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Schizophrenia shares genetic links with autism, genome study shows

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schizophrenia gene brain autism dna geneitcSchizophrenia involves some of the same genetic variations as autism and attention deficit disorders, a new whole-genome study has confirmed.

Schizophrenia, which affects about 1.5 percent of the U.S. population, can result in a variety of symptoms that include disrupted thinking, hallucinations, delusions and abnormal speech. The disease is thought to have genetic links but usually does not manifest itself until adolescence or early adulthood.

In an effort to assess some of the common genetic variations that might underpin this fairly common but thorny mental illness, researchers sequenced DNA from 1,735 adults with schizophrenia and 3,485 healthy adults. Across the patients that had the disease, the researchers found many frequent variations related to copying or deleting genes, known as copy-number variations. And among the genes that were more likely affected by these changes in schizophrenic individuals were CACNA1B and DOC2A, which help make proteins for calcium signals that regulate neurotransmitters in the brain. Two other relatively common variations, in RET and RIT2, would likely impact brain development.

"These genes affect synaptic function, so deletions or duplications in those genes may alter how brain circuits are formed," Hakon Hakonarson, director of the Center for Applied Genomics at The Children’s Hospital of Philadelphia and coauthor of the new study, said in a prepared statement.

Previous research had turned up a few rare copy-number variations in schizophrenic patients, but they "explain only a small fraction of the genetic risk of this common complex disease," the researchers noted in their study, published online May 10 in Proceedings of the National Academy of Sciences. The new work confirmed higher rates of variations in some of the same networks disturbed in people with autism and attention deficit disorders.

"Although different brain regions may be affected in these different neuropsychiatric disorders, these overlaps suggest that there may be common features in their underlying pathogenesis," Hakonarson said.

Initial gene links for schizophrenia were reported nearly a decade ago, after researchers at Julius-Maximilian University of Würzburg in Germany found a common mutation on the 22nd chromosome in the protein-encoding gene WKL1. Since then, many studies have helped home in on triggers and therapies for the disease, but a cure for schizophrenia remains elusive.

"Much research remains to be done," Hakonarson said. But "detecting genes on specific pathways is a first step to identifying more specific targets for improved drug treatments."

Image courtesy of iStockphoto/mpabild

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  1. 1. jtdwyer 5:03 pm 05/10/2010

    That transcription errors, which may produce specific gene deletions or duplications, affecting different regions of the brain, occurs in the broad autism spectrum disorders, attention deficit disorder and schizophrenia hardly seems surprising or significant. I guess that other late onset condition affecting neural processing are also linked in this way.

    This weak link to transcription errors for genes involved in neurotransmitter regulation might have been guessed for any conditions that obviously affect neural processes. A more direct link might be indicated if the conditions had demonstrated cross inheritance capabilities.

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  2. 2. wildthing 7:29 pm 05/10/2010

    So proteins comtrol thoughts? Processing proteins and producing thoughts seem disimilar. You might be able to locate the type of thought occurring but I’m pretty sure the thought itself wilkl be a mystery. The way the thought affects the body and body affects the thought is different than the thought process itselfm it is just an interface.

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  3. 3. tryptofanatic 8:55 pm 05/10/2010

    Sure, proteins control thoughts. Thoughts are produced by changes in neuronal firing and wiring, both of these processes are controlled by proteins such as ion channels and receptors.

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  4. 4. Spin-oza 10:11 pm 05/10/2010

    I understand the link, both genetically and clinically between ASD & ADD… but the shizophrenia link seems a bit of a stretch and I doubt would be explanatory, versus an association or modifier of a shizoid personality.

    However, I think this much is crstal clear: the more we learn of the genetic-biochemical underpinnings of our brains, and hence our minds, the more interconnected and nuanced these (untidy) psychological "diseases" will become… and the more difficult it will be to define… what is… "normal".

    As for the skepticism regarding "proteins" and mental functioning… just take the relatively "simple" example of one of the most common causes of metal retardation, Fragile X. It produces a protein, FMRP, that if sufficiently compromised, leads to the disorder. The sole reason for it is a 3 nucleotide repeat in the FMR-1 gene… which in fact is "normally" repeated, to a point – but if repeated too many times, results in either a carrier state… or the disorder itself.

    See how the "mind" works?

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  5. 5. hawkeye 11:48 pm 05/10/2010

    I believe Spin-oza is right on. The more we learn, the more complex all these various relationships are going to become, to the point that "the more we learn, the less we know".

    And when I think about the schizophrenics I’ve encountered over the years, I’m not even sure that we have as yet accurately characterized schizophrenia as a single, broad category of disease.

    However, I have been struck by several clinical similarities between the more severe forms of ASD and catatonic schizophrenia. Time will tell, I guess.

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  6. 6. Bella Rossi 5:13 am 02/9/2012

    I have noticed also that families with one alot of the time will have the other within so many generations.

    Bella Rossi

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  7. 7. Bella Rossi 8:12 am 05/18/2013

    I think schizophrenia and autism are man made inventions.

    The two what we call disorders are simply clusters of genes. If you really look at it, most disorders are related in some way.


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