The Study to Explore Early Development (SEED) is a multi-site case-control study designed to explore the relationship between autism spectrum disorder (ASD) phenotypes and etiologies. The goals of this paper are to (1) describe the SEED algorithm that uses the Autism Diagnostic Interview-Revised (ADI-R) and Autism Diagnostic Observation Schedule…

Efforts to understand the causes of autism spectrum disorders (ASDs) have been hampered by genetic complexity and heterogeneity among individuals. One strategy for reducing complexity is to target endophenotypes, simpler biologically based measures that may involve fewer genes and constitute a more homogenous sample. A genome-wide association…

Objective: Many investigators now routinely classify children with fragile X syndrome (FXS) according to whether or not they also meet diagnostic criteria for autism. To determine whether this classification is appropriate, we examined the profiles of autistic behaviors shown by boys and girls with FXS. Method: Individuals with FXS, aged 5 to 25…

Background: Autism is rarely diagnosed before three years of age despite evidence suggesting prenatal abnormalities in neurobiological processes. Little is known about when or how development becomes disrupted in the first two years of life in autism. Such information is needed to facilitate early detection and early intervention. Methods: This…