Thursday, 29 January 2015

Autism spectrum symptomatology in individuals with Down syndrome

I was not surprised to read the findings of the paper from Marie Moore Channell and colleagues [1] (open-access) who "identified patterns of ASD [autism spectrum disorder] symptomatology, measured by the SRS [Social Responsiveness Scale], in individuals with DS [Down syndrome] who do not have comorbid ASD."
You're not going Turbo, are you?

Harking back to the paper by Georgina Warner and colleagues [2] discussed not-so-long-ago on this blog (see here), the idea that various autistic traits might also overlap into other conditions including that of Down's syndrome, is gaining some research momentum at the moment. Whether such overlap will yield further clues regarding the aetiology of [some] autism or feed into the various discussions about the changing autism numbers game are discussions to be had in future times.

Channell et al report results for a small group of children/young adults diagnosed with DS. Their participant cohort originally started at 54 individuals with DS who met various study criteria. This was subsequently boiled down to 46 participants given that: "Eight participants scored above our predetermined cutoff" based on scores on the Social Communication Questionnaire (SCQ) "and were determined to be at risk for a comorbid ASD diagnosis, and they were referred for a full diagnostic evaluation." The authors importantly add that: "this number should not be used as a prevalence estimate of ASD risk in DS." Not yet at least.

The SRS was the primary assessment tool, a parent/caregiver reporting schedule "that asks caregivers about their child’s behavior over the past 6 months" specifically looking at reciprocal social behaviours. As part of the autism screening arsenal, the SRS is doing pretty well by all accounts [3]. That being said, it has it limitations as was recently mentioned [4] following it's use in that broccoli sprout - autism trial (see here).

Anyhow, the results: "In general, scores were elevated relative to the available normative data on typically developing children and adolescents, suggesting the need for normative data on the SRS for syndrome-specific samples such as those with DS." Indeed, the authors go on to suggest that as more is done in this area looking at any overlap between autism and DS: "It is likely that some of the currently used diagnostic measures also will require modification for ease of use and interpretation in the DS population." Too true although I would perhaps stress the idea that something like issues with social reciprocity might be something in need of further investigation in some cases of DS.

I've got little more to say on this issue over and above what has already been said. I'd like to think that once science has progressed a little further in this specific area, it might also turn its attention to the preliminary data reported by Worley and colleagues [5] and further testing of the concept of 'Down Syndrome Disintegrative Disorder' (see here) as one among other potential links between DS and the presentation of autism.

Music, music, music to close: Limahl - Never Ending Story. Sing it with passion...


[1] Channell MM. et al. Patterns of autism spectrum symptomatology in individuals with Down
syndrome without comorbid autism spectrum disorder. Journal of Neurodevelopmental Disorders 2015, 7:5.

[2] Warner G. et al. Autism Characteristics and Behavioural Disturbances in ∼ 500 Children with Down's Syndrome in England and Wales. Autism Res. 2014. March 24. 10.1002/aur.1371

[3] Duvekot J. et al. The Screening Accuracy of the Parent and Teacher-Reported Social Responsiveness Scale (SRS): Comparison with the 3Di and ADOS. J Autism Dev Disord. 2014 Nov 28.

[4] Scahill L. Uncommon use of common measures in sulforaphane trial. PNAS. 2015. Jan 13.

[5] Worley G. et al. Down Syndrome Disintegrative Disorder: New-Onset Autistic Regression, Dementia, and Insomnia in Older Children and Adolescents With Down Syndrome. J Child Neurol. 2014 Nov 3. pii: 0883073814554654.

---------- Marie Moore Channell, B Allyson Phillips, Susan J Loveall, Frances A Conners, Paige M Bussanich, & Laura Grofer Klinger (2015). Patterns of autism spectrum symptomatology in individuals with Down syndrome without comorbid autism spectrum disorder Journal of Neurodevelopmental Disorders : 10.1186/1866-1955-7-5