Investigating Behaviour in Silver-Russell Syndrome: Research Summary

by Chloe Lane, Louisa Robinson, Megan Freeth

 For the past year, we have been conducting a study to investigate behavioural characteristics observed in SRS. The study involved a play session/semi-structured interview which was used to observe how children play with different toys, their ability to tell stories and how they communicated with the researcher. For older children and adults, this was an informal conversation to find out about things such as friendships, hobbies and school/work. The study also involved completing a few different activities to assess skills such as language, memory and problem solving. We finished visiting families in October 2018 and in total, we saw 15 individuals with an mUPD7 diagnosis and 18 individuals with an 11p15 diagnosis. This was slightly more than our original target so we are extremely grateful to all of the families who took part in the study and made it possible. The findings from the study have been written for publication in a scientific journal and as soon as the article is published, we will share this with the CGF. Below is a summary of the main findings from the study.

Autistic behaviours are broadly defined as having difficulty with social interaction and social communication, as well as displaying restricted interests and repetitive behaviours. Previous research has indicated that autistic traits may be more common in SRS than in the general population. In particular, it has been suggested that individuals with an mUPD7 diagnosis are more likely to display autistic traits, with some also having a diagnosis of an autism spectrum disorder (ASD). Although this research has indicated that autistic traits are common in SRS, the nature of these behaviours has not been assessed in a systematic way, using standardised measures. Therefore, the aim of our research was to use both a gold-standard behavioural assessment and a questionnaire, completed by a parent/caregiver, to identify autistic traits associated with SRS 11p15 and SRS mUPD7. A further aim of the study was to assess cognitive abilities associated with SRS 11p15 and SRS mUPD7. Autistic traits were assessed using the Social Responsiveness Scale, second edition (SRS-2) and the Autism Diagnostic Observation Schedule, second edition (ADOS-2). Cognitive abilities were assessed using the British Ability Scales, third edition (BAS3). Participants in the 11p15 group ranged in age from 4 – 15 years and in the mUPD7 group, participants ranged in age from 8 – 28 years.

In relation to autistic traits, the findings from the questionnaire (SRS-2) indicated that 53% of the mUPD7 participants and 45% of the 11p15 participants were reported by their family member as having some difficulty with social skills and restricted interests/repetitive behaviours in daily contexts. The level of difficulty with these behaviours varied between the groups, with 38% of the mUPD7 participants reported as having significant difficulty with these behaviours, compared with 11% of the 11p15 participants. Furthermore, the level of difficulty with social skills did not differ between the groups but the mUPD7 group were reported as displaying more difficulty with restricted interests/repetitive behaviours. Overall, this suggests that autistic traits are more common in both SRS mUPD7 and SRS 11p15 than in the general population but that these traits seems to be more pronounced in SRS mUPD7. In particular, these individuals may struggle with restricted interests and repetitive behaviours.

Autistic traits were also assessed using an in-person assessment (ADOS-2). The ADOS-2 provides an opportunity to observe whether an individual displays difficulty with social skills and restricted interests/repetitive behaviours in a semi-structured context. The findings from this assessment supported the findings from the SRS-2, with 33% of the mUPD7 group and 11% of the 11p15 group displaying autistic behaviours during the assessment. Once again, this indicates that individuals with an mUPD7 diagnosis are more likely to have difficulty with autistic behaviours. It is important to note that in both groups, a number of individuals did not display these behaviours. Therefore, clinicians should be aware of this increased likelihood of ASD in SRS but consider on an individual basis, whether a full assessment for ASD would be appropriate.

Cognitive abilities were also assessed in order to identify the overall ability of individuals with SRS and whether individuals show consistent strengths and difficulties with specific aspects of learning. Each participant completed several different activities which provided a general conceptual ability (GCA) score. This is equivalent to an IQ score and in the general population, a score of 100 is average. In the 11p15 group, the average GCA score was 99, with scores ranging from 62 (below average) to 140 (above average). This distribution of scores is typical of the general population, indicating that learning is not affected in individuals with SRS 11p15. In the mUPD7 group, the average GCA score was 80, with scores ranging from 57 (below average) to 91 (average). The average score for this group is lower than the general population and the majority of participants had scores in the borderline range. This means that although they do not have intellectual disability, their scores tended to be slightly below average. This indicates that individuals with mUPD7 may have more difficulty with learning than their peers and that additional support in school may be beneficial. Once again, this should be considered on an individual basis. In both groups, there was no evidence of consistent strengths and difficulties between individuals, in relation to the cognitive abilities that were assessed. 

Conclusions

In summary, the findings from this study indicate that some individuals with SRS have difficulty with autistic traits and these tend to be more common in individuals with SRS mUPD7. It is important for families and clinicians to be aware of this increased likelihood of ASD as, in some cases, a full assessment for ASD may be appropriate. In addition, individuals with SRS mUPD7 may be more likely to have difficulty with learning, compared to their peers so it is important to consider whether additional support with learning and development may be useful. It is important to note that there was variability within each group, indicating that some individuals may have more difficulty with autistic traits or learning than others. Therefore, a referral for additional support or services may be beneficial for some individuals with SRS but not required for others.