A neurodevelopmental disorder caused by heterozygous variants in SETD2 and characterized by intellectual disability or developmental delay, motor delay, speech delay, hypotonia, autism spectrum disorder, attention deficit disorder, and sometimes features such as macrocephaly, overgrowth, and dysmorphic features. The disease is SETD2-related neurodevelopmental disorder without or with macrocephaly/overgrowth (MONDO_0800477).