Studies into schizophrenia are revealing new insights into the genetic and environmental influences on the disease.
Scientists have previously found that genetic factors account for about 50% of the risk of developing schizophrenia, leaving the other 50% to external or environmental factors, the effects of which may be mediated via epigenetic mechanisms.
A study by a team at the John Hopkins University School of Medicine suggests that someone who carries specific genetic risk factors and also experiences certain kinds of stress early in life may be more likely to develop schizophrenia. The presence of variants in two genes (DISC1 and NKCC1) combined with early stress can increase overall disease risk by nearly one and half times.
Meanwhile, researchers at the Karolinska Instituet in Sweden have identified epigenetic changes in schizophrenic individuals; DNA from white blood cells showed methylation levels substantially lower than normal. They also found that the degree of methylation is related to age of disease onset and the severity of the disease, results that raise the possibility of developing a test for the disease.
Comment: Epigenetics may prove to be a key mediator for a whole range of environmentally influenced disease processes. The particular results outlined here are modest in their impact on disease risk, but could be of value in combination with other knowledge of specific genetic and environmental risk factors. How useful a predictive test for this condition would be is perhaps less clear.