P231: The eXtraordinarY Babies Study: Evolving parental perspectives and priorities while raising a child prenatally diagnosed with sex chromosome trisomy

Introduction: Historically underdiagnosed, infants with sex chromosome trisomies (SCTs) are increasingly being identified through routine prenatal cell-free DNA screening.While numerous studies have investigated varying aspects of parental experiences associated with SCT diagnoses, research describing the perspectives and priorities (P&P) of parents at various stages of childrearing is limited.This study aimed to identify P&P of parents raising a child with prenatally identified SCT (piSCT) at various stages of childhood (birth to 8yo).Methods: The eXtraordinarY Babies Study (NIH/R01HD091251) is a natural history study of 366 children with piSCT, and this sub-study analyzed a crosssectional survey on parental experiences including P&P.Respondents were categorized by the child's SCT diagnosis, diagnostic timing (confirmed before or after birth), and child's age at time of survey completion.Age cohorts were grouped as "Early Childhood" (<3 years), "Preschool" (3-5 years) and "School Age" (6+ years).Respondents answered (yes/no) whether they would have sought genetic testing for their child in the absence of prenatal SCT identification and answered "why?" with open-ended responses that were thematically analyzed and relationally grouped.Respondents ranked the current importance of 13 topics using an ordinal scale (1-100), including 5 health topics, 6 neurodevelopmental topics, and 2 disclosure topics.Results were analyzed with descriptive statistics (mean, median [IQR], proportions).Results: One hundred ninety-five surveys were completed (53.3%), mostly by mothers (92.8%).Almost all (98.5%) children were initially identified by prenatal cfDNA screening.Approximately half (52.1%) of diagnoses after cfDNA were deferred to postnatal cytogenetic confirmation.Karyotypes included 47,XXY (n=100, 51.3%), 47,XXX (n=57, 29.2%), 47,XYY (n=38, 19.5%).Median child age at survey completion was 3.7 years [1.9, 4.9], with cohorts of Early Childhood (n=69, 35.4%),Preschool (n=96, 49.2%) and School age (n=30, 15.4%).While more than a third (35.1%) of respondents reported the child's history to include at least one developmental delay, medical problem, or physical difference associated with SCT, only 23.9% of these respondents reported they would have advocated for genetic testing without a known SCT diagnosis, mostly (68.7%) based on a history of global delays and/or complex medical problems.Of the 13 ranked priority categories, only 6 categories were consistently highly prioritized: "DM"= Developmental milestones (language, motor, cognitive), "L/S"= Learning and/or school, "MH"= Mental health (anxiety, depression, other), "A/F"= Attention and Focus, "B"=Behavior, and "SS"= social skills (friendships and/or risk for autism).Current top 3 priorities (highest mean ratings): By SCT: