Intellectual Developmental Disorder with Behavioral Abnormalities and Craniofacial Dysmorphism with or Without Seizures, also known as neurodevelopmental disorder with macrocephaly and with or without seizures, is related to visual epilepsy and hypotonia. An important gene associated with Intellectual Developmental Disorder with Behavioral Abnormalities and Craniofacial Dysmorphism with or Without Seizures is PHF21A (PHD Finger Protein 21A). Related phenotypes are intellectual disability and global developmental delay