Given previous observations that animal models and patients with schizophrenia, autism, or intellectual disability harbor aberrant neuronal connectivity and synaptic development (Kaufmann and Moser, 2000; Hutsler and Zhang, 2010; Kulkarni and Firestein, 2012; Bakhshi and Chance, 2015), we sought to investigate the impact of increased p110δ expression on neuronal developmental including morphological measures of neuronal viability, axonal outgrowth, dendritic complexity, and dendritic spine formation and maturation in vitro. Here, PIK3CD is linked to autism.