Genetic predisposition to autism may involve both differences in the coding regions of DNA (genomic regions encoding RNAs which are eventually translated into proteins) and changes in the regulation of gene expression, though the coding regions of DNA are unaffected. A recently discovered mechanism for the regulation of gene expression is non-coding RNAs (RNAs which do not get translated into proteins). Non-coding RNAs may regulate the translation of other RNAs to proteins. Changes in expression of these non-coding RNAs could potentially be involved in the development of autism. This study aims to characterize the non-coding RNAs present in autistic individuals compared to normal individuals. Researchers will use microarray technology capable of measuring the levels of thousands of individual RNAs to identify which non-coding RNAs are expressed at different levels in blood cells from autistic versus non-autistic subjects. Examining non-coding RNAs is a novel approach to discovering the biological mechanisms underlying autism, and may identify novel drug targets for the treatment and prevention of autism.