CREBBP and Down syndrome: AUTS2 syndrome exhibits phenotypic overlap with several other genetic causes of ID, including Rubinstein-Taybi syndrome (CREBBP or EP300) (Fergelot et al., 2016), NONO syndrome (Sewani et al., 2020), TBR1 syndrome (Nambot et al., 2020), and FBRSL1 syndrome (Ufartes et al., 2020).