The Overlap of Autism Symptoms in Children with Williams Syndrome

Background: Williams syndrome (WS) is a neurodevelopmental disorder caused by a deletion of approximately 26 genes on chromosome 7 (7q11.23) (Peoples et al., 2000), and is commonly associated with hyper-sociability. However, despite this pattern of extreme friendliness, individuals with WS display an increased prevalence of autism spectrum disorder (ASD). Previous research investigating the presence of ASD symptoms in WS suggests that individuals with WS display elevations both on assessments measuring symptoms of autism (Lough et al., 2015) as well as gold-standard autism diagnostic assessments (Klein-Tasman, Phillips, Lord, Mervis, & Gallo, 2009).

Objectives: The objective of this study is to investigate the presence of behaviors associated with autism across different symptoms areas (as measured by the treatment scales of the Autism Spectrum Rating Scales; ASRS). Additionally, this study aims to investigate symptoms at the item level, to make recommendations as to which symptoms may best differentiate those with WS who have ASD from those who do not.

Methods: Parents (n=167) of children between 6 and 18 years of age completed survey data online as part of a larger study on ASD, Down syndrome, and WS. This poster aims to focus on the data from the ASD (n=39) and WS (n=45) groups. For this study, parents were asked to report child diagnoses and demographic information as well as complete an autism screener (Social Communication Questionnaire; SCQ) and a dimensional measure of autism symptoms (ASRS). An overall analysis was done to examine autism symptom elevation on the total score of the ASRS. Following this, children in the WS group were then divided into screen positive (n=20) and screen negative groups (n=25) based on whether or not they met the SCQ cut off score of 15.

Results: Overall, the WS group had an ASRS total score significantly higher than the mean score of 50 (M=65.24,SD=6.03), although this was significantly lower than the mean of the ASD group (M= 71.74, SD=5.04; ps<.001). Results comparing ASRS total scores showed that both the WS-screen negative and autism groups, and the WS-screen negative and WS-screen positive groups (ps<.001) were significantly different from one another. However, there was no difference between the autism and WS-screen positive groups. Further analyses using the eight treatment subscales of the ASRS revealed a similar pattern. Analyses at the item level revealed that questions relating to complex social skills (displaying interests in other’s ideas, noticing social cues, understanding the point of view of others), as well as over-reactivity to loud noises may best differentiate these groups.

Conclusions: Results of this study further support previous research suggesting that individuals with WS exhibit elevated symptoms of autism. Although individuals with WS in this sample displayed significantly higher symptoms of autism (as demonstrated by the significantly higher ASRS total score), results suggest that measures such as the ASRS can differentiate between individuals with high vs. low symptoms of autism. Additionally, analyses at the item level suggest potential targets for symptom areas that may best differentiate those with WS who have ASD from those who do not.