A neurodevelopmental disorder caused by a mutation in TCF gene, characterized by impaired intellectual development with speech difficulties and behavioral abnormalities, most commonly autism spectrum disorder (ASD), defects in attention, and/or hyperactivity. The disease is Monarch Disease Ontology id MONDO_0032745 (developmental delay with variable intellectual impairment and behavioral abnormalities). Also known as: DDVIBA, TCF20-related disorder, TCF20-related syndrome.