A gene that increases the risk of schizophrenia has recently been identified, and it may help scientists better understand how the mental illness occurs, a new study suggests.
The new schizophrenia risk gene, known as C4, was found after researchers had conducted studies in both mice and humans. There may be a link between C4 and the process of synaptic pruning or axon pruning – in which the connection between neurons are eliminated. In many mammals the synaptic pruning takes place between early childhood and the onset of puberty.
Researchers speculate that inappropriate or excessive synaptic pruning could cause schizophrenia. It would also explain why symptoms of schizophrenia usually appear during teen years. The new study may not only help scientists understand what causes schizophrenia, but also help develop a new treatment for schizophrenia in the future – provided that the results of the study hold true.
Beth Stevens, a neuroscientist and an assistant professor of neurology at Boston Children’s Hospital, said that scientists are currently far from having a treatment based on the new findings.
In the study – published Saturday (Jan. 27) in the journal Nature – researchers at the Broad Institute’s Stanley Center for Psychiatric Research at Harvard Medical School focused on a gene, called complement component 4 (or C4). This particular gene is known to play a role in the immune system.
To estimate how active the C4 genes are, researchers looked at their length and the variations of the genes in samples from post-mortem human brains. They then looked at data on the C4 gene in 36,000 people without schizophrenia and 28,800 people with schizophrenia, from twenty-two countries around the world. The researchers predicted the C4 gene activity using the genome data.
The findings showed that a person’s risk of developing schizophrenia increased when the activity levels of the C4 gene were higher. The experiments in mice also showed that more C4 activity led to more synapse loss during brain development, according to the research team. In any case, further research is needed to confirm the results.
Jonathan Sebat, chief of the Beyster Center for Molecular Genomics of Neuropsychiatric Diseases at the University of California, San Diego, said that the new findings are the first to show a connection between schizophrenia and synaptic loss. According to Sebat, medications that activate the part of the immune system in which the C4 gene is also plays a part are currently being developed.
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