In the first study to explore the entire human genome for variations that may influence the development of schizophrenia, researchers have discovered two new sites of genetic variation that are closely associated with the disease.  “By implicating two previously unknown sites, this study triples the number of genomic areas definitely linked to schizophrenia,” said NIMH Director R Thomas Insel, M.D.

The genetic variations include both duplications and deletions of the genetic code.  These newly discovered DNA variations are not uncommon in the general population, but they are about 15% more prevalent among schizophrenic patients, says Pamela Sklar, MD, PhD, of Harvard University.  Sklar, also affiliated with the Stanley Center for Psychiatric Research, has published her multi-national research team’s findings online at the website for the journal, Nature.

Sklar’s International Schizophrenia Consortium, working from 11 research facilities around the world, explored the genomes of 3,391 European patients with schizophrenia and a control group of 3,181 individuals who did not have the disease.  Although the exact genetic details are still unknown, about 73% to 90% of all cases of the disease are thought to be genetic in origin.

The consortium discovered genetic variations in 13.1% of the patient cases but only in 10.4% of the control group, a difference considered statistically significant.  Most variations were 1.41 times more common in the test, or patient, group than in the control group and the most rare variations, those that occur just once, were 1.45 times more common in the test group than in the control group.

Even though the genetic variations are linked so closely to the development of schizophrenia, the exact mechanisms of the disease remain unknown.  It is clear, however, that the increased burden of the genetic variations increases the likelihood of developing the disease.  As more is known about the underlying factors that can lead to the disease, the medical community considers every new discovery as important to the development of better methods of diagnosis and treatment of the devastating disease, with the hope of preventing it someday.

Source: NIH