WEDNESDAY, May 16 (HealthDay News) -- One in three children with an older sibling who has an autism spectrum disorder, or problems with social interaction and communication, shows signs of developmental delay or autism-related behaviors by the age of 3 years, according to a new study.
"It is clear that the younger siblings of a child with an ASD [autism spectrum disorder] may face challenges even if they are not themselves identified with an ASD," study author Daniel Messinger, a professor at University of Miami College of Arts and Sciences, said in a university news release.
"This new work identifies classes of outcomes in these children. We found that the majority of these high-risk siblings appear to be developing normally. However, a higher-than-expected proportion of the children face challenges related to higher levels of autism-related behaviors or lower levels of verbal and nonverbal developmental functioning," Messinger added.
Messinger is scheduled to present the study findings at the International Meeting for Autism Research, May 18 in Toronto.
Autism spectrum disorders are neurodevelopmental conditions thought to affect 1 in 88 U.S. children. Autism is the most severe form. A milder form along the spectrum is Asperger syndrome.
The younger siblings of kids with autism spectrum disorders show lower levels of both verbal and nonverbal communication, as well as higher levels of autism-related behaviors, such as less interactive play with others and less expression of interest in what is going on around them.
Although most high-risk siblings are developing normally by 3 years of age, a substantial minority of children has more subtle autism-related problems or developmental delays, the researchers noted.
The data and conclusions of research presented at medical meetings should be viewed as preliminary until published in a peer-reviewed journal.
The U.S. National Institute of Neurological Disorders and Stroke has more about autism.
-- Mary Elizabeth Dallas
SOURCE: University of Miami, news release, May 16, 2012
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