Researchers at the Yale School of Medicine’s Child Study Center have discovered at least two different types of autism. The findings, publishedin the journal Nature Neuroscience, suggest a need for more than just one drug to treat symptoms.
In one set of patients, researchers found that children who had both autism and macrocephaly — a larger than normal-sized head — had an excess growth of excitatory neurons. These are neurons that excite and activate nearby brain cells. But another group of children with autism, and without macrocephaly, had a deficit of those same neurons.
“This is important because if we're thinking about treatments, it may not be applicable in the same way to everybody with the same symptoms,” said Dr. Flora Vaccarino, the Harris Professor in the Child Study Center and co-senior author of the paper. “And we need to understand more about this variety in order to better treat patients that are in front of us.”
Researchers took skin cells from patients with autism and from their fathers who did not have autism. They then grew organoids to model brain development in vitro. The study was co-led by Alexandre Jourdon, Feinan Wu and Jessica Mariani, all from Vaccarino’s lab.
“The findings are of interest and certainly warrant further investigation from a wider, more diverse sample,” said Jennifer Twachtman-Bassett, autism specialist at Connecticut Children’s, who wasn't involved with the Yale research. “It is worth noting the sample size appears to be very small at just 13 participants.”
Twachtman-Bassett said that in order for this information to be used for diagnosis, a large amount of group data would need to be translated into normal and abnormal trajectories or ranges that could be detected via a test.
“Despite the recent explosion in our knowledge of brain development and early child development, our ability to explain how specific deviations in brain development may contribute to disorders is still relatively limited,” said Dr. Paul Dworkin, a developmental-behavioral pediatrician, also at Connecticut Children’s.
A better understanding of the biological basis for such complex disorders as autism may enable physicians to target treatments to achieve the best possible outcomes, he said.
About 20% of all autism cases are among people with macrocephaly, and researchers said these cases tend to be more severe.
