Purpose: Expressive language impairments are common among school-age boys with fragile X syndrome (FXS) and autistic boys. Given the high cooccurrence of autism spectrum disorder (ASD) among individuals with FXS, cross-condition comparisons can elucidate the specificity of such impairments as they relate to ASD. Language samples can provide…

Purpose: Autistic boys and boys with co-occurring fragile X syndrome and autism spectrum disorder (FXS + ASD) demonstrate similar pragmatic language difficulties. The Pragmatic Rating Scale--School Age (PRS-SA) captures ecologically valid metrics of pragmatic language impairments in these populations. It is traditionally scored based on the Autism…

Autism spectrum disorder (ASD) and fragile X syndrome (FXS) are neurodevelopmental disorders with overlapping pragmatic language impairments. Prior work suggests pragmatic language differences may run in families. This study examined specific pragmatic difficulties (i.e., linguistic mazes and perseverations) in boys (9-18 years) with idiopathic…

Purpose: The current study addresses a gap in the literature regarding syntactic development of adolescent boys with fragile X syndrome (FXS) and Down syndrome (DS). Specifically, we ask whether syntactic skills plateau or continue to change during adolescence for these groups and whether the profile of syntactic change differs between boys with…

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 =…

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…

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…

We explored sensory features as distinguishing characteristics of Autism spectrum disorder (ASD). Four groups of males (n = 36): Six with 47, XYY syndrome and ASD (XYY+ASD), six with 47, XYY syndrome and no ASD (XYY-ASD), 12 with idiopathic ASD (ASD-I) and 12 typically developing (TYP). The short sensory profile (SSP) the sensory challenge…

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…

Klinefelter syndrome (47,XXY) is associated with problems in social interaction and behavioral adaptation. Sixteen adolescents and adult men with 47,XXY enrolled in a pilot-study evaluating the effectiveness of Social Management Training (SMT), a novel neurocognitive-behavioral treatment program targeted at improving social, emotional, and…

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)…

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: Chromosome 16p11.2 deletion syndrome (OMIM #611913) is a rare genetic condition resulting from the partial deletion of approximately 35 genes located at Chromosome 16. Affected people exhibit a variable clinical profile, featuring mild dysmorphisms, motor problems, developmental delay, mild intellectual disability (ID), socialization…

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…