Short report: Autistic symptoms in Sotos syndrome, preliminary results from a case-control study.

Background: An extremely heterogeneous neuropsychological phenotype has been reported in Sotos Syndrome (SoS), including socio-communicative and behavioral difficulties referred to Autism Spectrum Disorder (ASD). Nonetheless, to date, only few data are available on the topic.

Aim: To investigate ASD symptoms within a sample of children with SoS in comparison to a matched control group of individuals with idiopathic ASD.

Methods: A convenience sample of SoS (n = 33, age: 9.8 ± 4.1) and ASD (n = 33, age: 9.9 ± 4.1), was included. Autistic symptoms' assessment was performed through the administration of the Autism Diagnostic Observation Schedule-Second Edition- ADOS-2, the Social Responsiveness Scale -SRS and the Social Communication Questionnaire-SCQ.

Results: 72.7% of SoS children presented mild to moderate levels of ASD symptoms as measured by the ADOS-2. Oneway ANOVA analysis showed that SoS individuals presenting lower IQ demonstrated higher ASD symptom's level (p = 0.01). No statistically significant differences emerged between the SoS and ASD groups within the SRS total score domain (p = 0.95).

Conclusions And Implications: Our results support the evidence for an increased risk for ASD in SoS, suggesting that the ASD symptoms' assessment should be regularly performed in SoS children, with subsequent important implications in terms of therapeutic strategies and later outcome.