Gene changes as a schizophrenia risk factor

Schizophrenia: Researchers discover genetic changes in those affected

01/12/2015

The causes of the development of schizophrenia are still largely unclear. Scientists at the University Hospital Heidelberg now have their own information „discovered in Schizophrenia patients ten previously unknown gene mutations (mutations)“, which are to be evaluated as risk factors for schizophrenic diseases. The results of the research team around first author Slavil Peykov were in the prestigious journal „Molecular Psychiatry“ published, according to the announcement of the University Hospital.

According to the researchers, about one percent of the world's population suffers from the mental disorder schizophrenia, the disease usually begins in early adulthood. The sufferers are during the episodes of the disease and occasionally beyond, barely able to independently manage their everyday lives, reports the university hospital on. They suffer from perceptual disorders such as delusions or hallucinations, often accompanied by language problems and depression. Overall, the symptoms of schizophrenia can be individually very different, which makes the diagnosis and treatment sometimes difficult.

Gene variants as risk factors for schizophrenia
About the exact causes and triggers of schizophrenia is according to the announcement of the University Hospital Heidelberg until today little is known. With their current study, the researchers around first author Dr. Slavil Peykov now discovered ten previously unknown gene alterations apparently related to the development of schizophrenia. „These ten gene variants are risk factors for a schizophrenic disorder“, emphasizes the Director of the Department of Molecular Human Genetics at the University Hospital Heidelberg, Prof. Dr. med. Gudrun Rappold. The affected gene provided the blueprint for a scaffold protein - the so-called SHANK2 protein - which plays a crucial role in signaling between nerve cells. Since the changes occurred exclusively in patients, but not in healthy controls, the researchers became aware of the ten previously unknown mutations.

Schizophrenia patients show more genetic changes
„Mutations that are not found in healthy people could have a direct impact on the disease“, explains Dr. Slavil Peykov. The researchers from Heidelberg, in collaboration with Professor Marcella Rietschel from the Department of Genetic Epidemiology at the Central Institute for Mental Health in Mannheim and Professor Markus Noethen from the Institute of Human Genetics at the University of Bonn, investigated the SHANK2 gene in the genome of 481 affected individuals and 659 healthy controls. Overall, schizophrenia patients had approximately twice as many genetic changes as people without mental illness, the University Hospital reports. Some of the gene variants are clear risk factors, but it is likely that the disease will not start until then, „if additional factors, such as certain environmental influences, are added“, explains the human geneticist Prof. Dr. med. Gudrun Rappold.

Changes of the same gene also in autism
Back in 2010, scientists had around the human geneticist Rappold „demonstrated various changes in the SHANK2 gene in patients with autistic disorder and mental retardation“, reports the University Hospital Heidelberg. Although the mutations found in schizophrenia would be in the same gene, they would differ significantly from the changes in autism. „Obviously, the exact nature of the change affects which neuropsychiatric disorder develops and how severe the symptoms are“, explains Rappold. So could „Changes in one and the same gene lead to very different neurobiological disorders such as autism and schizophrenia or mental retardation.“ What all these mutations have in common is that they affect, to varying degrees, the degree of cross-linking of certain areas of the nerve cells and thus the signal transmission between the nerve cells.

Benefits for the treatment of schizophrenia patients
Although the formation of further genetic schizophrenia risk factors does not explain the development of the disease. But you can „Knowing the genetic causes of this disease will help doctors in future to divide those affected into subgroups with similar disease progression and treat them more effectively at an early stage“, explains the human geneticist Rappold. For example, among the 481 patients, four unrelated individuals with exactly the same mutations would have been found. „With them, the disease began comparatively early and with similarly pronounced symptoms“, so the message from the University Hospital. Also, the search for the genetic background brings advantages in the development of new therapies with it. „If it is known which molecular processes in the brain are disturbed, scientists can more specifically explore new therapeutic approaches“, reports the University Hospital Heidelberg. (Fp)