Schizophrenia not always inherited – Genetic links found

By Dr. Ananya Mandal, MDAug 8 2011

Researchers have found that more than half the cases of non-hereditary or sporadic schizophrenia are caused by “new” protein-altering gene mutations. These 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.

For the study the team of researchers examined the genomes of genetically isolated Afrikaner families of European descent in South Africa. The 225 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.

First author Bin Xu, an assistant professor of clinical neurobiology at Columbia University Medical Center said, “Identification of these damaging de novo mutations has fundamentally transformed our understanding of the genetic basis of schizophrenia.” “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,” she said.

Schizophrenia is quite common, affecting one in every 100 people during their lifetime. Genes are involved, a tenth of people with schizophrenia also have a parent with the condition.

The charity Rethink Mental Illness said research on mental illnesses lagged behind that of other conditions. Its chief executive, Paul Jenkins, said, “We welcome any research which helps develop a better insight of the causes of schizophrenia and ultimately brings us closer to finding new ways of preventing or treating the condition in the future.”