Thursday 28 Jan 2016 - 13:18 Makkah mean time-18-4-1437
Washington, (IINA) - A game-changing study described as a 'turning point' in tackling mental illness has revealed the biological cause of schizophrenia, Mail Online health news reported.
For the first time, scientists have linked the devastating disease to a physical process, the 'pruning' of unwanted connections between brain neurons.
They hope the discovery will lead to more effective treatments targeting the disorder's roots rather than its symptoms.
During the teenage years, the brain undergoes widespread re-wiring that involves 'synaptic pruning'.
The new study, based on a genetic analysis of nearly 65,000 people from around the world, pinpointed a defective gene that appears to trigger excessive pruning.
Scientists believe it is this that underlies the symptoms of schizophrenia, a severe psychotic condition marked by a loosening grip on reality, delusions, paranoia and hallucinations.
They hope the discovery will lead to more effective treatments targeting the disorder's roots rather than its symptoms.
During adolescence, the brain undergoes widespread re-wiring that involves 'synaptic pruning'.
Schizophrenia affects more than 21 million people worldwide and typically begins in late adolescence or early adulthood. Half of people living with schizophrenia do not receive care for the condition, according to the World Health Organization, WHO.
However, even when they do, existing drugs don't get to the root of the illness and there have been few advances in the last 50 years. Lead researcher Dr Steven McCarroll, from Harvard Medical School in, said: 'Since schizophrenia was first described over a century ago, its underlying biology has been a black box, in part because it has been virtually impossible to model the disorder in cells or animals.
'The human genome is providing a powerful new way in to this disease. Understanding these genetic effects on risk is a way of prying open that black box, peering inside, and starting to see actual biological mechanisms.'
The gene, complement component 4 (C4), plays an important role in the immune system, marking infectious microbes out for destruction. Because of this, initial genetic analysis suggested the possibility that an infectious agent might trigger schizophrenia.
A strong signal associated with the disease appeared in a region of DNA well known to be linked with infectious disease. C4 was found to have another role in the maturing brain, marking out or 'tagging' connections for pruning. The findings, reported in the journal Nature, could explain why schizophrenia usually strikes during late adolescence.
Brains of people with the disease also tend to have a thinner cerebral cortex, the outer layer of neural tissue that processes sensory information and plays a key role in thinking and consciousness, with fewer synapses, or connections. Bruce Cuthbert, of the National Institute of Mental Health in the U.S., said: 'This study marks a crucial turning point in the fight against mental illness.
'Because the molecular origins of psychiatric diseases are little-understood, efforts by pharmaceutical companies to pursue new therapeutics are few and far between. 'This study changes the game. Thanks to this genetic breakthrough we can finally see the potential for clinical tests, early detection, new treatments, and even prevention.'
The latest research suggests that a rogue version of the gene strips away too much material, triggering the symptoms of schizophrenia.
Therefore, drugs that 'turn down' the amount of tidying could prove to be valuable new treatments, the study reports. Eric Lander, director of the Broad Institute in the U.S., one of several universities behind the discovery, said: 'For the first time, the origin of schizophrenia is no longer a complete black box.
'While it's still early days, we've seen the power of understanding the biological mechanism of disease in other settings.
'Early discoveries about the biological mechanisms of cancer have led to many new treatments and hundreds of additional drug candidates in development.
'Understanding schizophrenia will similarly accelerate progress against this devastating disease that strikes young people.'
British expert Professor Mike Owen, director of the Medical Research Council Centre for Neuropsychiatric Genetics & Genomics at Cardiff University, said: 'The possibility that excessive synaptic pruning plays a role in schizophrenia has always been intriguing but largely unsupported by convincing evidence.
'But these findings change that, and might also help explain why the symptoms of schizophrenia tend to become manifest in adolescence and early adulthood when synaptic pruning is taking place.
'New research will be needed to understand exactly how C4 plays a role in synaptic pruning and schizophrenia and how this process interacts with other genes and proteins that have been implicated in the disorder.
'Treatment implications are unclear at the present time but this new work points the finger at a particular process and implicates a set of potential new targets which will need to be explored in experimental systems.'
SM/IINA
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