Autistic traits and cognitive abilities associated with two molecular causes of Silver-Russell syndrome

Silver-Russell syndrome is a rare genetic imprinting disorder. Two molecular causes of Silver-Russell syndrome have been identified: loss of methylation on chromosome 11p15 (11p15 LOM) and maternal uniparental disomy for chromosome 7 (matUPD7). Current understanding of the cognitive and behavioural phenotypes associated with these two molecular subtypes is limited. This study aimed to address this gap in the literature. The Social Responsiveness Scale (SRS-2), was used to assess autistic traits in individuals with 11p15 LOM (n = 47) and matUPD7 (n = 32). A subset of participants with 11p15 LOM (n = 18) and matUPD7 (n = 15) completed in-person assessments: the Autism Diagnostic Observation Schedule (ADOS-2) and the British Ability Scales (BAS3). Overall, 37.50% of the matUPD7 group and 10.64% of the 11p15 LOM group scored above the SRS-2 severe clinical cut-off. Based on the ADOS-2, 33.33% of the matUPD7 participants and 11.11% of the 11p15 LOM participants scored above cut-off for autism spectrum/autism. Intellectual ability was significantly lower in the matUPD7 group (mean = 79.86), compared to the 11p15 LOM group (mean = 98.56). However, there was no evidence of an uneven cognitive profile associated with either group or of an association between autistic traits and intellectual ability. Although both 11p15 LOM and matUPD7 have the same clinical diagnosis of Silver-Russell syndrome, there are some differences in the cognitive and behavioural phenotypes between these two molecular subtypes. This has implications for considering access to services, intervention and support within these populations, particularly in relation to learning and behaviour.