The researchers hypothesize that more patients dianosed with autism spectrum disorders have mutations or epimutations involving MECP2, genes within chromosome 15q11-q13, and the loci causing fragile X syndrome and tuberous sclerosis than is currently recognized. They also hypothesize that genes that interact with MECP2 and UBE3A are candidate genes for mutation or epimutation causing autism. Careful studies of autism patients for changes in these loci have already led to additional insights into autism, especially for MECP2 and 15q11-q13. The study includes in-depth genotype/phenotype and epigenotype/phenotype correlations in autistic patients with known abnormalities in these genes and regions with the goal of achieving further insights into more common forms of autism. In addition, the study will anlayze typical autism patients for novel forms of mutationor epimutation involving MECP2, genes within 15q11-q13, or other genes.