COMT Val 158 Met polymorphism protects the impact of a mother's history of childhood trauma on emotional and behavioral problems in preschool children

Childhood trauma has a well-established negative impact for mental health outcomes across the lifespan. Accumulating evidence now suggests that offspring's mental health problems can also be a consequence of intergenerational trauma transmission. A child's genetic background emerges as an important target in this outcome. This study aims to investigate the interactive effect of maternal childhood trauma and child COMT Val 158 Met polymorphism (rs4680) on offspring emotional/behavioral problems from a dyad of a population-based cohort that follow adolescent pregnant women and their children at age 4-5 and 11 years old. The behavior problems of 310 children were assessed using the Child Behavior Checklist (CBCL) instrument, and maternal trauma was assessed with the Child Trauma Questionnaire (CTQ) between the 20º to 22º gestational weeks. Regarding our results there was no direct association between the Val 158 Met polymorphism with emotional/behavioral problems in the children (p>0.05). However, we noted that maternal childhood trauma modified the effect of the Val 158 Met polymorphism on externalizing and total problems susceptibility. Children carrying the Val/Met genotype whose mothers have been exposed to childhood trauma are less likely to develop externalizing (p=0.020) and total problems (p=0.041) when compared with children homozygous (Val/Val and Met/Met). This association was maintained after adjustment for sex, age, and skin color. Thus, our findings reinforce evidence on the intergenerational impact of maternal trauma on emotional/behavioral problems and show that this risk is influenced by the genetic background of the individual, varying according to COMT genotype, which confers a protective character for development of externalizing and total problems.