In previous studies, researchers identified a novel single nucleotide polymorphism (SNP), a variation in the DNA sequence, in the DACT1 gene locus in autism patients. The researchers hypothesize that this SNP, which tracks with the diagnosis of autism in an affected family, alters Dact1 protein function in developing neurons to cause the disease. A model system using a knock-out mouse and a cell line relevant to autism pathogenesis has been established to study the function of the Dact1 protein. In this study, these mouse and cell model systems will be used to assess whether the loss of this protein affects neural development and whether the autism-variant of the protein has different biochemical or functional properties than the typical, wild type protein. Examining the effects of the SNP in the DACT1 gene could further the understanding of the biological mechanisms that underlie autism.