This study is looking for abnormal gene expression patterns in the brains of individuals with autism. One way that genes are turned off is through DNA methylation: an enzyme places a methyl group onto certain sequences of DNA, thus flagging those genes for silencing. Thus, by examining the methylation status of genes, one can tell whether the gene is turned off or not. Researchers will examine the methylation patterns of genes taken from post-mortem brain tissue of autistic individuals and compare them to tissue from controls. The primary tool for analysis will be DNA microarrays ("gene chips"), which allow a genome-wide scan.