Girls are diagnosed with autism spectrum disorder (ASD) later than boys because females exhibit less severe symptoms, says a study.
Females also have different symptoms than males, possibly contributing to later identification of the disease, it added.
"This suggests that girls with ASD, as well as perhaps older women with this disorder, differ from males in key symptoms and behaviours, particularly around social interactions," said Paul Lipkin, director of the interactive autism network at Kennedy Krieger Institute in Maryland.
For the study, the researchers analysed data from an online registry that includes almost 50,000 individuals and family members affected by ASD. In the data review, researchers found that girls were diagnosed with pervasive developmental disorder, an ASD impacting the development of many basic skills, at a mean age of four years compared to 3.8 years for boys.
In addition, they found girls struggled more with social cognition -- the ability to interpret social cues. Meanwhile, boys had more severe mannerisms such as repetitive behaviours like hand flapping, as well as highly restricted interests.
Older boys, ages 10-15, also had more difficulties with the ability to recognise social cues and use language in social situations.
The findings were presented at the Paediatric Academic Societies (PAS) annual meeting in San Diego on Tuesday.
