Role of Genotype in the Cycle of Violence in Maltreated Children

Abstract

We studied a large sample of male children from birth to adulthood to determine why some children who are maltreated grow up to develop antisocial behavior, whereas others do not. A functional polymorphism in the gene encoding the neurotransmitter-metabolizing enzyme monoamine oxidase A (MAOA) was found to moderate the effect of maltreatment. Maltreated children with a genotype conferring high levels of MAOA expression were less likely to develop antisocial problems. These findings may partly explain why not all victims of maltreatment grow up to victimize others, and they provide epidemiological evidence that genotypes can moderate children's sensitivity to environmental insults.

MAOA, maltreatment, and gene–environment interaction predicting children's mental health: new evidence and a meta-analysis

“…4,5 Thus far, efforts to replicate Caspi et al's 3 results have met with mixed results [6][7][8][9] indicating that, as yet, accepting the MAOA by maltreatment G Â E hypothesis would be premature without further investigation. The present study tested whether Caspi et al 3 original finding would replicate in a representative birth cohort sample of 7-year-old boys.…”

“…1,2 Many of these children develop behavioral and emotional difficulties, but many others are resilient and exhibit better functioning than predicted given their exposure to adversity. Recent findings 3 suggest that one explanation for variability in outcomes among maltreated individuals relates to a gene-environment interaction (G Â E) involving a functional polymorphism in the promoter region of the monoamine oxidase A (MAOA) gene. Specifically, maltreated children with the MAOA genotype conferring low levels of the MAOA enzyme more often developed conduct disorder, antisocial personality, and violent criminality in adulthood than maltreated children with a highactivity MAOA genotype.…”

“…Mental health outcomes as a consequence of childhood adversity have been measured at mean ages ranging from 13 to 26 years. 3,6,7 Whether the moderating effect of MAOA activity might be present in early life and closer in time to the stressful experience is unknown, yet this information is crucial for understanding the role that G Â E might play in developmental processes. The present study asked whether MAOA gene activity moderates the impact of maltreatment on mental health outcomes in childhood.…”

Applying upstream interventions for interpersonal violence prevention: An uphill struggle in low- to middle-income contexts

“…Nevertheless not all children exposed to adverse traumatic experiences become violent. A range of factors, including the presence of the MAOA genotype, other social support and IQ, serve to moderate the effects of maltreatment, and may provide protection [26].…”

The moderation by the serotonin transporter gene of environmental adversity in the aetiology of mental illness: review and methodological analysis

“…[4][5][6][7] In the last five years, G Â E involving specific gene polymorphisms has been identified in animals 8,9 and humans. [10][11][12][13] Encouragingly, replications 14,15 and a positive metaanalysis 16 indicate that measuring environment improves the reliability of genetic research.…”