Maternal epigenetic index links early neglect to later neglectful care and other psychopathological, cognitive, and bonding effects.

Background: Past experiences of maltreatment and life adversity induce DNA methylation changes in adults, but less is known about their impact on mothers' maladaptive neglectful parenting and its negative effects. We performed an epigenome-wide association study to investigate the role of DNA methylation levels in mothers with neglectful care, who were exposed to childhood maltreatment and neglect, and their current negative effects. Saliva DNA methylation was determined with the Illumina Human Methylation EPIC BeadChip v1. The individual epigenome was the input to a machine learning algorithm for trajectory inference, which assigned a specific state to each mother in the progression from healthy controls to the extreme neglect condition. A compound epigenetic maternal neglect score (EMN) was derived from 138 mothers (n = 51 in the neglectful group; n = 87 in the control non-neglectful group) having young children. Differential methylation between groups was utilized to derive the EMNs adjusted for education level, age, experimental variables, and blood cell types in saliva samples.

Results: Structural equation modeling: X² (29) = 37.81; p = 0.127; RMSEA = 0.048, confirmed that EMNs link their early experience of physical neglect to current reports of psychopathological symptoms, lower cognitive status, and observed poor mother-child emotional availability. A third of the genes annotated to the CpGs that affect EMNs are related to cognitive impairment and neurodegenerative and psychopathological disorders.

Conclusions: EMNs are a novel index to assess the contribution of DNA methylations as a neglected girl to later neglectful caregiving behavior and other negative effects. The evidence provided expands the possibilities for earlier interventions on the neglect condition to prevent and ameliorate the direct or indirect epigenetic impact of maternal adversities on mother-child care, helping to break the cycle of maltreatment.