'An important piece of the puzzle': Scientists discover why gene mutation leads to autism

Jorge L. Ortiz | USA TODAY

Show Caption Hide Caption Auditorium goes silent so student with autism can accept diploma Students at a high school graduation in New York stayed silent so a student with autism would feel comfortable while accepting his diploma on stage.

The search for the reasons behind intellectual disabilities and autism in children has just advanced by a significant step.

Scientists at Northwestern University outside Chicago have discovered why these conditions develop in the nascent brain, raising hopes that better treatment for them can be found.

The researchers determined mutations in a gene called Usp9x lead to the brain growing fewer synapses, the junctions between neurons that transmit and receive electrical signals. That results in decreased communication between the brain cells, which is critical for learning.

Children with the mutation not only show developmental delays and difficulty learning, but also heightened anxiety and hyperactivity.

“We have solved an important piece of the puzzle in understanding how this mutation causes intellectual disabilities and mental illness,” said Peter Penzes, director of the Center for Autism and Neurodevelopment at Northwestern’s medical school and lead author of a paper on the subject that will be published Thursday in the journal Neuron.

According to the Centers for Disease Control and Prevention, 1 in 59 children in the U.S. is diagnosed with autism spectrum disorder (ASD), a developmental disability that affects communication, behavior and interaction with other people. Boys are four times more likely to be diagnosed than girls, and the symptoms usually appear in the first few years of a child’s life.

The advocacy organization Autism Speaks says 31% of children on the spectrum have an intellectual disability. The CDC points out that, while there’s currently no cure ASD, early diagnosis and intervention can enhance development.

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Penzes said the new findings could have several implications regarding treatment.

“Autism and intellectual disability (ID) are very heterogenous diseases,’’ Penzes said via email. “If we try to treat them only based on symptoms, it may be very challenging. But if we understand the genetic cause of each patient’s type of autism, we can use this knowledge to classify and treat subtypes of autism and ID based on what molecular pathways are altered.’’

In addition, Usp9x has been linked to cancer, which has drawn the interest of drug makers. That might provide a leg up on finding new ways to treat neurodevelopmental disorders that include not only ASD and intellectual disability but also schizophrenia and bipolar disorder.

“We will start by searching byproducts of recent cancer drug screens,’’ Penzes said. “This could be a shortcut to finding a drug for some patients.’’