Portrayals of individuals with Williams syndrome (WS), a genetic disorder caused by a microdeletion of ~25 genes on chromosome 7q11.23, have reached the general public through a variety of media formats. These descriptions are often paradoxical in nature with individuals with WS repeatedly described as demonstrating near-normal language despite the presence of significant intellectual disability and as being extremely sociable and friendly in spite of their seemingly limited understanding of basic social norms. While this depiction of WS served to attract the interest of basic-science researchers, the results of subsequent studies have provided a more nuanced view. For example, rather than across-the-board "near-normal" language, children with WS demonstrate relative strengths in concrete vocabulary and verbal short-term memory, grammatical abilities at the level expected for general intellectual ability, and considerable weakness in relational/conceptual language and pragmatics (social use of language). To provide a more thorough characterization of the WS behavioral phenotype, we summarize recent findings related to intellectual ability, language development, memory development, executive function development, adaptive behavior skills, and behavior as it relates to learning by children with WS. Finally, we briefly discuss intervention approaches that may help children with WS to achieve their full potential.

The ability to organize information detected by our senses ("sensory modulation") allows us to act or respond effectively to situations encountered, facilitating learning, social behavior, and day to day functioning. We hypothesized that children with Williams syndrome (WS) would demonstrate symptoms of poor sensory modulation and that these sensory modulation abnormalities contribute to the phenotype. Participants were 78 children with WS aged 4.00 -10.95 years. Based on parent ratings on the Short Sensory Profile [SSP; , most children were classified as having definite sensory modulation issues. Cluster analysis identified the presence of two clusters varying in level of sensory modulation impairment. Children in the high impairment group demonstrated poorer adaptive functioning, executive functioning, problems behaviors, and more difficult temperaments than children in the low impairment group.

Multilevel modeling was used to address the longitudinal stability of standard scores (SSs) measuring intellectual ability for children with Williams syndrome (WS). Participants were 40 children with genetically-confirmed WS who completed the Kaufman Brief Intelligence Test-2 (KBIT-2; Kaufman & Kaufman, 2004) 4–7 times over a mean of 5.06 years. Mean age at first assessment was 7.44 years (range: 4.00–13.97 years). On average KBIT-2 Composite IQ, Verbal SS, and Nonverbal SS were stable from 4–17 years, although there were significant individual differences in intercept (Composite IQ, Verbal SS, Nonverbal SS) and slope (Composite IQ, Nonverbal SS). Maternal education was significantly related to Verbal SS intercept. No significant sex differences were obtained. Implications for studies of genotype/phenotype correlations in WS are discussed.

Purpose-This project was designed to identify relative strengths and weaknesses in vocabulary ability for children with Williams syndrome (WS) and to demonstrate the importance of stringent matching criteria for cross-group comparisons.Methods-Children with WS and typically developing (TD) children completed standardized assessments of intellectual and language ability. Children with WS also completed a visuospatial construction ability assessment.Results-Study 1: Concrete and relational vocabulary standard scores were significantly lower for 5 -7-year-olds with WS than for TD children. Children with WS earned significantly higher standard scores for concrete than for relational vocabulary. When groups were stringently matched for relational vocabulary size, children with WS did not evidence a specific weakness in spatial vocabulary. Study 2: Standard scores for relational vocabulary were similar to those for visuospatial construction ability for 5 -7-year-olds with WS. Study 3: 9 -11-year-olds with WS demonstrated very limited relational vocabulary ability; relational vocabulary ability at 5 -7 years was highly correlated with later relational language ability.Conclusions-Concrete vocabulary is a relative strength for children with WS; relational vocabulary ability is very limited and is at about the level of visuospatial construction ability. Accurate determination of group comparison results depends on stringent group matching. KeywordsWilliams syndrome; intellectual disability; language acquisition; vocabulary; visuospatial construction Williams syndrome (WS) is a neurodevelopmental disorder caused by the deletion of ~25 genes on chromosome 7q11.23 (Hillier et al., 2003;Osborne, 2006). The WS deletion, which has a prevalence of 1/7500 (Strømme, Bjørnstad, & Ramstad, 2003), results in a characteristic pattern of physical characteristics, including a distinctive facial appearance, cardiovascular disease (especially supravalvar aortic stenosis), connective tissue abnormalities, and growth deficiency (see Mervis & Morris, 2007 for a review). Individuals with WS typically have mild to moderate intellectual disability, but some individuals have low average to average intellectual ability and a smaller minority have severe intellectual disability. WS is associated with a specific cognitive profile, including relative strengths in verbal short term memory and in language and severe weakness in visuospatial construction (Mervis et al., 2000). The personality profile was one of the first diagnostic clues provided for WS (Bennett et al., 1978;Cassidy & Morris, 2002) and includes overfriendliness, gregariousness, and high levels of empathy, with an undercurrent of anxiety (Klein-Tasman & Mervis, 2003). The psychiatric profile includes ADHD, specific phobia, and generalized anxiety disorder beginning in early adolescence (Leyfer et al., 2006).WS came to the attention of researchers in the United States because of the pioneering work of Ursula Bellugi (e.g., Bates, 1990;Bellugi, Marks, Bihrle, & Sabo, 1988) arguin...

Purpose This study examined the ability of preschoolers with Williams syndrome (WS) or Down syndrome (DS) to infer communicative intent as expressed through gestures (pointing and eye gaze shift). Methods Participants were given a communicative or non-communicative cue involving pointing or gaze shifting in the context of a hiding game. Each child completed four conditions formed by crossing Communicative style (communicative vs. non-communicative) and Gesture (point vs. gaze shift). Results At the group level, children in both groups located the toy significantly more often than expected by chance in the communicative condition but performed at chance in the non-communicative condition. Children in both groups were more likely to infer communicative intent when pointing rather than gaze shifting was used. Individually, despite significantly lower DQ and language standard scores, significantly more children with DS than with WS successfully used the experimenter’s communicative gestures. Conclusions At the group level, preschoolers with WS or DS were able to comprehend the communicative intent expressed by pointing and gazing gestures in a table-top task. Children with DS evidenced significantly stronger pragmatic skills than did children with WS, providing further evidence that children with WS have more difficulty with socio-communication than expected for CA or cognitive/language ability.