suggesting that this polymorphism might be a genetic risk factor for male infertility in Chinese men.