The clinical picture of children with autistic features and developmental delay is partly similar to that of schizophrenia with leading negative symptoms and severe neurocognitive deficit; neuroimaging studies show an increased volume of the cerebral ventricles in children with Pitt–Hopkins syndrome [28], so the contribution of polymorphic variants of the TCF4 gene to the formation of independent clinical, cognitive, and neuroimaging phenotypes appears systemic. This evidence concerns the gene TCF4 and Global developmental delay.