This study investigated behavioral indicators of social fear in preschool boys with fragile X syndrome (FXS) with a low degree of autism spectrum disorder (ASD) symptoms (FXS-Low; n = 29), FXS with elevated ASD symptoms (FXS-High; n = 25), idiopathic ASD (iASD; n = 11), and typical development (TD; n = 36). Gaze avoidance, escape behaviors, and…

The predictive ability of early consonant inventory and intentional communication on later expressive language was examined in 36 boys with fragile X syndrome (FXS). Autism symptom severity was included as a potential moderator. Participants were visited in their homes twice over a 6-year period, and mother-child interactions were videotaped,…

This brief report examines the implementation of dietary intervention utilizing the specific carbohydrate diet (SCD) for the management of gastrointestinal issues in a 4 year old boy diagnosed with Autism Spectrum Disorder (ASD) and Fragile X Syndrome (FXS). Data relating to anthropometrics, dietary intake, blood markers, gastrointestinal (GI)…

We tested whether empathy is impaired and associated with anxiety in girls with fragile X syndrome (FXS). We measured parent-reported empathy and self-reported anxiety in young girls with FXS and in a developmentally-matched comparison group. Girls with FXS received higher parent-reported scores on cognitive and affective empathy but also…

Many males with FXS meet criteria for ASD. This study was designed to (1) describe ASD symptoms in adolescent and young adult males with FXS (n = 44) and (2) evaluate the contributions to ASD severity of cognitive, language, and psychiatric factors, as well as FMRP (the protein deficient in FXS). A few ASD symptoms on the ADOS-2 were universal in…

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…

Fragile X syndrome (FXS) is the most common known genetic cause of autism spectrum disorder (ASD). Although 50-75% of children with FXS meet ASD criteria, no studies have compared ASD symptoms in infants with FXS versus other high risk groups, such as siblings of children with ASD (ASIBs). Using the Autism Observation Scale for Infants, our…

Grounded in the biopsychosocial models of expressive language in autism spectrum disorder (ASD) and fragile X syndrome (FXS), this dissertation included two novel studies that examined the role of biological (i.e., physiology), psychological (i.e., autistic traits, anxiety symptoms, and child affect) and social (i.e., communication partner…

Recent insight into the underlying molecular and cellular mechanisms of fragile X syndrome (FXS) has led to the proposal and development of new pharmaceutical treatment strategies, and the initiation of clinical trials aimed at correcting core symptoms of the developmental disorder. Consequently, there is an urgent and critical need for outcome…

We used survey methodology to assess parent-reported autism symptomology in 758 individuals (639 males; 119 females) with fragile X syndrome (FXS). Caregivers reported whether their child with FXS had been diagnosed with an autism spectrum disorder (ASD) and endorsed symptoms based on a list of observable behaviors related to ASD diagnoses.…

The Fragile X syndrome (FXS) is the most frequent form of inherited mental disability and is considered a monogenic cause of autism spectrum disorder. FXS is caused by a triplet expansion that inhibits the expression of the "FMR1" gene. The gene product, the Fragile X Mental Retardation Protein (FMRP), regulates mRNA metabolism in brain…

Children with fragile X syndrome (FXS) face high risk for anxiety disorders, yet no studies have explored FXS as a high-risk sample for investigating early manifestations of anxiety outcomes. Negative affect is one of the most salient predictors of problem behaviors and has been associated with both anxiety and autistic outcomes in clinical and…

Purpose: Cluttering is a fluency disorder that has been noted clinically in individuals with fragile X syndrome (FXS). Yet, cluttering has not been systematically characterized in this population, hindering identification and intervention efforts. This study examined the rates of cluttering in male young adults with FXS using expert clinical…

This study characterized the rates of attention-deficit/hyperactivity disorder (ADHD) in adolescent and young adult males with fragile X syndrome (FXS) using a multi-method approach integrating a DSM-based parent interview (Children's Interview for Psychiatric Syndromes; P-ChIPS, Fristad et al., 1998) and a parent rating scale (Child Behavior…

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…