| Objective（s）:Schizophrenia（Schizophrenia,SCZ）is a group of common severe psychosis characterized by impaired thinking,emotion,behavior and cognitive dysfunction,which is a major global public health problem.Its etiology is complex and unclear,and currently only rely on symptomatology for diagnosis,with the lack of recognized specific biological markers.The heritability of schizophrenia reaches 81%and is considered to be a complex disease caused by a combination of genetic and environmental factors.In this study,we plan to explore the single nucleotide polymorphism（Single nucleotide polymorphism,SNP）,methylation in the promoter region and its risk factors,analyze the gene expression level,find the potential biological markers of schizophrenia,to provide a theoretical basis for the pathogenesis of schizophrenia,prevention and diagnosis treatment,and provide potential biological indicators for the judicial identification of schizophrenia,which has important socio-economic significance.Methods:1.Genomic DNA was collected from the peripheral blood of schizophrenia patients（207）and healthy controls（186）.Combining NCBI,SZDB 2.0 database and domestic and foreign literature reports,8 SNP sites（rs10332,rs12304225,rs16934358,rs2023588,rs2113879,rs4931240,rs679087,rs7503）of TMTC1 gene were screened according to MAF>0.1.Genotyping was performed using SNPscan TMmultiplex SNP typing,and the results of SNP sites in the TMTC1 gene were analyzed using SPSS 26.0 software,SHEsis Plus,SNPstats online analysis platform and MDR3.0.2 software.2.Schizophrenia patients（100）and healthy controls（100）were randomly selected from the samples collected above,and the extracted genomic DNA was treated with bisulfite with the EZ DNA Methylation-Gold?Kit kit.Cp G islands within the region 2K upstream of the transcription start site to 1K downstream of the first exon were selected.High-throughput sequencing was performed by Methyl Target TMthrough Illumina Hiseq platform,and the DNA methylation level of the promoter region of the TMTC1 gene were analyzed with the collected sample information（14 biochemical indicators and environmental factors）and schizophrenia,Graphpad Prism 9.0 and AI software mapping.3.Peripheral blood from schizophrenia patients（38）and healthy subjects（35）was collected,m RNA extracted and relative m RNA levels measured using real-time（RT-q PCR）;serum was isolated and protein expression levels measured using enzyme-linked immunosorbent assay（ELISA）.The obtained data were statistically analyzed using SPSS 26.0 software and graphed with Graphpad Prism 9.0 software.Results:1.In the overall sample,the distribution of rs12304225 allele frequencies of the me QTL locus in the TMTC1 gene was significantly different between the case and control groups,and this locus was not significant between the two groups in the male and female samples.The distribution of allele frequencies in the remaining seven SNP sites rs10332,rs16934358,rs2023588,rs2113879,rs4931240,rs679087,and rs7503was not significantly different in the case and control groups in the overall,male and female samples.The distribution of genotype frequencies for all SNP loci in the overall sample,male and female samples was not significantly different between the case and control groups.There was no significant difference in the genotype distribution of all TMTC1 SNP sites between cases and controls under different apparent recessive inheritance patterns.There was a high linkage disequilibrium between rs10332 and rs16934358,rs10332 and rs2023588,rs12304225 and rs679087,rs16934358 and rs2023588,and rs16934358,and rs7503,and there was no significant difference in the distribution of the eight haplotypes（H1 to H8）constructed.Analysis of interactions between each SNP sites in the TMTC1 gene suggested that rs10332/rs12304225/rs2113879 is the best model,with cross-validation agreement of 9/10and P<0.0001,indicating that locus rs12304225 may interact with rs10332 and rs2113879,which can predict the correlation of schizophrenia.2.The overall methylation of the promoter region of the TMTC1 gene and the methylation levels of TMTC1-1,TMTC1-2 and TMTC1-3 fragments were significantly lower than the control group,and there was no significant difference between the two groups in the male sample.DNA methylation levels of 32 Cp G sites in the overall sample were significantly different between case and control groups,no DNA methylation levels of all Cp G sites in the male sample,and DNA methylation levels of 14 Cp G sites in the female sample were significantly different between cases and controls.A significant correlation was observed between the promoter methylation level of TMTC1 gene and CHO and LDL-C.WBC levels were significantly higher in the case group than in the controls;HGB,creatinine,urea,CHO,HDL-C and LDL-C levels were significantly lower than in the control group.WBC,uric acid and BMI,low literacy,unmarried and smoking may increase the risk of schizophrenia.3.The m RNA and protein expression levels of TMTC1 gene in the peripheral blood of schizophrenia patients were significantly higher than those in the healthy control population.Conclusion（s）:1.The me QTL locus rs12304225 of the TMTC1 gene may be a schizophrenia risk locus.2.The methylation level in the promoter region of the TMTC1 gene is associated with schizophrenia and is sex-specific,and women are more likely to develop schizophrenia.WBC,uric acid level and BMI,low education level,unmarried and smoking may be risk factors for schizophrenia.3.The m RNA and protein expression of TMTC1 gene in the peripheral blood of schizophrenia patients was significantly higher than that in the healthy control population. |
