Paternal transmission of early life traumatization through epigenetics: Do fathers play a role?

Traumatizing events are known to have consequences for the victim which may lead to the development of several well-known mental disorders. Recent research has shown that traumatic events may affect not only the victims' lives, but also that of their progeny. It is generally accepted that this transmission of trauma occurs through parental behavior; however as has been recently discovered, the effects of trauma may also be inherited due to induced alterations in gene expression. These changes, so called epigenetic modifications, illuminate the interaction between genes and the environment. In contrast to mutations, epigenetic alterations do not change the DNA code, but rather modify the DNA structure, thus being capable of regulating gene expression and in turn making it possible for an individual to genetically respond to environmental changes. There are four possible epigenetic mechanisms: paramutation, DNA methylation, posttranslational modification of histones, and non-coding RNA. All of these mechanisms can be found both in somatic cells and in germ cells, leading to the putative transmission of alterations upon fertilization. To date, little is known regarding the epigenetic inheritance of trauma in humans. In this review, we elucidate the hypothesis that males may transmit biological correlates of traumatization through the germline to their offspring. This model of epigenetic inheritance has been supported by some evidence from animal studies. Overall, by considering findings on the epigenetic inheritance of traumatizing events in other mammals as well as findings on epigenetic transmission of acquired traits in humans, it should be possible through future research to confirm the transmission of traumatic effects in humans. By doing so, new possibilities of trauma treatment through modulation of epigenetic pathways might arise.