The CHARGE Study: An Epidemiologic Investigation of Genetic and EnvironmentalFactors Contributing to Autism

摘要

Causes and contributing factors for autism are poorly understood. Evidence suggests that prevalence is rising, but the extent to which diagnostic changes and improvements in ascertainment contribute to this increase is unclear. Both genetic and environmental factors are likely to contribute etiologically. Evidence from twin, family, and genetic studies supports a role for an inherited predisposition to the development of autism. Nonetheless, clinical, neuroanatomic, neurophysiologic, and epidemiologic studies suggest that gene penetrance and expression may be influenced, in some cases strongly, by the prenatal and early postnatal environmental milieu. Sporadic studies link autism to xenobiotic chemicals and/or viruses, but few methodologically rigorous investigations have been undertaken. In light of major gaps in understanding of autism, a large case–control investigation of underlying environmental and genetic causes for autism and triggers of regression has been launched. The CHARGE (Childhood Autism Risks from Genetics and Environment) study will address a wide spectrum of chemical and biologic exposures, susceptibility factors, and their interactions. Phenotypicvariation among children with autism will be explored, as will similaritiesand differences with developmental delay. The CHARGE study infrastructureincludes detailed developmental assessments, medical information, questionnairedata, and biologic specimens. The CHARGE studyis linked to University of California–Davis Center for Children’sEnvironmental Health laboratories in immunology, xenobioticmeasurement, cell signaling, genomics, and proteomics. The goals, studydesign, and data collection protocols are described, as well as preliminarydemographic data on study participants and on diagnoses of thoserecruited through the California Department of Developmental ServicesRegional Center System.