Sex chromosome trisomies (SCTs) are characterized by an extra X- or Y-chromosome(XXX, XXY, XYY). The present study aims to investigate early signs of social communica-tion and social emotional development in veryyoung children with SCT. Thirty-four chil-dren with SCT (aged 12–24 months) were included in this study, as well as 31 age-matched controls. Social communication was measured with structured behavior observa-tions according to the Early Social Communication Scales, and social emotional develop-mental level with the Bayley Social Emotional parental questionnaire. Recruitment andassessment took place in the Netherlands and in the United States. On average, 12–24-montholdchildrenwithSCTshoweddifficulties with early social communication, moreso in responding to others as compared to initiating social communications. During socialinteractions, children with SCT made less frequent eye contact, compared to controls.Also, difficulties in acquiring social emotional milestones were found in 1-year old childrenwith SCT, with 44% of the children having socialemotional vulnerabilities in the borderlineor extremely low range, compared to typicallydeveloping children. In this cohort, no sig-nificant predictive effects of karyotype-subtype (XXX, XXY, XYY) were found. Alreadyfrom a very early age, SCT can be associated with increased risk for vulnerabilities in adap-tive social functioning. These findings suggest that SCT impact the maturation of the socialbrain already from an early age, and stress the importance of early monitoring and (pre-ventive) support early social development in young children with SCT.Development Psychopathology in context: clinical setting
