U of T scientists discover genetic changes that may contribute to schizophrenia

Scientists have discovered rare genetic changes linked to autism spectrum disorder (ASD) may also be responsible for one in 13 cases of schizophrenia.

In the first study of its kind, University of Toronto scientists at the Centre for Addiction and Mental Health (CAMH) and The Centre for Applied Genomics (TCAG) at The Hospital for Sick Children analyzed the DNA of 459 Canadian adults with schizophrenia to detect rare genetic changes.

“We found a significant number of large rare changes in the chromosome structure,” said Professor Anne Bassett, Canada Research Chair in Schizophrenia Genetics and Genomic Disorders at the University of Toronto and Director of CAMH’s Clinical Genetics Research Program.

“We expect that up to eight per cent of schizophrenia may be caused in part by such genetic changes — roughly one in every 13 people or 7.6 per cent of people with the illness.”

The research team also developed a systematic approach to the discovery and analysis of new, smaller rare genetic changes leading to schizophrenia, providing dozens of new leads for scientists studying the illness.

“We identified smaller changes in chromosome structure that may play an important role in schizophrenia — and that these often involve more than one gene in a single person with the illness,” said Bassett, who is also a Clinician Scientist in the Campbell Family Mental Health Research Institute.

“Moving forward, we will be able to study common pathways affected by these different genetic changes and examine how they affect brain development. The more we know about where the illness comes from, the more possibilities there will be for the development of new treatments,” Bassett said.

The research team also suggests that clinical DNA (genome-wide microarray) testing — the method researchers used to analyze patient DNA — may be useful in demystifying one of the most complex and stigmatized human diseases: schizophrenia.

“We have seen the success clinical microarray testing has had in making sense of ASD for families, and we think the same could be true for schizophrenia,” said Stephen Scherer, Director of University of Toronto’s McLaughlin Centre and TCAG.

The study is published in the current issue of Human Molecular Genetics, and was funded by the Canadian Institutes of Health Research (CIHR).