OBJECTIVE: Difficulties in social communication is core syptoms of autism spectrum disorder (ASD), and it is often present in first-degree relatives in varying degrees. However, these subclinical autistic traits, which are thought to be related to genetic susceptibility factors, may be heterogeneous in family members. This prospective, the aim of this study was to compare unaffected siblings of children with ASD in terms of theory of mind, empathy skills, and broad autism phenotype (BAP).
METHODS: Fourty-one children who were diagnosed Autistic Disorder, Asperger Disorder and Pervasive Developmental Disorder-not otherwise specified according to Diagnostic and Statistical Manual of Mental Disorders, 4th Edition and their unaffected siblings and 43 controls of typically developing children were included. The Schedule for Affective Disorders and Schizophrenia for School-age Children – Present and Lifetime Version was conducted all children with the aim of excluding a psychiatric diagnosis. False-belief tasks and Emotion Recognition Scales were used to evaluate theory of mind and empathy skills. The Social Communication Questionnaire was administered by the clinician in order to evaluate subthreshold autistic symptoms.
RESULTS: Unaffected siblings of ASD children exhibited worse performance in theory of mind and emotion recognition tasks. Additionally, these children had more autistic symptoms and there was a correlation with autism symptoms and social cognition tasks.
DISCUSSION: In compatible with BAP, the results indicated that the siblings of children with ASD showed a neurocognitive profile associated with ASD at a slight level, and they had more subsyndromal autism symptoms compared with healthy children. The findings also indicated that there was a weakness in skills of empathy and theory of mind ability of siblings of ASD.