Child abuse leaves epigenetic marks

http://www.genome.gov/27554258

By Roseanne Zhao, Ph.D.
July 3, 2013

Child abuse is a serious national and global problem that cuts across economic, racial and cultural lines. Each year, more than 1.25 million children are abused or neglected in the United States, with that number expanding to at least 40 million per year worldwide.

In addition to harming the immediate wellbeing of the child, maltreatment and extreme stress during childhood can impair early brain development and metabolic and immune system function, leading to chronic health problems. As a consequence, abused children are at increased risk for a wide range of physical health conditions including obesity, heart disease, and cancer, as well as psychiatric conditions such as depression, suicide, drug and alcohol abuse, high-risk behaviors and violence.

They are also more susceptible to developing post-traumatic stress disorder (PTSD)-a severe and debilitating stress-related psychiatric disorder-after experiencing other types of trauma later in life.

Part of the explanation is that child abuse can leave marks, not only physically and emotionally, but also in the form of epigenetic marks on a child's genes. Although these epigenetic marks do not cause mutations in the DNA itself, the chemical modifications-including DNA methylation-change gene expression by silencing (or activating) genes. This can alter fundamental biological processes and adversely affect health outcomes throughout life.

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Furthermore, the researchers found that epigenetic marks associated with gene expression changes were up to 12-fold higher in PTSD patients with a history of childhood abuse. This suggests that although all patients with PTSD may show similar symptoms, abused children who subsequently develop PTSD may experience a systematically and biologically different form of the disorder compared to those without childhood abuse.

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Since even small changes in DNA methylation signatures in child abuse can have long-term implications for fundamental biological processes and health, Dr. Mehta hopes their research will also increase public awareness and strengthen efforts to protect children from the consequences of childhood abuse and neglect.

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tags: child abuse