SETD1A: Single gene increases risk of schizophrenia by 35 times

Scientists have discovered a possible cause for schizophrenia; a mutation in the SETD1A gene. Changes to this gene have been found to increase the risk of schizophrenia by 35 times, as well as a number of other neurological disorders.

The research published in Nature Neuroscience is the first to establish a link between a single gene and schizophrenia. Until now, scientists have struggled to find a cause for the condition which affects 300,000 people in the UK.

"We have a very limited understanding of how schizophrenia arises, and this has hampered attempts to develop new treatments," said Sir Mike Owen, researcher working on the study from Cardiff University. "Current drugs are only effective in alleviating some of the symptoms, can lead to troubling side effects, and are ineffective in a sizeable minority of cases. Defects in the SETD1A gene, may guide us towards new pathways that could be targets for therapeutic drugs in a larger number of cases."

Analysing the genomes of 15,000 people

The researchers analysed the genomes of 5,341 schizophrenia patients, as well as 9,343 volunteers that did not have the condition, from Finland, Sweden, and the UK.

They discovered that 10 of the schizophrenia patients showed a mutation to the SETD1A gene. There were zero mutations in the gene for the volunteers without schizophrenia.

The study also found a mutated SETD1A gene in six patients with other neurological conditions, including intellectual disability. The scientists say this could suggest a link between schizophrenia and other neurological disorders.

"The results were surprising," said Jeff Barret, lead author of the research. "Not only that we found such a high level of certainty that the SETD1A gene was involved, but also that the effects of the gene were so large. Psychiatric disorders are complex diseases involving many genes, and it is extremely difficult to find conclusive proof of the importance of a single gene. This is a really exciting finding for research into schizophrenia."

Aarno Palotie, a scientist working on the study, added: "To get this level of certainty about the involvement of rare genes requires a huge collaborative effort. Collaborations like this pave the way for large-scale analyses over the next couple of years that could really explain the genetic basis of schizophrenia."

The researchers built upon research from Columbia University, released in 2014. That study also identified a link to the SETD1A gene, but the study was carried out on 231 people with not enough genomes to conclusively say there is a link between schizophrenia and the mutated gene.