Toxic childhood stress changes gene expression

Abuse early in childhood affects how certain genes are turned on or off, which may help explain why severely stressed children are at risk of psychological and physical problems, a recent study suggests.

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Researchers at the University of Wisconsin, Madison, measured DNA methylation, one of the biochemical processes that regulates gene activation and deactivation, in blood samples from 56 children aged between 11 and 14 years, half of whom had suffered physical abuse.

Abused children showed more methylation than children who hadn’t been maltreated at several sites on the glucocorticoid receptor NR3C1 gene, which plays a critical role in stress regulation. The affected sites include a part of the gene associated with nerve growth factor, which affects healthy brain development.

The study findings align with results of previous research in rodents, which showed that the glucocorticoid receptor gene influences the hypothalamic-pituitary-adrenal (HPA) axis. Disturbances in the HPA axis interfere with the regulation of emotional behavior and response to stress. The gene also has effects on the immune system that can increase vulnerability to illness.

Abused children are prone to develop mood and anxiety disorders and difficulty controlling their emotions. They are more likely to have elevated inflammation and antibody production, impaired immune function, and generally poorer health as they age than children who haven’t suffered abuse.

 The researchers note that animal research suggests toxic stress-driven gene changes may be reversible with intervention. Better understanding of the interaction between social experience and neurobiology could point to better ways to treat abused children.     

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