An uncommon variation of a gene called Nogo, when inherited from both parents, increases the risk of developing schizophrenia, says a study to be published in Molecular Brain Research Nov. 15. Previous findings about other risk genes for the disease were restricted to specific ethnic groups.
"Finding a risk gene in the general population - the first finding of this type internationally - opens the door to discovering new and related risk genes. Now scientists will know where to look for related genes," says pharmacology and psychiatry professor Philip Seeman. "This will help in diagnosis and potentially in the design of new medications for treatment of this terrible disease," adds Seeman who worked on the study with psychiatry professor Teresa Tallerico, lead author and pharmacology graduate student Gabriela Novak and undergraduate student David Kim.
The study shows that one in five people with schizophrenia has this risk gene. Researchers found that 17 of 81 individuals with schizophrenia - 21 per cent - had inherited the uncommon Nogo variant gene from both parents. In a control group of individuals without schizophrenia, only three per cent had inherited the gene from both parents. People can inherit the variant Nogo gene from just one parent but there's a schizophrenia risk only when this gene is inherited from both parents. The gene does not suggest a diagnosis for schizophrenia but rather an increased predisposition to the illness.
One of the Nogo gene's functions is to produce proteins that inhibit the growth of nerve endings in the brain. Unlike the common form of Nogo, the variant gene has three extra chemical bases, known as CAA, in a region of the gene that regulates protein production. The researchers found that activity of the Nogo genes was higher in the post-mortem brain samples of individuals with schizophrenia
Contact: Jessica Whiteside
University of Toronto