Environmental Factors in Autism

ISEE-206

Abstract:

Autism is a severe lifelong developmental disorder involving deficits in social reciprocity and communication, along with stereotypic or limited interests or behaviors. The causes are largely unknown, although the high familial recurrence rate and high rate of concordance among monozygotic twins support a strong role for genes. Nevertheless, both genetic and environmental factors are likely to contribute, and the existing literature provides evidence for both biological (rubella) and chemical (thalidomide) agents in the etiology of autism, where exposure occurred in utero. We have launched The Childhood Autism Risks from Genetics and the Environment (CHARGE) Study to examine a broad range of environmental factors in relation to early childhood development. This case-control study is enrolling three groups: children with autism, children with developmental delay or retardation, and children from the general population. The first two groups are enrolled through California's state-wide system of Regional Centers that coordinate services for eligible residents. General population controls are frequency-matched by age, gender, and Regional Center catchment area to the autism cases. Children with autism are administered the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule-Generic (ADOS-G); children in the other two groups are administered the Social Communication Questionnaire, and if they score poorly then they are tested for autism. For all children, the protocol includes the Mullen Scales of Early Learning, the Vineland Adaptive Behavior Scales, a medical examination, a dysmorphology assessment, and instruments to assess gastrointestinal symptoms, sleep disorders, and family history of auto-immune diseases. An exposure questionnaire obtains sociodemographic, lifestyle, residential, and occupational information; maternal reproductive history, as well as diet, illnesses, and medications during pregnancy; garden, home and pet pesticide use; and child's medical and early life exposures. Blood, urine, and hair specimens are obtained from the child, parents and siblings. These are being used to characterize immunologic profiles, internal body burdens of metals over time, persistent organics and their metabolites, and gene expression, especially of P450 enzymes. Preliminary results will be presented. Supported by NIEHS: 1P01-ES11269.