Scientists have discovered a genetic variant that substantially increases the risk for developing schizophrenia.
The study associates a deletion on chromosome 3 with increased incidence of schizophrenia.
Schizophrenia is a psychiatric illness, which is characterized by delusions, hallucinations, and disorganized thinking.
A team of researchers led by Stephen Warren, from Emory University studied the genetics of schizophrenia by analyzing the prevalence of copy number variants (CNVs) in schizophrenic patients.
CNVs are changes in the number of copies of DNA segments throughout the human genome. The researchers began by looking at Ashkenazi Jewish subjects already under study by collaborating scientist Ann E. Pulver, Sc.D. and her team at Johns Hopkins University. The Emory group found an excess of large, rare CNVs in these schizophrenic cases compared to controls.
Combining their analysis with those of previous CNV studies of schizophrenic patients, Warren and his colleagues identify a CNV, specifically, a deletion at 3q29, that associates with schizophrenia with an odds ratio (a measure of effect size) of 16.98.
"This odds ratio rivals that of any genome-wide association study of schizophrenia and suggests that the 3q29 deletion confers a significant risk for this severe psychiatric phenotype," said Warren.
An odds ratio of 17 means someone with this deletion is 17 times more likely to develop schizophrenia than someone without the deletion.
This research also highlights candidate genes contained within the deletion that may also be associated with schizophrenia.
The study has been published by Cell Press on August 5th in the American Journal of Human Genetics.