Fragile X syndrome (FXS), as a monogenic cause of intellectual disability and autism spectrum disorder, has been one of the first neurodevelopmental disorders in which molecular and neuronal mechanisms of disease have been identified, leading to the concept of targeting the underlying disease to reverse symptoms. Translating findings in basic…

We examined potential phenotypic differences in eye gaze avoidance exhibited by boys with autism spectrum disorder (ASD) and boys with fragile X syndrome (FXS). In Study 1, the Eye Contact Avoidance Scale (ECAS) was administered to caregivers of boys aged 7-18 years with FXS (n = 148), ASD (n = 168), and mixed developmental disabilities (MDD; n =…

Behavioral inflexibility (BI) has been highlighted to occur across genetic and neurodevelopmental disorders. This study characterized BI in two common neurogenetic conditions: Fragile X syndrome (FXS) and Down syndrome (DS). Caregivers of children with FXS (N = 56; with ASD = 28; FXS only = 28) and DS (N = 146) completed the Behavioral…

Early identification of behavioral risk markers for anxiety is essential to optimize long-term outcomes in children with neurodevelopmental disorders. This study analyzed attentional avoidance and its relation to anxiety and autism spectrum disorder (ASD) symptomatology during social and nonsocial fear conditions in toddlers with fragile X…

To date, health related quality of life (QoL) has not been systematically evaluated in youth with fragile X syndrome (FXS), the most common single gene cause of autism and the most common inherited form of developmental disability. We describe QoL data gathered using the Pediatric Quality of Life Inventory (PedsQL) completed online by 364 parents…

We directly assessed the broader aspects of sociability (social enjoyment, social motivation, social interaction skills and social discomfort) in individuals with Cornelia de Lange (CdLS), fragile X (FXS) and Rubinstein-Taybi syndromes (RTS), and their association with autism characteristics and chronological age in these groups. Individuals with…

Limited information is available concerning the specificity of the forms and functions of aggressive behavior exhibited by boys with fragile X syndrome (FXS). To investigate these relationships, we conducted indirect functional assessments of aggressive behavior exhibited by 41 adolescent boys with FXS and 59 age and symptom-matched controls with…

Anxiety disorders affect ~ 15-20% of youths without neurodevelopmental disorders, with persons having autism spectrum disorder (ASD) and fragile X syndrome (FXS) at elevated risk for anxiety disorders. Few studies have compared rates and predictors of anxiety disorders in adolescents with FXS or ASD. This study directly compares rates, predictors,…

Telehealth is increasingly being employed to extend the reach of behavior analytic interventions to families of children with developmental disorders who exhibit problem behaviors. In this preliminary study, we examined whether function-based behavior analytic interventions could be delivered via telehealth over 12 weeks to decrease problem…

Background: Individuals with intellectual and developmental disabilities are more likely to engage in problem behaviours than peers with typical development. The purpose of this study was to provide descriptive and qualitative information about problem behaviours in children with fragile X syndrome (FXS) and how families respond to these…

Identifying the early signs of developmental disability is important for ensuring timely diagnosis and early intervention. Day-care workers may be in a prime position to notice potential developmental deviations, but it is unclear if they can accurately recognize subtle early signs of atypical development. Sixty day-care workers examined…

Cognitive and behavioral correlates of molecular variations related to the FMR1 gene have been studied rather extensively, but research about the long-term outcome in individuals with fragile X spectrum disorders remains sparse. In this review, we present an overview of aging research and recent findings in regard to cellular and clinical…

This comprehensive, interdisciplinary handbook presents the latest research in the study, assessment, treatment, and understanding of intellectual and developmental disabilities. The past five decades have resulted in dramatic breakthroughs in the understanding of intellectual and developmental disabilities (IDD). Editor-in-Chief Laraine Masters…

Purpose: This study compared and characterized the tense and agreement productivity of boys with fragile X syndrome (FXS), children with developmental language disorder (DLD), and children with typical development (TD) matched on mean length of utterance. Method: Twenty-two boys with FXS (M[subscript age] = 12.22 years), 19 children with DLD…

Background: Retrospective parental reports have often been used to identify the early characteristics of children later diagnosed with a developmental disorder. Method: We applied this methodology to document 13 parents' initial concerns about the development of their 17 children later diagnosed with fragile X syndrome (FXS). Parents were…