Researchers have uncovered evidence of a new gene that appears to increase the risk of developing schizophrenia, a disorder characterized by distorted thinking, hallucinations and a reduced ability to feel normal emotions.
The scientists utilized a cutting-edge technology called whole genome association (WGA) to search the entire human genome in 178 patients with schizophrenia and 144 healthy individuals.
WGA technology was used to examine over 500,000 genetic markers in each individual, the largest number of such markers examined to date, and the first published study to utilize WGA technology in a psychiatric illness. Previous studies have been much more limited in scope, often incorporating less than 10 markers.
The study results are scheduled to be published online in Molecular Psychiatry, which can be accessed at http://www.nature.com/mp/journal/vaop/ncurrent/index.html.
Of the 500,000 genetic markers, the researchers found that the most significant link with schizophrenia came from a marker located in a chromosomal region called the pseudoautosomal region 1 (PAR1), which is on both the X and Y chromosomes.
The marker was located adjacent to two genes, CSF2RA and IL3RA, which previously were thought to play a role in inflammation and autoimmune disorders. Those two genes produce receptors for two cytokines, GM-CSF and interleukin-3. Cytokines are involved in the body’s response to infection, and may play a role in the brain’s response to injury.
By then examining the DNA sequence of those genes in a separate group of patients with schizophrenia and healthy individuals, the research team – working in conjunction with PGx Health in New Haven, CT — observed multiple gene abnormalities in patients with schizophrenia that were not found, or were found much less commonly, in healthy individuals.
“WGA technology allowed us to shine a light across virtually the entire genome, rather than looking at just one gene at a time,” said Todd Lencz, PhD, the first author of the study, and an investigator at Zucker Hillside and The Feinstein Institute. “Using WGA, we found genes that had not been previously considered in studies of schizophrenia.” Dr. Lencz added that “the critical next step is confirming these results in independent datasets.”
Anil Malhotra, MD, also of Zucker Hillside and The Feinstein, and senior investigator of the study, noted: “If these results are confirmed, they could open up new avenues for research in schizophrenia and severe mental illness. A role for cytokines could help explain why prenatal exposure to viruses is a risk factor for schizophrenia, thus providing a bridge between genetic risk and environmental exposures.”