ABSTRACT: Child maltreatment (CM) is associated with adverse physical, psychological, and neurodevelopmental outcomes later in life. Epigenetic modifications, particularly DNA methylation, have been proposed as potential mechanisms underlying these long-term effects. To identify robust CM-associated methylation signatures, we conducted epigenome-wide analyses across three independent cohorts: judicial autopsy cases (CM:11, Controls:7), toddlers shortly after social intervention (CM:36, Controls:49), and adolescents who underwent brain MRI (CM:61, Controls:62). Each cohort was analyzed separately, followed by a meta-analysis to identify common methylation sites associated with CM exposure. The meta-analysis identified four significant CpG sites located within the ATE1, SERPINB9P1, CHST11, and FOXP1 genes. Among these, methylation of FOXP1 was consistently associated with structural brain alterations, including increased gray matter volume (GMV) in the orbitofrontal cortex (OFrC) and middle/posterior cingulate gyrus (MPCG), and decreased GMV in the occipital fusiform gyrus (OFuG). These brain regions are implicated in emotional regulation, memory retrieval, and social cognition, suggesting a potential neurobiological mechanism linking CM to later psychopathology. Furthermore, methylation risk scores (MRS) derived from these four CpGs successfully discriminated individuals who experienced early-life adversity in an independent validation dataset, achieving an area under the receiver operating characteristic curve (AUC) of 0.672, highlighting their potential utility as biomarkers. Gene ontology and pathway analyses revealed enrichment of cholinergic and glutamatergic synaptic transmission pathways, supporting their involvement in traumatic memory formation. Our findings provide novel insights into the epigenetic mechanisms underlying CM and identify potential biomarkers for early detection, prevention, and therapeutic intervention, ultimately contributing to breaking the intergenerational cycle of maltreatment.
