The deletion of a single gene in the forebrain neurons of mice causes autistic-like behavior and intellectual disability, scientists report (Mol. Psychiatry 2014, DOI: 10.1038/mp.2014.61). Recent research from the lab of Michele H. Jacob at Tufts University and colleagues had shown that changing the function of a protein called adenomatous polyposis coli (APC) in the brains of mice prevents normal synapse maturation (J. Neurosci. 2010, DOI: 10.1523/jneurosci.0983-10.2010). Now, Jacob’s group has engineered mice with a conditional—in this case, forebrain-specific—knockout of the gene that produces APC. These mice develop hallmark memory and learning impairments, increased repetitive behaviors, and decreased social interest. Scientists have identified myriad genetic disruptions that increase the risk of autism and intellectual disability, but the effect of APC gene loss has implications beyond these conditions in terms of the overall role APC protein plays in the developing brain. The authors found hippocampal changes in the knockout mice that interfered with signaling pathways. They note that these changes are similar to those caused by the mutation of another gene, CHD8, which has also been implicated as a risk factor for autism. “Thus our findings are relevant to autism and intellectual disabilities caused by other human gene mutations, not only APC,” Jacob says.