Characteristics of the broader phenotype in autism: A study of siblings using the Children's Communication Checklist-2

Department of Experimental Psychology, Oxford University, Oxford, United Kingdom.
American Journal of Medical Genetics Part B Neuropsychiatric Genetics (Impact Factor: 3.42). 03/2006; 141B(2):117-22. DOI: 10.1002/ajmg.b.30267
Source: PubMed


Non-autistic relatives of people with autistic disorder have an increased risk of social and communicative difficulties: this is known as the "broad phenotype." Better methods for characterizing the broad phenotype are needed to facilitate identification of risk genes for autism. 29 siblings of 20 children with autistic disorder, 13 siblings of 9 children with PDDNOS, and 46 typically developing control children from 26 families were assessed by parental report using the Children's Communication Checklist-2 (CCC-2). Groups were matched on age and IQ and siblings with autism were excluded. Group mean scores on the CCC-2 differed on only one subscale, syntax. However, siblings of children with autism or PDDNOS were over-represented in the tails of the distributions of several scales, and 10 (24%) scored more than 2 SD below the control mean on a total score based on all 10 subscales. Only two of these 10 children scored above threshold on one or more scales of the Autism Diagnostic Interview-Revised (ADI-R). Children with abnormal scores on the CCC-2 total were characterized by low-verbal IQ and their fathers tended to score high on the social and communication scales of the Autism Quotient, a measure of the broad phenotype in adults. The CCC-2 shows promise as a quick screening device for the broad phenotype in non-autistic siblings of children with autism.

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    • "Difficulties include, among others: pragmatic language deficits (e.g. [10] [12] [13] [32] [36] [44] [46] [55]), verbal fluency [22], reading abilities [25] [35], delay of language development and problems in language developmental history [11] [38] [43] [52], conversational skills [60] and syntax [41]. "

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    • "Rather than treating ASD as discrete entities with a categorical approach based on a distinct boundary between normality and pathology, several authors [4] [5] have suggested a dimensional approach to ASD, which conceptualises these disorders as the upper extreme of a constellation of deficits in social adaptation and communication that may be continuously distributed in the population . There are several lines of evidence for this notion: autistic traits measured in the general population show a smooth distribution throughout the normal range to the clinical extreme [6] [7]; relatives of patients with ASD display high levels of autistic traits [8] [9]; factor analytic approaches did not detect discontinuities between ASD and autistic traits [10]; known risk factors for ASD (e.g., paternal age at birth) have been shown to influence autistic traits [11]; common genetic variants that are, by their very nature, present in a significant proportion of the general population, are believed to play a role in the aetiology of ASD [12] [13] [14]. Indeed, the DSM-5 itself has highlighted the dimensional nature of the cardinal behavioural domains of ASD, by incorporating a severity scale to capture the 'spectrum' nature of ASD [1]. "
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    ABSTRACT: Background: In recent years, several twin studies adopted a dimensional approach to Autism Spectrum Disorders (ASD) and estimated the contribution of genetic and environmental influences to variation in autistic traits. However, no study was performed on adults over 18 years of age and all but two studies were based on parent or teacher ratings. Also, the genetic and environmental contributions to the interplay between autistic traits and adult personality dimensions have not been investigated. Methods: A sample of 266 complete twin pairs (30% males, mean age 40 ± 12 years) drawn from the population-based Italian Twin Register was administered the Autism-Spectrum Quotient, Temperament and Character Inventory (TCI-125), and General Health Questionnaire (GHQ-12). Genetic structural equation modelling was performed with the Mx program. Estimates were adjusted for gender, age, and GHQ-12 score. Results: Genetic factors accounted for 44% and 20%-49% of individual differences in autistic traits and TCI dimensions, respectively. Unshared environmental factors explained the remaining proportion of variance. Consistently with the notion of a personality profile in ASD characterised by obsessive temperament, autistic traits showed significant phenotypic correlations with several TCI dimensions (positive: HA; negative: NS, RD, SD, C). Genetic and unshared environmental correlations between AQ and these TCI dimensions were significant. The degree of genetic overlap was generally greater than the degree of environmental overlap. Conclusions: Despite some limitations, this study suggests that genetic factors contribute substantially to individual differences in autistic traits in adults, with unshared environmental influences also playing an important role. It also suggests that autistic traits and the majority of temperament and character dimensions share common genetic and environmental aetiological factors.
    Comprehensive Psychiatry 12/2014; 58. DOI:10.1016/j.comppsych.2014.12.018 · 2.25 Impact Factor
    • "However, given that SCD criteria require that a child demonstrate all four symptoms (i.e., difficulties in using communication for social purposes, changing communication to fit the context or needs of the listener, following rules of conversation and narrative, and using and understanding nonliteral language), including those that develop later in childhood, it is unlikely that any of our participants would have met criteria, even had they been available at the time of data collection. A crucial question is whether there is developmental continuity between the classifications of PLI by the LUI in this sample of 3-year-old children with a family history of ASD, and PLI classifications at later ages using instruments like the Children's Communication Checklist (Bishop, 2003), which focus on later-developing aspects of pragmatic language. Additionally, whether those children identified as pragmatically impaired in the present sample actually evidence clinically significant impairment, and/or would meet criteria for SCD at older ages, remain important questions. "
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    ABSTRACT: Background We evaluated early pragmatic language skills in preschool-age siblings of children with autism spectrum disorder (ASD), and examined correspondence between pragmatic language impairments and general language difficulties, autism symptomatology, and clinical outcomes.Methods Participants were younger siblings of children with ASD (high-risk, n = 188) or typical development (low-risk, n = 119) who were part of a prospective study of infants at risk for ASD; siblings without ASD outcomes were included in analyses. Pragmatic language skills were measured via the Language Use Inventory (LUI).ResultsAt 36 months, the high-risk group had significantly lower parent-rated pragmatic language scores than the low-risk group. When defining pragmatic language impairment (PLI) as scores below the 10th percentile on the LUI, 35% of the high-risk group was identified with PLI versus 10% of the low-risk group. Children with PLI had higher rates of general language impairment (16%), defined as scores below the 10th percentile on the Receptive or Expressive Language subscales of the Mullen Scales of Early Learning, relative to those without PLI (3%), but most did not evidence general language impairments. Children with PLI had significantly higher ADOS scores than those without PLI and had higher rates of clinician-rated atypical clinical best estimate outcomes (49%) relative to those without PLI (15%).Conclusions Pragmatic language problems are present in some siblings of children with ASD as early as 36 months of age. As the new DSM-5 diagnosis of Social (Pragmatic) Communication Disorder (SCD) is thought to occur more frequently in family members of individuals with ASD, it is possible that some of these siblings will meet criteria for SCD as they get older. Close monitoring of early pragmatic language development in young children at familial risk for ASD is warranted.
    Journal of Child Psychology and Psychiatry 10/2014; 56(7). DOI:10.1111/jcpp.12342 · 6.46 Impact Factor
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