ABSTRACT
Williams syndrome (WS) is a rare genetically based developmental disorder with a unique cognitive and behavioural profile. At the cognitive level, individuals with WS commonly have mild to moderate intellectual disability with relative strengths in language, short-term verbal memory and face processing accompanied by more profound weaknesses in visuospatial construction, drawing, number processing and visuomotor integration. This chapter first reviews studies on clinical symptoms and comorbidities and then turn to studies of genotype-phenotype correlations using atypical/partial deletion cases as illustrative examples. It discusses how patterns of strengths and weaknesses in the neuropsychological profile are broadly consistent with the verbal and spatial dissociation in WS, and then outlines how poor planning and visuomotor integration impact on gait and motor features in WS. The chapter then reviews studies of atypical structure, neural activation and functional connectivity within and between key regions underlying the unique cognitive and behavioural phenotype in WS. It briefly discusses the limited pharmacological and behavioural interventions.
