Sex chromosome trisomies (SCT) are among the most common chromosomal duplicationsin humans. Due to recent technological advances in non-invasive screening, SCTcan already be detected during... Show moreSex chromosome trisomies (SCT) are among the most common chromosomal duplicationsin humans. Due to recent technological advances in non-invasive screening, SCTcan already be detected during pregnancy. This calls for more knowledge about thedevelopment of (young) children with SCT. This review focused on neurocognitivefunctioning of children with SCT between 0 and 18 years, on domains of global intellectualfunctioning, language, executive functioning, and social cognition, in order toidentify targets that could benefit from early treatment.Online databases were used to identify peer-reviewed scientific articles using specificsearch terms. In total 18 studies were included. When applicable, effect sizes werecalculated to indicate clinical significance.Results of the reviewed studies show that although traditionally, the focus has been onlanguage and intelligence (IQ) in this population, recent studies suggest that executivefunctioning and social cognition may also be significantly affected already in childhood.These findings suggest that neuropsychological screening of children diagnosed withSCT should be extended, to also include executive functioning and social cognition.Knowledge about these neurocognitive risks is important to improve clinical care andhelp identify targets for early support and intervention programs to accommodatefor the needs of individuals with SCT. Show less