Tuesday, 25 March 2014

Early Traumatization Modifies Genes

Abused children are highly at risk of getting distored by fear or temper as the impacting high stress can alter the regulation of their genes permanently. Scientists of the Max-Planck-Institute of psychiatry in Munich could document for the first time that some variations of the FKBP5-gene get epigenetically changed by early traumatization. In people with this genetic disposal, the trauma causes a permanent dysregulation of the system of stress hormones. As a consequence, people have to deal with a life long disability in coping with difficult situations, often leading to depression and anxiety disorders as grownups. Medical doctors and scientist expect from the actual findings methods of treatment adjusted to the respective patients but also enhanced public attention to protect children from trauma and its consequences.

Many human diseases result from an interaction of individual genes and influences from the environment. Traumatizing events especially during childhood are strong risk factors for the occurrence of psychiatric diseases later in life. Whether the early affecting stress actually becomes pathogenic, decisively depends on the relevant genetic endowments. 

So teamleader Elisabeth Binder of the Max-Planck-Institute of Psychiatry examined the genetic material of nearly 2 000 Afro-Americans who had been heavily traumatized as grownups or also as kids several times. One third of the trauma victims were ill and suffered from a posttraumatic stress disorder. The scientists wanted to clear up the mechanism of this gene-environment interaction by comparing the genetic sequences of diseased and not diseased trauma victims. The investigation showed that in fact the risk of posttraumatic stress disorder only increased with the heaviness of abuse only in persons with a specific genetic variation of the FKBP5-gene. FKPB5 determines how effectively the organism reacts to stress hormones and thus regulates the whole stress hormone system. 

In experiments with neurons, the Max-Planck scientists could further prove that the discovered FKBP5-variation actually makes a physiological difference for the respective people. Extreme stress and by this  high concentrations of stress hormones cause a so-called epigenetic modification: From the DNA, in this place a methyl group gets separated which significantly increases the activity of FKBP5. This permanent modification of DNA is mainly caused by traumatization at the age of childhood. With participants of the study who had been solely traumatized as grownups no disease associated demethylization of the FKBP5-gene could be found.

Torsten Klengel, scientist at the Max-Planck-Institute of Psychiatry explains the findings of the study as follows: “Traumas in infancy leave permanent traces in the DNA according to the genetic endowments. Epigenetic modifications in the FKBP5-gene enhance its efficiency. The presumed consequence is an ongoing deregulation of the stress hormone axis in these persons which can end up as a psychiatric disease. But it is decisive for the infant trauma victim that the stress induced epigenetic modifications can only appear when the victim has this specific DNA sequence.”

The study improves our understanding of psychiatric disorders as a consequence of the interaction of environmental and genetic factors. The findings will help to treat people individualized who have suffered from early traumatization and bear a significantly higher risk of disease.

Link to the source