Broader phenotypes associated with genetic liability, including mild difficulties with pragmatic language skills, have been documented in mothers of children with autism spectrum disorder (ASD) and mothers of children with fragile X syndrome (FXS). This study investigated the relationship between pragmatic difficulties and indicators of maternal…

By adulthood, most males with fragile X syndrome (FXS) require support to navigate day-to-day settings. The present study cross-sectionally: (1) characterized the profile of daily living skills in males with FXS and (2) examined associated participant characteristics (i.e., fragile X mental retardation protein [FMRP] expression, nonverbal…

In the present study, language performance on standardized assessments (e.g., overall verbal performance, receptive and expressive vocabulary) and spontaneous language produced in play was compared between preschool-aged boys with autism spectrum disorder ([subscript n]ASD, n = 25) and boys with fragile X syndrome (FXS, n = 16). At the…

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…

Purpose: This study examined relationships among family characteristics, caregiver change in use of strategies, and child growth in spoken language over the course of a parent-implemented language intervention (PILI) that was developed to address some of the challenges associated with the fragile X syndrome (FXS) phenotype. Method: Participants…

Despite the similarities observed between the fragile X syndrome (FXS) and autism spectrum disorder (ASD) phenotypes, few studies have compared their behavioral profiles outside of ASD symptomatology. In the present study, we sought to compare lexical and grammatical abilities in these two conditions. Comparisons of language abilities in both of…

Purpose: This study used a prospective longitudinal design to evaluate the trajectory and predictors of noncomprehension signaling in male and female youth with fragile X syndrome (FXS). Method: A direction-following task in which some of the directions were inadequate was administered. Participants were 52 youth (36 boys, 16 girls) with FXS. Upon…

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…

Although males with fragile X syndrome (FXS) are frequently described as demonstrating autism symptomatology, there is much debate regarding whether the behavioral symptoms representing the core domains of autism are the result of the same or different underlying neurological/psychological mechanisms. The present study used a cross-sectional…

The present study evaluated the ability of males with fragile X syndrome (FXS), nonsyndromic autism spectrum disorder (ASD), or typical development to learn new words by using as a cue to the intended referent an emotional reaction indicating a successful (excitement) or unsuccessful (disappointment) search for a novel object. Performance for all…

Symptoms of autism are frequent in males with fragile X syndrome (FXS), but it is not clear whether symptom profiles differ from those of nonsyndromic ASD. Using individual item scores from the Autism Diagnostic Inventory-Revised, we examined which current symptoms of autism differed in boys with FXS relative to same-aged boys diagnosed with…