An international research collaboration has shed new light on how DNA sequence variation can influence gene activity in the developing human brain. The team, led by researchers at the University of Exeter Medical School, King’s College London and Cardiff University, conducted the first study of how genetic variation influences DNA methylation, an epigenetic modification that can have direct effects on gene expression and function, in the developing brain. They demonstrated the potential utility of such data for refining the genetic signals associated with diseases hypothesised to have a neurodevelopmental component, such as schizophrenia.
DNA methylation is a chemical modification to one of the four bases that make up our genetic code, controlling when and where genes are expressed. As with other epigenetic marks, it is known to be dynamic across the life course and modifiable by a number of factors, including the underlying genetic sequence. It represents one possible pathway between genetic variation and disease, with genetic differences altering the regulation of gene expression at specific points in development. In this study the authors found that genetic variants associated with schizophrenia were enriched for changes that impact upon DNA methylation in the developing brain. It is of particular interest that some of the genetic risk factors for schizophrenia are associated with differences in DNA methylation as early as the first and second trimester of life.
Professor Jonathan Mill, of the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King's College London and the University of Exeter Medical School, said: "This study builds on the tremendous advances in identifying the genetic risks for schizophrenia in the last couple of years. We have shown that genetic variation can have significant effects on gene regulation during brain development, with important implications for understanding the origins of schizophrenia and other disorders with a neurodevelopmental component."