The motion of head turning is hypersensitive to children who carry a variant of a gene associated with severe autism.
Scientists in California have linked the disruption of a sensitive eye reflex to profound autism, according to researchers.
This, they said, offers opportunities for faster diagnosis and new treatment of the disease, which is a developmental disability caused by differences in the problem. People with autism spectrum disorder, which is usually diagnosed at the age of two, often encounter difficulties with social interaction and communication, as well as restricted or repetitive behaviors or interests. Learning, moving, or paying attention may be different for them.
Since the United Nations General Assembly designated April 2 as World Autism Awareness Day in 2007, member nations have marked the day as a means to affirm and promote the full realization of all human rights and fundamental freedoms for autistic people on an equal basis with others.
The researchers at the University of California at San Francisco believe they’ve uncovered a fresh method to screen for autism by observing how children’s eyes move when they look up.
The researchers found that children who carry a variant of a gene associated with severe autism are hypersensitive to this motion. A method that only requires them to wear a helmet and sit in a chair could help diagnose kids earlier and faster.
The clinic and lab could benefit from this, they enthused.
The study’s senior author, Kevin Bender, said it’s possible to measure it in kids with autism who can’t talk or don’t want to follow instructions. Impaired cerebral plasticity hypersensitizes sensory reflexes in SCN2A-associated ASD, according to research published in Neuron.
Research into autism is being advanced.
An ion channel that coordinates movement is made by the gene SCN2A. How cells function is dependent on ion channels, which allow electrical charges in and out of cells. A number of variants of this gene are also associated with severe epilepsy and intellectual impairment. Among the hundreds of gene mutations associated with autism, variants of the SCN2A gene are among the most common.
The researchers found that children with these variants have an unusual form of the reflex that stabilizes the gaze while the head is moving, called the vestibulo-ocular reflex (VOR) A simple eye-tracking device can be used to measure how much it goes overboard in children with autism.
One out of every 36 children in the US is affected by autism, according to the discovery. The number of children and adolescents with a formal diagnosis of autism spectrum disorder (ASD) aged one year to 17 who were eligible for services increased from 14,914 in 2017 to 32,222 in 2021, according to data from Israel’s National Insurance Institute. Adults with ASD aren’t included.
The two-fold increase in ASD prevalence from 0.49% to 0.96% over the five-year period is represented by the increase. Greater awareness of the disorder and parents bringing their toddlers for testing are what this means.
The frontal lobe of the brain that controls language and social abilities in people was the focus of ion-channel experts like Bender. However, mice with an autism-associated variant of the SCN2A gene did not demonstrate marked behavioral differences associated with this brain region.
The first author of the study, Chenyu Wang, a graduate student in Bender’s lab, looked into what the SCN2A variant was doing in the mouse cerebellum. The equipment needed to test behaviors influenced by the cerebellum, such as the VOR, was already in the possession of Guy Bouvier, a cerebellum specialist at the university and co-senior author of the paper.
It is easy to trigger this reflex. Your eyes will stay roughly centered if you shake your head and shake your head. The researchers found that this reflex was particularly sensitive in mice with the SCN2A variant. The mice’s eyes compensated for the rotation in one direction by rotating in the opposite direction.
There was a cost to this increased sensitivity. The cerebellum’s neural networks can adjust the reflex when necessary, for instance, to allow the eyes to focus on a moving object while the head’s also moving. In SCN2A mice, however, these circuits became stuck, making the reflex rigid.
The behavior Wang and Bender observed was unique, resulting from a variant of the SCN2A gene that was easy to measure in mice. Would it work in people, though? A helmet-mounted eye-tracking camera was the way they decided to test it. Being that the two scientists had never conducted such a study on humans before, Wang called it a “shot in the dark.”
Several families from the FamilieSCN2A Foundation, the leading US family advocacy group for children with SCN2A variants, were asked to participate.Bender asked several families from the FamilieSCN2A Foundation to participate. There were five children with SCN2A autism and 11 siblings who weren’t affected.
The kids were rotated to the left and right in the office chair to the beat of the clock. In the children with autism, the VOR was hypersensitive, but not in their neurotypical siblings. Measuring how much their eyes moved in response to their head rotation revealed which kids had autism.
A CRISPR-based technology that restored SCN2A gene expression in the cerebellum was used by the researchers to restore the normal eye reflex in mice. The 30-day-old SCN2A mice, which is the equivalent of late adolescence in humans, were treated, and their VOR became less rigid, but they were still incredibly sensitive to body movement. Their eye reflexes were completely normal when they treated 3-day-old SCN2A mice, early childhood in humans.
The first results, using this reflex as a proxy for autism, point to an early window for future treatments that get the developing brain back on track, Wang said. It’s too early to say if such a strategy could one day be employed to directly treat autistic individuals. The eye reflex test, taken on its own, could pave the way for a quicker autism diagnosis for kids today, avoiding a lengthy diagnostic journey.
Bender concluded, “If this sort of assessment works in our hands, with kids with profound, nonverbal autism, there is hope it could be more widely adopted.”
The research was reported by the jpost