January 30, 2014. The first genomewide survey of methylation patterns in schizophrenia turns up 25 suspect regions, some of which include genes linked to hypoxia. Published online January 8 in JAMA Psychiatry, the study examines blood samples from 759 people with schizophrenia and 738 controls to find differences in the methyl groups that, when attached to a segment of DNA, suppress expression of nearby genes. Led by Edwin van den Oord at Virginia Commonwealth University in Richmond, the results suggest that methylation patterns found in blood could record past environmental insults and may serve as useful biomarkers for schizophrenia.
Some methylation patterns found in blood cells may mirror those in the brain, according to a second, smaller study published in Translational Psychiatry on January 7. A team led by Joanne Voisey at Queensland University of Technology, Brisbane, Australia, found that 99 genes that were differently methylated in brain samples from people with schizophrenia compared to controls were on the same list of genes previously singled out as differently methylated in blood samples.
Together, the results point to methylation patterns as a rich source for variation that may hold clues to how genes and environment combine to boost risk for schizophrenia. Researchers have seized upon epigenetics, either in the form of methylation or histone modification, because it offers a way for experience to alter what is produced by the genome. The cells in which the methylation patterns are studied, however, may matter. If patterns found in blood match those found in the brain, they might provide some causal insights into the disease process. If they are specific to blood, however, they may still be a useful biomarker from an easy to obtain source.