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Beyond Autism: A Baby Siblings Research Consortium Study of High-Risk Children at Three Years of Age

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Abstract

Objective

First-degree relatives of persons with an autism spectrum disorder (ASD) are at increased risk for ASD-related characteristics. As little is known about the early expression of these characteristics, this study characterizes the non-ASD outcomes of 3-year-old high-risk (HR) siblings of children with ASD.

Method

Two groups of children without ASD participated: 507 HR siblings and 324 low-risk (LR) control subjects (no known relatives with ASD). Children were enrolled at a mean age of 8 months, and outcomes were assessed at 3 years. Outcome measures were Autism Diagnostic Observation Schedule (ADOS) calibrated severity scores, and Mullen Verbal and Non-Verbal Developmental Quotients (DQ).

Results

At 3 years, HR siblings without an ASD outcome exhibited higher mean ADOS severity scores and lower verbal and non-verbal DQs than LR controls. HR siblings were over-represented (21% HR versus 7% LR) in latent classes characterized by elevated ADOS severity and/or low to low-average DQs. The remaining HR siblings without ASD outcomes (79%) belonged to classes in which they were not differentially represented with respect to LR siblings.

Conclusions

Having removed a previously identified 18.7% of HR siblings with ASD outcomes from all analyses, HR siblings nevertheless exhibited higher mean levels of ASD severity and lower levels of developmental functioning than LR children. However, the latent class membership of four-fifths of the HR siblings was not significantly different from that of LR control subjects. One-fifth of HR siblings belonged to classes characterized by higher ASD severity and/or lower levels of developmental functioning. This empirically derived characterization of an early-emerging pattern of difficulties in a minority of 3-year-old HR siblings suggests the importance of developmental surveillance and early intervention for these children.

Section snippets

Participants

Participant data were obtained from nine member sites whose recruitment procedures and common assessment measures allowed for data pooling. Institutional review board approval was obtained to collect and analyze de-identified data from all sites. Infants were enrolled at a mean age of 8.04 months (SD = 4.00 months) and were administered complete clinical evaluations at a mean age of 37.10 months (SD = 2.32 months). All children with an ASD, that is, children who met both clinical judgment and

Preliminary Analyses

Descriptive Statistics. There were no group differences in race (white versus other) or sex (Table 1). There was a significant group difference for maternal education (X2 = 6.21, df = 1, p<.05), with a higher proportion of mothers in the LR group having college or graduate degrees. HR siblings were enrolled slightly later than children in the LR group (F1,830 = 36.92, p<.001) , and were more likely to have received module 1 rather than module 2 of the ADOS at outcome (χ2 = 10.65, df = 1, p<

Discussion

This is the first large-scale examination of ASD behavioral characteristics and developmental functioning in HR siblings without an ASD outcome. Objective, standardized assessments indicated that, as a group, HR siblings had slightly higher ASD severity scores, lower levels of verbal functioning, and slightly lower levels of nonverbal functioning than LR comparison children. A latent class analysis distinguished groups of HR and LR children with similar 3-year outcomes. Although HR siblings

References (47)

  • D.H. Geschwind

    Genetics of autism spectrum disorders

    Trends Cogn Sci

    (2011)
  • L. Zwaigenbaum et al.

    Behavioral manifestations of autism in the first year of life

    Int J Dev Neurosci

    (2005)
  • R. Arden et al.

    Sex differences in variance of intelligence across childhood

    Personal Indiv Diff

    (2006)
  • Autism and Developmental Disabilities Monitoring (ADDM) Network. Prevalence of Autism Spectrum Disorders—Autism and...
  • R.J. Landa et al.

    Social and communication development in toddlers with early and later diagnosis of autism spectrum disorders

    Arch Gen Psychiatry

    (2007)
  • S. Shumway et al.

    Brief report: Symptom onset patterns and functional outcomes in young children with autism spectrum disorders

    J Autism Developmental Disorders

    (2011)
  • S. Ozonoff et al.

    Recurrence risk for autism spectrum disorders: a Baby Siblings Research Consortium study

    Pediatrics

    (2011)
  • J. Piven

    Genetic liability for autism: the behavioural expression in relatives

    Int Rev Psychiatry

    (1999)
  • S. Folstein et al.

    Infantile autism: a genetic study of 21 twin pairs

    J Child Psychol Psychiatry

    (1977)
  • A. Pickles et al.

