Any neurodevelopmental disorder in which the cause of the disease is a monoallelic gain-of-function variation in the PIP5K1C gene leading to increased levels of phosphatidylinositol 4,5 bisphosphate. This disorder is characterized by intellectual disability, motor and speech delay, microcephaly, seizures, visual and ocular abnormalities, and craniofacial dysmorphic features. The disease is Monarch Disease Ontology entry MONDO_1010145 (PIP5K1C-related neurodevelopmental disorder).