Association between different parameters of child maltreatment and global DNA methylation

Exposure to early life adversities, as child maltreatment may disturb the whole biological development of a child resulting in different consequences. Among the main underlying mechanisms are epigenetics and DNA methylation. The aim of the study was to access the effects of various factors such as child maltreatment (single or multiple), duration, frequency and age of onset of abuse on DNA methylation. Subjects and methods: 90 children (55 males, 35 females) aged 12-18 years were recruited from adolescent psychiatric outpatient clinics at Al-Hadara University Hospital in Alexandria, Egypt. A Childhood Trauma Questionnaire was used to take the history of child maltreatment. Global DNA methylation was determined by MethylFlash methylated DNA quantification colorimetric kit. Results: Regarding DNA methylation, there was a statistically significant hypomethylation was detected among those who reported exposure to more than one type of child maltreatment than those who reported no exposure or exposure to only one type. Significant difference was also detected between children who were exposed at the age of nine or less and those above 9 years. Moreover, a significant association was found between the duration and frequency of maltreatment in the prediction of DNA methylation. Conclusion: global DNA hypomethylation can be used as a marker to detect exposure to multiple types of child maltreatment. However, it is not about the early child maltreatment alone, but the accumulation of abuse over time and higher frequency of exposure to child maltreatment that causes more global DNA hypomethylation.