In utero brain proliferation is linked to the severity of autism spectrum disorders, according to a recent study.
- Cerebral cortical organoids are responsible for consciousness, thinking, reasoning, learning, memory, emotion, and sensory functions.
- In autistic children, they increased about four times faster than in neurotypical toddlers.
- The larger the size of the cerebral cortical organoids at the embryonic stage, the more severe the social and language manifestations were.
A deficit in communication and social interaction as well as a restriction and repetition of behaviors, interests and activities are at the heart of autism spectrum disorders (ASD) but their severity varies from one child to another. Indeed, some autistic children see their abilities improve from a very young age and develop good social and language skills, while others, with “profound” autism, have social, language and cognitive skills that remain weak and require care throughout their life. “The biological origins of these opposing subtypes of ASD social severity and developmental trajectories are not known,” said researchers from the University of California in San Diego (USA). That is why they decided to carry out a study published in the journal Molecular Autism.
ASD “involves early brain overgrowth and excess neurons”
As part of the work, the scientists measured the size and growth of 4,910 embryonic cerebral cortical organoids, “since autism spectrum disorders involve early brain overgrowth and an excess of neurons.” The cerebral cortical organoids, which are responsible for consciousness, thought, reasoning, learning, memory, emotion and sensory functions, were taken from 10 children, aged one to four, affected by idiopathic autism (in which no monogenic cause has been identified). Then, six other healthy toddlers were recruited for comparison.
Brain cortical organoids of autistic children developed at an accelerated rate
According to the results, the cerebral cortical organoids of the young autistic volunteers were significantly larger by about 40% than those of the control patients. The larger the size of the cerebral cortical organoids at the embryonic stage, the more severe the social manifestations of autism spectrum disorders, the more reduced social attention, language skills and IQ were, and the more “atypical” the growth of brain regions related to social life and language. The authors also found that rapid growth of cerebral cortical organoids in toddlers affected by autism was correlated with the onset of the disorder. “At the cellular level, children with profound autism showed accelerated neurogenesis (the formation of neurons from stem cells). This is not always for the best!” concluded the researchers.