Essentially, at the neural stem cell stage when the cells were about to become nerve cells, a certain group of genes – some of which have previously been linked to autism – switched on earlier, leading to accelerated development. The nerve cells of people with ASD grew faster and ultimately larger than the neurons of people without ASD, as they developed longer, more complex branches than non-ASD cells. The findings are published in the journal Nature Neuroscience.
“Although our work only examined cells in cultures, it may help us understand how early changes in gene expression could lead to altered brain development in individuals with ASD,” said senior author Rusty Gage. As well as the fact that the study was conducted using cell cultures outside the body, it’s important to note that the number of participants from which the cells were taken is small.
One issue with understanding ASD and its causes is that, as its name suggests, ASD is very much a spectrum. The term encompasses a range of disorders, such as autism and Asperger's syndrome. The severity of ASD can vary widely, and those with the condition can be affected in different ways. The new study used cells from people with a specific kind of autism that causes an enlarged brain, so the findings might not apply to everyone with ASD.
“We hope these studies will serve as a framework for developing novel approaches for diagnosis during an early period of child development – long before behavioral symptoms manifest – to have the maximum impact on treatment and intervention,” said Schafer.
“This research could provide a basis for discovering the common pathological traits that emerge during ASD development.”