Schizophrenia risk increases 10-fold with genetic mutation

Researchers from Trinity College in Dublin, Ireland, have identified a risk gene mutation for schizophrenia and bipolar disorder that increases chances of developing the conditions by more than 10-fold. The team says they found this mutation is inherited from a distant but common European ancestor.

The international team, led by Prof. Aiden Corvin at Trinity's School of Medicine, says identifying this genetic mutation provides the medical community with insight into potential risk mechanisms for these disorders, the cause of which is poorly understood.

Results of their study are published in the journal Human Molecular Genetics.

Although treatments are available for schizophrenia and bipolar disorder, and evidence is increasingly suggesting these disorders share common genetic risk factors, the team says response to treatments varies and knowledge of the underlying biology has mostly eluded scientists.

Bipolar disorder affects around 4% of the world's population, and schizophrenia impacts around 51 million people around the world (about 1% of the world's population), the team says.

For their research, the investigators analyzed blood samples from over 1,564 Irish people with schizophrenia and 1,748 controls who did not have the disorder. They looked for small structural differences in the genome where material is either duplicated or deleted.

First author of the study Dr. Derek Morris, from the National University of Ireland (NUI), Galway, explains that when replication of a genome takes place, there can be small "editing" problems known as mutations:

"This is how diversity happens in biology and is like a typo in a book; it happens rarely and the context will determine how the 'word,' or in our case a protein, is affected."

Carriers of genetic mutation share common European ancestor

Through their study, the researchers found five patients in which a gene - called Protein-Activated Kinase 7 (PAK7) - was duplicated. This duplication was not found in anyone in the control group, they note.