    Variable expression of the autism broader phenotype: findings from extended pedigrees

    J Child Psychol Psychiatry Allied Discipl

    (2000)
  • K. Toth et al.

    Early social, imitation, play, and language abilities of young non-autistic siblings of children with autism

    J Autism Dev Disord

    (2007)
  • W. Stone et al.

    Early social-communicative and cognitive development of younger siblings of children with autism spectrum disorders

    Arch Pediatr Adolesc Med

    (2007)
  • N. Garon et al.

    Temperament and its relationship to autistic symptoms in a high-risk infant sib cohort

    J Abnorm Child Psychol

    (2009)
  • N. Yirmiya et al.

    Cognitive and verbal abilities of 24- to 36-month-old siblings of children with autism

    J Autism Dev Disord

    (2007)
  • L. Zwaigenbaum et al.

    Sex differences in children with autism spectrum disorder identified within a high-risk infant cohort

    J Autism Dev Disord

    (2012)
  • R.J. Landa et al.

    Latent class analysis of early developmental trajectory in baby siblings of children with autism

    J Child Psychol Psychiatry

    (2012)
  • I. Gamliel et al.

    Developmental trajectories in siblings of children with autism: cognition and language from 4 months to 7 years

    J Autism Dev Disord

    (2009)
  • A.J. Schwichtenberg et al.

    Can family affectedness inform infant sibling outcomes of autism spectrum disorders?

    J Child Psychol Psychiatry

    (2010)
  • S. Ozonoff et al.

    A prospective study of the emergence of early behavioral signs of autism

    J Am Acad Child Adolesc Psychiatry

    (2010)
  • J.N. Constantino et al.

    Sibling recurrence and the genetic epidemiology of autism

    Am J Psychiatry

    (2010)
  • J. Constantino et al.

    Autistic social impairment in the siblings of children with pervasive developmental disorders

    Am J Psychiatry

    (2006)
  • J. Hallmayer et al.

    Genetic Heritability and shared environmental factors among twin pairs with autism

    Arch Gen Psychiatry

    (2011 2011)
  • Lord et al.

    The Autism Diagnostic Observation Schedule–Generic: a standard measure of social and communication deficits associated with the spectrum of autism

    J Autism Dev Disord

    (2000)
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    Autism Speaks provided funding for the creation of a Baby Siblings Research Consortium (BSRC) database and data analysis (G.S.Y.). Data collection was supported by the National Institutes of Health (NIH) grants MH068398 (S.O., S.J.R., G.S.Y.), NIH DC10290 (A.C.), NIH HD047417 (D.M.), NIH HD057284 (W.L.S., D.M.), NIH HD042541 (J.N.C.), HD052804 (K.D., L.J.C.), HD54979 (J.M.I.), NIH U54-MH066417 and MH059630 (R.J.L.), NIH U54-MH068172 (M.S., T.H.), and NIH HD043292 (W.L.S.); the United States–Israel Binational Science Foundation 94-66/3 and 97-00073 (M.S.); and the Canadian Institute for Health Research 62924 and 102665 (L.Z., S.B.).

    Supplemental material cited in this article is available online.

    Dr. Gregory S. Young served as the statistical expert for this research.

    The authors thank Alycia Halladay, Ph.D., of Autism Speaks, for tremendous organization support, and Batya Elbaum, Ph.D., of the University of Miami, for editorial assistance.

    Disclosure: Dr. Carter has received royalties from the Infant Toddler Social Emotional Assessment (ITSEA). Dr. Charman has received grant or research support from the UK Medical Research Council, the European Science Foundation, Autistica, Research Autism, the Autism Education Trust, and Autism Speaks. He has received royalties from Guilford Press and Sage. Dr. Constantino has received grant or research support from NIH, the National Institute of Child Health and Human Development, the National Institute of Mental Health, the Department of Health and Human Services, Autism Speaks, and the Centers for Disease Control and Prevention. He has received royalties for the authorship of assessment tools from Western Psychological Services (SRS). Dr. Rogers is the author of Early Start Denver Model for Young Children With Autism, published by Guilford Press, from which she has received royalties. Dr. Sigman is deceased. Drs. Messinger, Young, Ozonoff, Dobkins, Zwaigenbaum, Landa, Stone, Hutman, Carver, Bryson, Iverson, and Strauss report no biomedical financial interests or potential conflicts of interest.

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