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Test score estimates schizophrenia risk

INDIANA U. (US) — Researchers have created a prototype test to predict whether a person is at a higher or lower risk of schizophrenia.

The test, which is based on analysis of a specific set of genes, generates a score that indicates risk level.

“For first time we have a comprehensive list of the genes that have the best evidence for involvement in schizophrenia,” says principal investigator Alexander B. Niculescu, associate professor of psychiatry and medical neuroscience at Indiana University.

When the test is refined, it could provide guidance to caregivers and health care professionals about young people in families with a history of the disease, prompting early intervention and treatment when behavioral symptoms of schizophrenia occurred among those at higher risk, says Niculescu, who is also staff psychiatrist and investigator at the Richard L. Roudebush Veterans Affairs Medical Center.


He stresses that a score indicating a higher risk of schizophrenia “doesn’t determine your destiny. It just means that your neuronal connectivity is different, which could make you more creative, or more prone to illness.”

“It’s all on a continuum; these genetic variants are present throughout the population. If you have too many of them, in the wrong combination, in an environment where you are exposed to stress, alcohol and drugs, and so on, that can lead to the development of the clinical illness,” he adds.

The prototype test was able to predict whether a person was at a higher or lower risk of schizophrenia in about two-thirds of cases, according to a report published in the journal Molecular Psychiatry.

To identify and prioritize the genes, researchers combined data from several different types of studies. These included genome-wide association studies, gene expression data derived from human tissue samples, genetic linkage studies, genetic evidence from animal models, and other work.

This approach, called convergent functional genomics, has been pioneered by Niculescu and colleagues, and relies on multiple independent lines of evidence to implicate genes in clinical disorders.

The authors noted that the results were stronger when analyses were performed using gene-level data, rather than analyses based on individual mutations—called single nucleotide polymorphisms, or SNPs—in those genes.

Multiple different SNPs can spark a particular gene’s role in the development of schizophrenia, so evidence for the genes, and the biological mechanisms in which they play a role, was much stronger from study to study than was the evidence for individual SNPs.

Past research looking at individual mutations was difficult to replicate from study to study, says Niculescu. The new study, however, indicates that much of the research done in recent years has in fact produced consistent results at a gene and biological pathway level.

“There is a lot more reproducibility and concordance in the field than people realized,” he notes.

“Finally now, by better understanding the genetic and biological basis of the illness, we can develop better tests for it, as well as better treatments. The future of medicine is not just treatment but prevention, so we hope this work will move things in the right direction.”

Collaborators include researchers from Trinity College, UC San Diego, the Scripps Research Institute, Washington DC VA Medical Center, and Cardiff University.

Support for the research was provided by a National Institutes of Health and a Veterans Administration Merit Award.

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