Cardiff University researchers have identified new mutations in a gene that provides novel insights into the biological causes of schizophrenia.

Dr Elliott Rees, a research fellow at the Medical Research Council Centre for Neuropsychiatric Genetics and Genomics, analysed genetic data from 3,444 families affected by schizophrenia, in the largest study of its kind.

Scientists have already pinpointed specific genes that can predispose people to neuropsychiatric disorders, such as autism and developmental delay.

The study looked specifically at those high-risk genes, and found that one in particular, SLC6A1, had significantly more new mutations than expected by chance.

The mutations were very rare, found in around three in 3,000 individuals diagnosed with schizophrenia.

The importance lies not in how common the mutations are but the area of biology highlighted, namely one of the main chemical transmitters of the central nervous system, known as GABA. This points towards alterations in how brain cells communicate as a potential cause of schizophrenia.

Also, these mutations appear to substantially increase the risk of developing the condition, suggesting that treatments developed to target this system could potentially have large therapeutic effects.

The findings, published in the journal Nature Neuroscience, offer further insight into the underlying causes of schizophrenia, a frequently severe mental health condition that can cause hallucinations and delusions.

The ultimate goal is to develop new therapies for the condition, which affects about 1% of the world’s population – and 600,000 people in the UK.

Dr Rees, who has been working on the study for three years, said:

“This work increases our understanding of the biological causes of this condition, which we hope will lead to the development of new and more effective treatments – because identifying the key genes involved provides molecular targets for the development of novel drugs.”

Professor Sir Michael Owen, former director of the MRC Centre and one of the study’s authors, said:

“As well as implicating a specific gene, SLC6A1, for the first time in schizophrenia, our findings suggest that new mutations in genes that are important in brain development can be a major factor in some cases, and that these mutations can also increase the risk of other disorders such as autism and developmental delay.

“As well as understanding how the mutations impact on brain function, it will be important to understand what factors modify their effects as these may also be possible targets for new treatments.”

The world-leading MRC Centre has been at the forefront of understanding how biology and genetics interact in a range of neuropsychiatric conditions for 10 years.

Key research includes identifying genetic risk factors for ADHD, Alzheimer’s disease, schizophrenia and depression.