Genes In Brains Of Suicide Victims Marked By Child Abuse

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Main Category: Genetics
Also Included In: Psychology / Psychiatry;  Neurology / Neuroscience;  Mental Health
Article Date: 08 May 2008 - 0:00 PDT

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A study published in the open-access journal PLoS One demonstrates how environment affected the genes in brains of suicide victims. The researchers, led by Moshe Szyfa (Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec), found real differences between brains of men who committed suicide and the brains of men who did not.

Even though the genetic sequence was the same in the suicide and non-suicide brains, Szyfa and colleagues discovered that epigenetic markings were different. That is, the researchers noted a chemical coating on genes that was influenced by environmental factors. In this unique study, Szyf and his fellow researchers - all notable for previous work in epigenetics - studied the DNA of male suicide victims from Quebec. The 13 people who committed suicide all had been victims of child abuse.

"It's possible the changes in epigenetic markers were caused by the exposure to childhood abuse, although in humans it's difficult to establish causality between early childhood and epigenetic markers, in the way we have established this in animal subjects," said Szyf. "The big remaining questions are whether scientists could detect similar changes in blood DNA - which could lead to diagnostic tests - and whether we could design interventions to erase these differences in epigenetic markings"

Epigenetics is a field that focuses on the changes in gene functions that do not require changes in DNA sequences. The DNA that we inherit from our parents remains constant during our lives and is located identically in every part of our bodies. However, during the gestational period (pregnancy), a chemical coating named DNA methylation creates marks in the genes in our DNA. Throughout our early life, the marks are relatively sensitive to and can be affected by our environment. These epigenetic marks punctuate the DNA and instruct it as to when and where to express the correct genes.

To investigate the marks, the researchers analyzed a set of genes that code for rRNA - the main component of the cell's protein-manufacturing ribosomes. The creation of protein is crucial for learning, memory, building new neural connections, and decision-making behavior. The cell's rRNA is relevant to this study because it can be regulated epigenetically.

"Our data are merely consistent with the hypothesis that early life events can alter the epigenetic status of genes that mediate neural functions, and thus contribute to individual differences in the risk for suicide," conclude the authors.

Promoter-Wide Hypermethylation of the Ribosomal RNA Gene Promoter in the Suicide Brain
McGowan PO, Sasaki A, Huang TCT, Unterberger A, Suderman M, et al.
PLoS ONE (2008). 3(5): e2085.
doi:10.1371/journal.pone.0002085
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About PLoS ONE

PLoS ONE is the first journal of primary research from all areas of science to employ both pre- and post-publication peer review to maximize the impact of every report it publishes. PLoS ONE is published by the Public Library of Science (PLoS), the open-access publisher whose goal is to make the world's scientific and medical literature a public resource.

About the Public Library of Science

The Public Library of Science (PLoS) is a non-profit organization of scientists and physicians committed to making the world's scientific and medical literature a freely available public resource. For more information, visit http://www.plos.org

Written by: Peter M Crosta
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