Study finds that a subset of children often considered to have autism may be misdiagnosed

Children with a genetic disorder called 22q11.2 deletion syndrome, who frequently are believed to also have autism, often may be misidentified because the social impairments associated with their developmental delay may mimic the features of autism, a study by researchers with the UC Davis MIND Institute suggests.

The study is the first to examine autism in children with chromosome 22q11.2 deletion syndrome, in whom the prevalence of autism has been reported at between 20 and 50 percent, using rigorous gold-standard diagnostic criteria. The research found that none of the children with 22q11.2 deletion syndrome "met strict diagnostic criteria" for autism.

The researchers said the finding is important because treatments designed for children with autism, such as widely used discrete-trial training methods, may exacerbate the anxiety that is commonplace among the population.

Rather, evaluations should be performed to assess autism and guide the selection of appropriate therapies based on the children's symptoms, such as language and communication delay, the researchers said. The study, "Social impairments in Chromosome 22q11.2 Deletion Syndrome (22q11.2DS): Autism Spectrum Disorder or a different Endophenotype?" is published online today in Springer's Journal of Autism and Developmental Disorders.

A high prevalence of autism spectrum disorder has been reported in children with 22q11.2 deletion syndrome – as high as 50 percent based on parent-report measures. Children diagnosed with 22q11.2 deletion syndrome – or 22q – may experience mild to severe cardiac anomalies, weakened immune systems and malformations of the head and neck and the roof of the mouth, or palate. They also experience developmental delay, with IQs in the borderline-to-low-average range. They characteristically experience significant anxiety and appear socially awkward.

"The results of our study show that of the children involved in our study no child actually met strict diagnostic criteria for an autism spectrum disorder," said Kathleen Angkustsiri, study lead author and assistant professor of developmental-behavioral pediatrics at the MIND Institute.

"This is very important because the literature cites rates of anywhere from 20 to 50 percent of children with the disorder also have an autism spectrum disorder. Our findings lead us to question whether this is the correct label for these children who clearly have social impairments. We need to find out what interventions are most appropriate for their difficulties."

The disorder's name also describes its location on the 22nd chromosome as well as the nature of the genetic mutation, which is associated with a variety of anatomical and intellectual deficits. It has previously been known as Velocardiofacial Syndrome and Di George Syndrome, for the pediatric endocrinologist who described it in the 1960s.

The risk of 22q is about 1 in 2000 in the general population. The condition is seen in individuals of all backgrounds. Notably, people with 22q are at significantly heightened risk of developing mental-health disorders in adolescence and young adulthood. A person with 22q has a 30 times greater risk of developing schizophrenia than individuals in the general population.