US researchers have identified several genes related to brain function that may increase the risk of developing schizophrenia, according to a new study published in the Proceedings of the National Academy of Sciences.
Scientists compared the whole genome of 1,735 people with schizophrenia with the genome of 3,485 healthy controls and found regions of variation in or near several genes, including in some genes involved in brain signalling and brain development.
'When we compared the genomes of patients with schizophrenia to those of healthy subjects, we found variations in genes that regulate brain functions, several of which are already known to be perturbed in patients with this disorder', said lead researcher Dr Hakon Hakonarson, director of the Center for Applied Genomics at The Children's Hospital of Philadelphia.
The variation found between the regions was due to copy number variants. A copy number variant is a large segment of DNA that is repeated, with the number of repeats differing between individuals due to deletions or duplications. The repeated segment may span an entire gene or a series of genes, thereby encompassing more genetic information than the single nucleotide changes analysed in most genetic studies.
Interestingly, some of the varying regions highlighted in this study have also been implicated in other mental disorders. In particular, one region of deletions found in this study was identified in an earlier study of autism spectrum disorders (also conducted by Dr Hakonarson).
'Although different brain regions may be affected in these different mental disorders, these overlaps suggest that there may be common features in their underlying pathogenesis. These genes affect synaptic function, so deletions or duplications in those genes may alter how brain circuits are formed', said Dr Hakonarson.
'Although much research remains to be done, detecting genes on specific pathways is a first step to identifying more specific targets for improved drug treatments', he added.