SUNDAY, Aug. 7, 2011 (HealthDay News) -- More than half the cases of non-hereditary -- or sporadic -- schizophrenia are caused by "new" protein-altering gene mutations, researchers have found.
These gene mutations, called "de novo" mutations, are new genetic errors that appear in patients but not in either of their parents, the researchers explained in the report published in the Aug. 7 online edition of the journal Nature Genetics.
In the study, the investigators examined the genomes of genetically isolated Afrikaner families of European descent in South Africa. The participants included patients with schizophrenia and their families, and healthy people in control groups.
The researchers identified 40 mutations, all in different genes and most of them protein-altering, that were associated with sporadic schizophrenia.
The findings could point the way to finding more mutations, perhaps hundreds, that contribute to schizophrenia, the study authors said.
"Identification of these damaging de novo mutations has fundamentally transformed our understanding of the genetic basis of schizophrenia," first author Bin Xu, an assistant professor of clinical neurobiology at Columbia University Medical Center, said in a medical center news release.
"The fact that the mutations are all from different genes is particularly fascinating," team co-leader Dr. Maria Karayiorgou, a psychiatry professor at the medical center, said in the release. "It suggests that many more mutations than we suspected may contribute to schizophrenia. This is probably because of the complexity of the neural circuits that are affected by the disease; many genes are needed for their development and function."
The U.S. National Institute of Mental Health has more about schizophrenia.