Younger siblings of children with autism spectrum disorder (ASD) are at high risk for developing ASD as well as features of the broader autism phenotype. About 20% of younger siblings of children with Autism Spectrum Disorder (ASD) will develop the condition by age 3. A study by Yale School of Medicine researchers has found that 57% of these younger siblings who later develop the condition already showed warning signs like poor eye contact and repetitive behaviors at just a year and a half old. Published in the Journal of the American Academy of Child & Adolescent Psychiatry, this is the first large-scale, multi-site study aimed at identifying specific social-communicative behaviors that distinguish infants with ASD from their typically and atypically developing high-risk peers as early as 18 months of age. For the study, researchers looked at data on 719 infants who had older siblings on the spectrum. The children were assessed at 18 months and again at 36 months to identify social, communication and repetitive behaviors that could be predictive of autism.
Three distinct combinations of features at 18 months were predictive of ASD outcome: 1) poor eye contact combined with lack of communicative gestures and giving; 2) poor eye contact combined with a lack of imaginative play; and 3) lack of giving and presence of repetitive behaviors, but with intact eye contact. These 18-month behavioral profiles predicted ASD versus non-ASD status at 36 months with 82.7% accuracy in an initial test sample and 77.3% accuracy in a validation sample. Clinical features at age 3 among children with ASD varied as a function of their 18-month symptom profiles. Children with ASD who were misclassified at 18 months were higher functioning, and their autism symptoms increased between 18 and 36 months.
"While the majority of siblings of children with ASD will not develop the condition themselves, for those who do, one of the key priorities is finding more effective ways of identifying and treating them as early as possible," said lead author Katarzyna Chawarska, associate professor in the Yale Child Study Center and the Department of Pediatrics at Yale School of Medicine. "Our study reinforces the need for repeated diagnostic screening in the first three years of life to identify individual cases of ASD as soon as behavioral symptoms are apparent." Early detection, especially when toddlers have siblings with autism, is critical. Chawarska added, "Linking these developmental dynamics with underlying neurobiology may advance our understanding of causes of ASD and further efforts to personalize treatment for ASD by tailoring it to specific clinical profiles and their developmental dynamics."
Other authors of the study included: Suzanne Macari, Frederick Shic, Daniel J. Campbell, Jessica Brian, Rebecca Landa, Ted Hutman, Charles A. Nelson, Sally Ozonoff, Helen Tager-Flusberg, Gregory S. Young, Lonnie Zwaigenbaum, Ira L. Cohen, Tony Charman, Daniel S. Messinger, Ami Klin, Scott Johnson, and Susan Bryson.
“18-Month Predictors of Later Outcomes in Younger Siblings of Children With Autism Spectrum Disorder: A Baby Siblings Research Consortium Study.” Published online
of the American Academy of Child & Adolescent Psychiatry.
Citation: JACC doi: 10.1016/j.jaac.2014.09.015
Source: Yale University
Lee A. Wilkinson, PhD, CCBT, NCSP is author of the award-winning book, A Best Practice Guide to Assessment and Intervention for Autism and Asperger Syndrome in Schools, published by Jessica Kingsley Publishers. He is also editor of a text in the APA School Psychology Book Series, Autism Spectrum Disorder in Children and Adolescents: Evidence-Based Assessment and Intervention in Schools and author of the new book, Overcoming Anxiety and Depression on the Autism Spectrum: A Self-Help Guide Using CBT.