This study, performed by researchers at the University of Pennsylvania, analyzed the level of gene expression in children with autism, compared with a control group. The researchers hypothesized that the variability in the pattern of the overall of gene expression levels would be associated with variability in hippocampal-dependent behaviors, which include short-term memory and spatial navigation. Additionally, the group tested whether increased paternal age was associated with variance of gene expression. A decrease in the variability of gene expression levels was associated with the diagnosis of autism and increased paternal age. The research team believes this change to be caused by the down-regulation of gene expression pathways involved in protein synthesis regulation in the blood of children with autism and children with older fathers. Thus, the researchers concluded that alterations at the gene level of gene expression regulation are related to autism and increased paternal age.