Towards an early differential diagnosis in autism spectrum disorders and fragile X syndrome. A systematic review

Introduction. Nearly 60% of those diagnosed with fragile X syndrome show comorbidity with autism. Thus, there are similarities and differences between both conditions that lead to very different clinical manifestations. However, an early differential diagnosis may help professionals to detect deficits and enhance strengths to apply the best suitable intervention. The purpose of this scoping review was to provide a comprehensive overview of the relation and the differences between autism and fragile X syndrome to orientate diagnosis and intervention. Materials and methods. The research for articles was carried out in PsycInfo, Medline, SCOPUS and Web of Science, including scientific articles published from 2010 to 2020 and children aged 0-6 years. The scoping review followed the PRISMA-ScR criteria. Results. 22 studies were selected. Results were reviewed in terms of structural and morphological changes and cognitive, communicative, social-emotional and sensory-motor skills. Conclusions. Different growing cerebral patterns are observed in both conditions. Besides, there are early signs from the different developmental areas studied that show comorbidity or allow early differentiation. However, attentional function or repetitive mannerisms, among others, need further research.