Autistic Traits, Pragmatic Difficulties, and Adaptive Outcomes in Williams Syndrome: A Systematic Narrative Review

Williams syndrome (WS) is a rare neurodevelopmental genetic condition traditionally described as being associated with a highly sociable behavioral profile. However, growing evidence indicates that this characterization may oversimplify the socio-cognitive phenotype, as some individuals with WS exhibit socio-communicative and pragmatic difficulties that may overlap with ASD-related features, although these difficulties should not be interpreted as autism-specific. The present systematic review aimed to investigate the presence of autistic traits in WS, to synthesize evidence on pragmatic and socio-communicative difficulties, and to explore their association with adaptive functioning and, indirectly, adaptive and functional outcomes.

This study follows a systematic search and selection process in accordance with PRISMA 2020 guidelines and employs a systematic review with structured narrative synthesis. A systematic search of PubMed, Scopus, and Web of Science was performed up to December 2022, supplemented by grey literature sources. Nine studies met the predefined inclusion criteria. Due to substantial methodological heterogeneity, findings were synthesized using a structured narrative approach. Study quality was evaluated using adapted criteria addressing research design, sample characteristics, measurement tools, and risk of bias.

The findings suggest that autistic traits may constitute a potentially clinically relevant, though not universal, aspect of the WS phenotype. Pragmatic language difficulties were consistently reported, particularly in relation to conversational management, social reciprocity, and context-appropriate language use. These difficulties appear to function as a key mechanism linking socio-cognitive characteristics with functional outcomes. Patterns of adaptive functioning showed both distinctions from and overlaps with autism spectrum disorder (ASD), especially in communication domains. Available genetic and molecular evidence points to a possible contribution of additional modifying factors for phenotypic variability, with possible phenotypic overlap between WS and ASD, particularly in pragmatic language and adaptive communication.

The evidence supports a multidimensional and spectrum-based conceptualization of socio-communicative functioning in Williams syndrome. Despite strong social motivation, individuals with WS may experience meaningful pragmatic and adaptive challenges, with implications for assessment and intervention. These findings highlight the importance of multidimensional and individualized clinical approaches.