Difficulties in diagnosing autism may be due to dynamic changes during child development Researchers from the Center for Autism Research (CAR) at Children's Hospital of Philadelphia (CHOP) found that difficulties in diagnosing toddlers with autism spectrum disorder (ASD) might be due to the dynamic nature of the disorder during child development. Children with clinical characteristics that put them on the diagnostic border of autism have an increased susceptibility to gaining or losing that diagnosis at later ages. The findings were published online by The Journal of Child Psychology and Psychiatry. While most children diagnosed with ASD at early ages retain their diagnosis, a significant number of children have more dynamic presentations of clinical features associated with autism and may show changes as they develop, particularly around the time they are between two and three years old.