A Systematic Review of the Possibility of Determining Age Based on DNA Methylation of the ELOVL2 Gene in Human Samples

Background: In forensic medicine, predicting the age of a victim or suspect can be a clue to solving a crime. Epigenetics has recently played a vital role in age prediction in forensic medicine. Cytosine methylation at cytosine and guanine separated by phosphate (CpG) sites is well recognized as a novel epigenetic marker for age estimation. This study aimed to summarize the information obtained from previous studies to determine age by evaluating DNA methylation in the ELOVL2 gene. Methods: In this systematic review, all related articles published between 2012 and 2022 were extracted by searching reputable scientific databases, such as ISI Web of Science, Science Direct, PubMed, and Scopus. After selecting the appropriate articles, the full text of the articles was prepared and fully evaluated by the researchers. The protocol of this study was carried out based on the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement. Results: Out of 307 articles, 5 articles were eligible for review according to the study protocol. The strongest correlation between DNA methylation and age was observed at sites 11044644 and 11044634 on chromosome 6 in the living cases. The relationship between the chronological age and the age calculated through DNA methylation was above 90% with an approximate error ranging from 7.5 to 10.4. However, the relationship between the chronological age and the age calculated through DNA methylation was above 90% in the multivariate analysis of sites 11044624 and 11044634 on chromosome 6. In this case, the calculation error reached approximately 6.9 years. Hence, considering a combination of multiple cytosine and guanine separated by phosphate (CpG) sites improves the calculation accuracy and reduces the error percentage. The relationships between DNA methylation and the age at sites 11044880 and 11044640 on chromosome 6 were significantly less reported in the blood samples taken from the dead and in those taken from the living (nearly 64%–78.5%). Conclusion: The results of this study indicated that DNA methylation in the ELOVL2 gene could help predict a person’s biological age.