A Prospective Study of Autistic-Like Traits in Unaffected Siblings of Probands With Autism Spectrum Disorder
CONTEXT The presence of autistic-like traits in relatives of individuals with autism spectrum disorder (ASD) is well recognized, but, to our knowledge, the emergence of these traits early in development has not been studied. OBJECTIVE To prospectively investigate the emergence of autistic-like traits in unaffected (no ASD diagnosis) infant siblings of probands diagnosed as having ASD. DESIGN Two groups of children unaffected with ASD were assessed prospectively-siblings of probands diagnosed as having ASD (high risk [HR]) and control subjects with no family history of ASD (low risk [LR]). Scores on a measure of autistic-like traits at 12 months of age were used in a cluster analysis of the entire sample. SETTING A prospective study of infant siblings of probands with ASD from 3 diagnostic centers in Canada. PARTICIPANTS The study included 170 HR and 90 LR children, none of whom was diagnosed as having ASD at age 3 years. MAIN OUTCOME MEASURES The Autism Observation Scale for Infants was used to measure autistic-like traits and derive clusters at 12 months of age. Clusters were compared on ASD symptoms, cognitive abilities, and social-emotional difficulties at age 3 years. RESULTS Two clusters were identified. Cluster 1 (n = 37; 14.2% of total sample) had significantly higher levels of autistic-like traits compared with cluster 2. Within cluster 1, 33 children came from the siblings (19.4% of HR group) and only 4 came from the control subjects (4.5% of LR group). At age 3 years, children from cluster 1 had more social-communication impairment (effect size > 0.70; P < .001), lower cognitive abilities (effect size = -0.59; P < .005), and more internalizing problems (effect size = 0.55; P = .01). Compared with control subjects, HR siblings had a relative risk of 4.3 (95% CI,1.6-11.9) for membership in cluster 1. CONCLUSIONS Study findings suggest the emergence of autistic-like traits resembling a broader autism phenotype by 12 months of age in approximately 19% of HR siblings who did not meet ASD diagnostic criteria at age 3 years.
Available from: Ewa Pisula
- "In addition, no differences were found between 7-and 13-month-old children from these groups in terms of performance in tasks related to gaze following (Bedford et al., 2012). A study by Georgiades et al. (2013) revealed no deficits in the area of pragmatic language among 12-month-old infants. "
Available from: Devon N Gangi
- "The BAP refers to subclinical differences in traits and abilities seen in family members of individuals with ASD (Gerdts & Bernier, 2011). Patterns similar to those observed in this study have been reported at 12 months among high-risk siblings without an eventual ASD diagnosis who were over-represented in clusters of infants exhibiting difficulties on the Autism Observation Scale for Infants (AOSI), which includes measures of affective response, coordination of gaze and action, and social-communicative behaviors (Georgiades et al., 2013). Differences in anticipatory smiling and related behaviors between high-risk siblings (including those without ASD) and low-risk siblings suggests the possibility that difficulties communicating preexisting positive affect to a social partner may characterize the early BAP. "
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ABSTRACT: Infants at risk for autism spectrum disorders (ASD) may have difficulty integrating smiles into initiating joint attention (IJA) bids. A specific IJA pattern, anticipatory smiling, may communicate preexisting positive affect when an infant smiles at an object and then turns the smile toward the social partner. We compared the development of anticipatory smiling at 8, 10, and 12 months in infant siblings of children with ASD (high-risk siblings) and without ASD (low-risk siblings). High-risk siblings produced less anticipatory smiling than low-risk siblings, suggesting early differences in communicating preexisting positive affect. While early anticipatory smiling distinguished the risk groups, IJA not accompanied by smiling best predicted later severity of ASD-related behavioral characteristics among high-risk siblings. High-risk infants appear to show lower levels of motivation to share positive affect with others. However, facility with initiating joint attention in the absence of a clear index of positive affective motivation appears to be central to the prediction of ASD symptoms.
Available from: Jillian Filliter
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