On February 3, researchers published a study in Nature Neuroscience identifying a connection between Autism Spectrum Disorder (ASD) and an abnormality in the cells that produce myelin. “If we get to these kids really early, we might be able to change their developmental trajectory and improve their outcomes,” Brady Maher, a lead investigator at the Lieber Institute for Brain Development and an associate professor in the psychiatry department at Johns Hopkins School of Medicine told NPR of the study’s findings.
After studying the brains of both mice and humans affected by autism, researchers noticed an abnormality in the cells that produce myelin, called oligodendrocytes. Essentially, myelin “insulates” the brain circuits, allowing traffic signals to move smoothly through them like an information highway. Having too much or too little myelin can result in a range of neurological problems by essentially disrupting the traffic flow of signals moving through the brain.
Multiple Sclerosis (MS), for example, causes your immune system to attack the central nervous system, damaging the myelin sheath that protects your nerves and preventing them from sending and receiving messages to and from your brain. It’s as though someone has stripped off the coating that protects livewires, leaving them exposed and vulnerable to damage. MS can affect a number of physical and mental issues, from muscle control to learning and thinking.
The study may be the linchpin in explaining why ASDs are so varied and complex. Maher claims that “myelination could be a problem that ties all of these autism spectrum disorders together.” Maher said, if caught early enough, it’s possible to prevent or reverse symptoms by administering drugs that positively affect myelination.
Dr. Flora Vaccarino, a professor in the neuroscience department at Yale who was not involved in the research, told NPR the study adds to mounting evidence that myelination problems are present in “several developmental disorders and in particular in autism.” She claims it also shows how “one faulty regulatory system in the brain can lead to either too much myelination or too little.” This may explain why people with ASD may have brains that are larger or smaller than average.
As with most medical discoveries, the myelination problem arose as researchers were trying to solve something else. They were studying brain cells in mice with a gene mutation that causes Pitt-Hopkins syndrome, which can include features of autism spectrum disorder. “We saw a signature that suggested there might be something wrong with myelination,” Maher said, which came as a surprise to the team.
As the team experimented further, they were able to confirm a clear connection between a deficit in oligodendrocytes and mice not only with Pitt-Hopkins syndrome, but with other models of autism as well. Next, a biostatistics expert named Andrew Jaffe analyzed the brain tissue from people with autism who had died. His genetic analysis uncovered problems with myelination.
Dr. Daniel Weinberger, director of the Lieber Institute and a professor at Johns Hopkins, told NPR that in order to reverse, mitigate or manage brain myelination, treatment would have to begin as early as possible.
“(Brain myelination) really does not start in earnest until the first year or two of life,” Weinberger said. “And this is around the time that autism is first apparent.“
Autism Myelin — Sources:
NPR.org
Nature Neuroscience
Dr. Daniel Weinberger
Dr. Andrew Jaffe
Dr. Flora Vaccarino
Brady Maher