Scientists claim they have found the root cause of autism. They assert that person/s with the condition carry countless synapses in their brains —– spots where neurons join and communicate, a new study has discovered. Scientists at Columbia University in New York feel that the excess synapses are generated due to lack of ‘pruning’ that usually come about early in life. The finding is a big breakthrough to discerning the complicated condition and builds hope of possible treatment, researchers said.
In mice carrying autistic traits, scientists were able to bring back the synaptic pruning and lessen symptoms. Employing a drug commonly used to subdue the immune systems of transplant patients, they discovered the autistic-like behaviours were mitigated. The drug, rapamycin, cause side effects imply, is not fit to treat autism. The discovery opens doors to possibilities of varied therapies which can cut the number of synapses, assert the study published in the journal Neuron. Professor Jeffrey Lieberman, chair of psychiatry at Columbia University Medical Center in New York, where the research took place, said: ‘This is an important finding that could lead to a novel and much-needed therapeutic strategy for autism.’
Autism, trouble near about 500,000 people in the UK, and covers an array of behavioural disorders that lessen the power of affected to interact with and relate to other people. Scientists believe that it is prompted by a mash-up of genetic and environmental factors that impact on the developing brain. As the brain develops an outbreak of synapse formation occurs in infancy, mostly in the cortex – a region closely connected to autistic behaviour. Pruning discards nearly half of these cortical synapses by late adolescence. Synapses are believed to be affected by diverse genes related to autism, triggering speculation about the role they play in the condition.
Scientists at Columbia University studied the brains of 26 autistic children and young people in the age-range of two to 20 who had died due to different causes. By late childhood, the researchers discovered that spine density had fallen by nearly 50% in the healthy brains, but by only 16% in the brains of autistic individuals. Lead researcher Professor David Sulzer opined: ‘It’s the first instance that anyone has examined, and seen, a lack of pruning in the course of development of children with autism, although lesser numbers of synapses in certain brain areas have been observed in brains from older patients and in mice with autistic-like behaviours.’
In laboratory mice, the pruning issue was tracked to a protein termed mTOR which when over-active subdued the power of brain cells to prune themselves. Big quantities of the over-active protein were also existent in the brains of autism affected, the scientists discovered. Rapamycin suppressed mTOR and brought back normal autophagy and synaptic pruning in the mice, even at a stage when the animals started to show-up signs of autism.
Professor Sulzer stated: ‘Now that we can see the alterations in behaviour – it’s an indication that autism in fact can be treated after a child is diagnosed, if we can invent an effective drug. He added: ‘People usually link learning to need of formation of new synapses, however, removal of unfit synapses may be just as important. ‘One great thing about the discovery is that tons of genes have been associated to autism, but a majority of our human subjects had overactive mTOR and decreased autophagy,, and most seem to have a lack of normal synaptic pruning.’