As many as one in four children with autism go undiagnosed -- and, the majority of those in whom the disorder is missed are black or Hispanic.
Among the key findings in a study published Thursday in the journal Autism Research, researchers report that, despite increasing awareness of autism, many clinicians still fail to recognize it in young children under eight years of age, said study co-author Walter Zahorodny, an associate professor at Rutgers New Jersey Medical School and director of the New Jersey Autism Study, which contributed to the research.
"There may be various reasons for the disparity, from communication or cultural barriers between minority parents and physicians to anxiety about the complicated diagnostic process and fear of stigma," study co-author Walter Zahorodny, an associate professor at Rutgers New Jersey Medical School and director of the New Jersey Autism Study, said in a press release. "Also, many parents whose children are diagnosed later often attribute their first concerns to a behavioral or medical issue rather than a developmental problem."
According to the U.S. Centers for Disease Control and Prevention, approximately one in every 59 children is diagnosed with autism nationwide. Although symptoms vary, the disorder causes difficulties in social interactions with others and often results in repetitive behaviors, speech issues, memory problems and difficulties in understanding non-verbal cues.
Zahorodny and his team analyzed the education and medical records of 266,000 children who were eight years old in 2014, seeking to determine how many of them were not diagnosed with or received treatment for autism, despite showing symptoms of the disorder.
The research was conducted through the Autism and Developmental Disabilities Monitoring Network, a program funded by the U.S. Centers for Disease Control and Prevention that tracks the prevalence of the developmental disorder in 11 states: Arizona, Arkansas, Colorado, Georgia, Maryland, Minnesota, Missouri, New Jersey, North Carolina, Tennessee and Wisconsin.
Of the nearly 4,500 children identified, 25 percent were not diagnosed. Most were black or Hispanic males with deficits in mental abilities, social skills and activities of daily living who were not considered disabled.
According to Zahorodny, screening all toddlers, preschoolers and school-age children for autism could help reduce the disparities uncovered by he and his team. Clinicians can overcome communication barriers by using pictures or employing patient navigators to help families understand the diagnostic process, test results and treatment.
Finally, states can help improve access to care by requiring insurance companies to cover early intervention when a child is first determined to be at risk for autism rather than waiting for a diagnosis, he said.
Identifying children at risk for the disorder may be a bit easier in the future, based on the findings of another study published Thursday in the Journal of Neuroscience. As described in the article, researchers, using mice, discovered that brains lacking a key protein, p75NTR, may be predisposed to conditions like autism.
According to the authors, p75NTR, though not a gene specifically linked to autism, is part of a family of proteins needed for brain cells to develop, function and survive. Its absence causes an imbalance in brain circuitry that can lead to long-term cognitive and movement behaviors characteristic of autism spectrum disorder.
"During brain development, there is a coordinated series of events that have to occur at the right time and the right place in order to establish the appropriate number of cells with the right connections," Juan Pablo Zanin, Rutgers-Newark research associate, said in a statement. "Each of these steps is carefully regulated and if any of these steps are not regulated correctly, this can impact behavior."
Working with Wilma Friedman, professor of cellular neurobiology at Rutgers-Newark, Zanin has been studying p75NTR, which is vital in the regulation of cell division in the brain, to determine its exact function in brain development. The goal is to gain a better understanding of how this genetic mutation could cause brain cells to die off, potentially causing autism or neurological diseases like Alzheimer's.
Working in the laboratory with genetically engineered mice, the team found that those without the p75NTR protein had more brain cells than normal, causing problems in the cerebellum, the working unit of the brain that regulates movement and balance as well as cognitive function. The cerebellum is one of the key brain regions affected by autism.
They trained mice -- with and without the p75NTR protein -- to associate a quick puff of air with a blinking light. Mice with the protein learned to blink and shut their eyes when they saw the light while mice without the protein did not.
"It is important to understand how the brain's circuitry is built and how it regulates behavior normally," said Friedman. "This research shows us that when it is not generated properly it is going to have an impact on many behaviors."