Correlation Between The Methylation Of NPTX2 Gene And Age Estimation

Objective:To investigate the relationship of age and the methylation of CpG loci which is in the neuronal pentraxin Ⅱ (NPTX2) gene’s promoter region.Methods:Genomic DNA was extracted from 200 cases of peripheral blood samples of living, and then modified by methylation modification kit. Single locus of The NPTX2 gene promoter methylation status was detected by the methylation specific-PCR (MSP) method, and its relationship with gender, age was analyzed.60 samples of three age groups were selected. Methylation specific-high resolution melting curve (MS-HRM) was used to detect the relationship between multiple locus of its promoter methylation and age.Results:In the detection of MSP, age and sex of each sample were taken as independent variables while whether having methylation was taken as dependent variable. Binary logistic regression analysis showed that statistical significance was not found between whether having methylation and gender factor (P= 0.843), suggesting that gender does not affect NPTX2 gene methylation; and statistical significances were found between whether having methylation and age factor (P= 0.000), suggesting that age factors significantly influences the gene methylation. Taking five-year-old as an age group, linear regression analysis revealed that there were linear relationship among male (P= 0.001), female (P= 0.000) and the overall (P= 0.000), indicating that methylation rate is linearly increased with the increase of age. MS-HRM assay showed different methylation level in each age group, the level of methylation above 10% for group 1 to 5 years old 40%, group 31 to 35 years old 50%, group 61 to 65 years old 65%.Conclusion:The methylation rate of NPTX2 gene promoter increased with age. Further research may establish a regression model for age estimation.