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Infant siblings and the investigation of autism risk factors

Craig J Newschaffer1, Lisa A Croen2, M Daniele Fallin3, Irva Hertz-Picciotto4, Danh V Nguyen4, Nora L Lee1*, Carmen A Berry3, Homayoon Farzadegan3, H Nicole Hess5, Rebecca J Landa6, Susan E Levy7, Maria L Massolo2, Stacey C Meyerer3, Sandra M Mohammed4, McKenzie C Oliver4, Sally Ozonoff8, Juhi Pandey7, Adam Schroeder4 and Kristine M Shedd-Wise4

Author Affiliations

1 Department of Epidemiology and Biostatistics, Drexel School of Public Health, 1505 Race Street, Mail Stop 1033, Philadelphia, PA 19102, USA

2 Kaiser Permanente Division of Research, 2000 Broadway, Oakland, CA 94612, USA

3 Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe Street, Baltimore, MD 21205, USA

4 Department of Public Health Sciences, University of California, Davis, CA 95616, USA

5 Kaiser Permanente San Jose Medical Center, 6620 Via Del Oro, San Jose, CA 95119, USA

6 Kennedy Krieger Institute, 3901 Greenspring Avenue, 2nd Floor, Baltimore, MD 21211, USA

7 Center for Autism Research, The Children's Hospital of Philadelphia, 3535 Market Street, Suite 860, Philadelphia, PA 19104, USA

8 The MIND Institute, UC Davis Medical Center, 2825 50th Street, Sacramento, CA 95817, USA

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Journal of Neurodevelopmental Disorders 2012, 4:7  doi:10.1186/1866-1955-4-7

Published: 18 April 2012


Infant sibling studies have been at the vanguard of autism spectrum disorders (ASD) research over the past decade, providing important new knowledge about the earliest emerging signs of ASD and expanding our understanding of the developmental course of this complex disorder. Studies focused on siblings of children with ASD also have unrealized potential for contributing to ASD etiologic research. Moving targeted time of enrollment back from infancy toward conception creates tremendous opportunities for optimally studying risk factors and risk biomarkers during the pre-, peri- and neonatal periods. By doing so, a traditional sibling study, which already incorporates close developmental follow-up of at-risk infants through the third year of life, is essentially reconfigured as an enriched-risk pregnancy cohort study. This review considers the enriched-risk pregnancy cohort approach of studying infant siblings in the context of current thinking on ASD etiologic mechanisms. It then discusses the key features of this approach and provides a description of the design and implementation strategy of one major ASD enriched-risk pregnancy cohort study: the Early Autism Risk Longitudinal Investigation (EARLI).

Autism; Cohort; Epidemiology; Pregnancy; Prospective; Sibling; Study Design