Researchers Discover a Gene for Persecutory Delusion
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It’s the feeling that everyone is trying to harm you and that you are being persecuted - by friends, co-workers, and even by the secret service. You feel that you are constantly under surveillance. Everywhere small cameras are hidden: in the kitchen cupboard, in the lamp on the night table, in the whole city.
People who think like this or have similar feelings suffer from persecutory delusion.
People who think like this or have similar feelings suffer from persecutory delusion.
Persecutory delusion is one of the typical symptoms of schizophrenia. But this symptom also occurs in other psychiatric diseases, for instance in manic-depressive illness, also called bipolar disorder. Characteristic for the clinical picture of bipolar disorder is the frequent change in mood between the two poles "depressive" and "overly high".
Schizophrenic disorders are characterized by disturbances and changes of thinking, feeling, acting and experiencing the self. The most prominent features of schizophrenic disorders are delusions and fallacious perceptions (hallucinations).
Schizophrenic disorders are characterized by disturbances and changes of thinking, feeling, acting and experiencing the self. The most prominent features of schizophrenic disorders are delusions and fallacious perceptions (hallucinations).
Now scientists in the National Genome Research Network have discovered a risk gene that appears in both disease pictures. Researchers in Mannheim and Bonn found a mutation of the gene 72 in the DNA of several schizophrenia patients and several bipolar patients. The patients in which the NGFN found the gene had one thing in common: They suffered from persecutory delusion.
"There is therefore a relationship between the variant of the G72 gene and persecutory delusion," explains Thomas G. Schulze of the Central Institute for Mental Health in Mannheim. "The fact that we have found this gene variant both in patients with schizophrenia and in patients with bipolar disorder shows that both illnesses can have the same causes on the genetic level."
Even if schizophrenia, manic-depressive disorder, depression and anxiety disorders constitute different illnesses according to current doctrine: The findings of the NGFN scientists substantiate the hypothesis that there is, in part, very extensive symptom overlap between bipolar disorder and schizophrenia, which is based on the disease genes they have in common.
"There is therefore a relationship between the variant of the G72 gene and persecutory delusion," explains Thomas G. Schulze of the Central Institute for Mental Health in Mannheim. "The fact that we have found this gene variant both in patients with schizophrenia and in patients with bipolar disorder shows that both illnesses can have the same causes on the genetic level."
Even if schizophrenia, manic-depressive disorder, depression and anxiety disorders constitute different illnesses according to current doctrine: The findings of the NGFN scientists substantiate the hypothesis that there is, in part, very extensive symptom overlap between bipolar disorder and schizophrenia, which is based on the disease genes they have in common.
"This study confirms for the first time what we psychiatrists have known from our clinical experience for a long time, namely, that patients cannot be pressed into a diagnostic scheme that differentiates sharply between illnesses," says Marcella Rietschel, professor in Mannheim.
The function of the G72 risk gene is still unknown to a great extent. Interestingly, it only occurs in humans and primates. The gene contains the blueprint for a protein that binds to another protein, specifically to "D-amino acid oxidase". This protein is involved in the production of certain messenger substances and thus influences signaling transduction in the brain. It is probably only due to this binding that the "D-amino acid oxidase" becomes able to function.
In the pathogenesis of mental illnesses such as schizophrenia or manic-depressive disorder, what role does the protein play that activates D-amino acid oxidase? To find this out, studies on mouse models are currently being carried out in whose genome a DNA segment of the human G72 gene has been inserted. Using the mouse model, researchers can find out in which regions of the brain the protein at issue is active, how it functions and how pharmaceutical substances work that specifically intervene in the disease mechanism of D-amino acid oxidase.
Website of scientists involved in this NGFN project
Central Institute of Mental Health
University Bonn
Life & Brain GmbH
In the pathogenesis of mental illnesses such as schizophrenia or manic-depressive disorder, what role does the protein play that activates D-amino acid oxidase? To find this out, studies on mouse models are currently being carried out in whose genome a DNA segment of the human G72 gene has been inserted. Using the mouse model, researchers can find out in which regions of the brain the protein at issue is active, how it functions and how pharmaceutical substances work that specifically intervene in the disease mechanism of D-amino acid oxidase.
Website of scientists involved in this NGFN projectCentral Institute of Mental Health
University Bonn
Life & Brain GmbH
