By Admin, on 25 January 2021
Comorbidity Williams syndrome and Autism spectrum disorders
Comorbidity is the presence of a developmental disorder co-occurring with another one. It is often claimed that those with Williams syndrome (WS) and those with Autism spectrum disorders (ASD) show opposite social and communication difficulties. Yet, the comorbidity between WS and ASD is higher than expected, even though the exact rate of dual diagnosis is currently unclear. A number of parents have asked me how a comorbid diagnosis for ASD in WS can be made. Therefore, below I have outlined some of the similarities and differences that are commonly observed in those with WS and ASD (but this list is not exhaustive). Although all children are different, these are the typical behaviours that one would observe for each developmental disorder. As you can see from the table, there is quite a lot of overlap between the two disorders, which makes it harder to make a comorbid diagnosis of ASD and WS.
|Delayed verbal abilities (delayed first word)||Delayed verbal abilities (delayed first word)|
|Poor grammatical comprehension||Poor grammatical comprehension|
|Takes language literally||Takes language literally|
|Sensory processing difficulties||Sensory processing difficulties|
|Likes repetition and structure||Likes repetition and structure|
|General anxiety||General anxiety|
|Delayed motor development||Delayed motor development|
|Local processing bias||Local processing bias|
|Good visuo-spatial abilities (puzzles)||Poor visuo-spatial abilities (puzzles)|
|High social anxiety||Low social anxiety|
|Low social approach||High social approach|
|Eye contact avoidance||Eye contact seeking/ staring at faces|
|Stereotyped language||Some stereotyped language but less|
|Atypical intonation||Generally typical intonation|
|Echolalia||Some echolalia but limited|
|Does not respond to name||Responds to name|
|Poor imaginary play||Good imaginary play|
As can be seen from the table children with WS often show socio-communication difficulties that overlap with ASD. However, those with WS who receive a dual diagnosis for ASD show more features that are typically only seen in ASD, especially eye contact avoidance, atypical intonation, and low social approach.
Klein-Tasman BP, Phillips KD, Lord CE, Mervis CB, Gallo F. Overlap with the Autism Spectrum in Young Children with Williams Syndrome. Journal of developmental and behavioral pediatrics : JDBP. 2009;30(4):289-299. doi:10.1097/DBP.0b013e3181ad1f9a.
Asada K, Itakura S. Social Phenotypes of Autism Spectrum Disorders and Williams Syndrome: Similarities and Differences. Frontiers in Psychology. 2012;3:247. doi:10.3389/fpsyg.2012.00247.