In a new study, Swedish researchers have identified epigenetic changes — known as DNA methylation — in the blood of patients with schizophrenia.
Epigenetics is an emerging field of study characterized by research on how the environment (or experiences) influences genetics.
Investigators were able to detect differences depending on how old the patients were when they developed the disease and whether they had been treated with various drugs. In the future, this new knowledge may be used to develop a simple test to diagnose patients with schizophrenia.
Schizophrenia is a relatively common chronic psychiatric disease affecting one percent of the population. The risk of developing schizophrenia increases if one has close family members who have had the disease. However, studies on identical twins (who share the same genetic background) show that only 50 percent of the disease risk can be explained by genetic factors.
This in turn suggests that environmental factors, which include epigenetic changes to the genome, account for the remaining 50 percent of the cause of the disease.
“Epigenetics involves small reversible chemical changes, for instance in the form of methyl groups that bind to certain DNA sequences in the genome, that can consequently modifythe function of the DNA.
“The research results we are now presenting suggest that epigenetic mechanisms are of great importance in mental illness. It is particularly interesting that these changes can also be linked to age at disease onset,” said Tomas Ekström, Ph.D.
In the current study, researchers determined the methylation levels in DNA in the white blood cells from individuals who suffer from schizophrenia are substantially lower than normal and that the degree of methylation is related to age of disease onset and the severity of the disease.
In the investigation, researchers also compared the degree of methylation in samples from patients who had been treated with various types of drugs. From this, scientists discovered that treatment with one type of antipsychotic drug could influence the levels of DNA methylation in the blood cells towards more normal levels.
In their article in FASEB Journal, the researchers note that at present there is no “biomarker” for schizophrenia that is suitable for clinical sampling.
Accordingly, an area of application for the new knowledge includes development of a simple test to diagnose schizophrenia, and to monitor how patients respond to the treatment they receive.
“The fact that DNA methylation in an ordinary blood sample can be used as a marker of the severity of schizophrenia opens up completely new opportunities. But follow-up studies are needed to clarify, for example, whether choice of treatment can be linked to this type of test,” said Martin Schalling, M.D., one of the researchers behind the study.
Source: Karolinska Institutet