Date of Award

Fall 2019

Document Type

Open Access Dissertation



First Advisor

Jane Roberts


This dissertation is comprised of two manuscripts which examine the longitudinal development of autism symptomatology in young children at risk for developing autism spectrum disorder (ASD); individuals with Fragile x syndrome (FXS) and Down syndrome (DS). The first study is a within group analysis of the longitudinal development of ASD symptomatology in young children with FXS, and how diagnostic stability, language and non-verbal cognitive functioning may predict these trajectories. This paper provides insight into ASD diagnostic stability patterns within FXS, and how symptoms change over time across these groups. The second paper will extend this work by presenting a pilot cross-syndrome comparison, which includes young children with FXS, DS and non-syndromic ASD to examine hypothesis of unique ASD symptom trajectories between the disorders. This pilot examination will set the stage for future larger scale cross syndrome comparisons to target these important questions. Together, the findings presented here inform the theoretical understanding of ASD within FXS, as well as support clinical recommendations for screening, monitoring and diagnosing ASD within FXS.


© 2019, Kelly Elizabeth Caravella