Congenital or postnatal overgrowth syndrome most often in height and occipitofrontal circumference with variable delayed motor and cognitive development. other associated features include advanced bone age, seizures, neonatal jaundice; hypotonia; and scoliosis. it is also associated with increased risk of developing neoplasms in adulthood. mutations in the nsd1 protein and its haploinsufficiency are associated with the syndrome.