Autism Is Not a Single Condition and Has No Single Cause, Scientists Conclude

"By linking genetic information to age at diagnosis, the researchers observed that the profiles of those identified early with the condition differed from those who received confirmation at later stages. They found only a slight overlap between the two groups, indicating that the biological mechanisms associated with autism in childhood may be different from those linked to autism identified in adolescence or adulthood."

"The analysis, published last week in the journal Nature, showed that children diagnosed before the age of six were more likely to have behavioral difficulties-such as problems with social interaction-from an early age. In contrast, those diagnosed after the age of 10 were more likely to experience social and behavioral difficulties during adolescence. They also had a greater predisposition to mental health conditions, such as depression."

"The study adds that the average genetic profile of those diagnosed later was closer to that of ADHD and conditions such as post-traumatic stress disorder than to that of "classic" autism identified in early childhood. The study concludes that the timing of diagnosis is not entirely random, but reflects underlying genetic differences that, in some cases, coincide with risk for other conditions."

Autism is not a single, homogeneous condition; early- and later-diagnosed cases often have distinct genetic and developmental profiles. Analysis of behavior during childhood and adolescence in the United Kingdom and Australia and genetic data from more than 45,000 patients in Europe and the United States linked genetic information to age at diagnosis. Profiles of those identified in early childhood differed markedly from those diagnosed in adolescence or adulthood, with only slight overlap. Children diagnosed before age six tended to show early social-interaction and behavioral difficulties, while those diagnosed after age ten developed social and behavioral problems in adolescence and showed greater predisposition to depression. Later-diagnosed profiles more closely resembled genetic patterns for ADHD and post-traumatic stress disorder than classic early-childhood autism, indicating diagnostic timing often reflects underlying genetic differences and comorbidity risk.

Read at WIRED