Autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) are highly heritable neurodevelopmental disorders that frequently co-occur. Both rare and common genetic variants are important for ASD and ADHD risk but their combined contribution to clinical heterogeneity is unclear. In a sample of 39 ASD and/or ADHD families we…

Self-injurious behaviors (SIB) are elevated in autism spectrum disorder (ASD) and related genetic disorders, but the genetic and biological mechanisms that contribute to SIB in ASD are poorly understood. This study examined rates and predictors of SIB in 112 individuals with disruptive mutations to ASD-risk genes. Current SIB were reported in 30%…

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…

Smith-Magenis syndrome (SMS) is a genetic syndrome most often caused by a deletion on chromosome 17 or more rarely by a mutation in the retinoic acid-induced 1 gene. The aim of this study was to investigate the Developmental Behavior Checklist (DBC) profile of persons with SMS and the associations between behavioural and emotional problems, age,…

Parents of toddlers with an older sibling with autism spectrum disorder (ASD; high risk, HR) and parents of low risk (LR) toddlers with typically-developing older siblings read a wordless picture book to their child at 22 and 28 months. Parents' and toddlers' internal state language (ISL) was coded; parents reported on toddlers' use of ISL.…

This study examined trajectories of daily living skills, behavior problems, body mass index (BMI), and health conditions spanning nearly a decade in adolescents and adults with fragile X syndrome (N = 134; age range at study end = 19-49 years), examining influences of sex and autism spectrum disorder (ASD) symptoms. Hierarchical linear modeling…

The development of an expressive language score for people with autism based on the ADOS-2 was recently reported by Mazurek et al. (2019). The current study examined the construct validity of the ADOS-2 expressive language score (ELS) in a sample of adolescents with fragile X syndrome (n = 45, 10 girls), a neurodevelopmental disorder with high…

Gold-standard diagnostic assessments of autism spectrum disorder (ASD) symptomatology were conducted on 63 children (mean CA: 8.81 years) with 7q11.23 duplication syndrome, one of the copy number variants identified by Sanders et al. ("Neuron" 70:863-885, 2011a) as associated with ASD. ASD classification rate was 39.6% for the Autism…

Background: The present study aimed at investigating mother-child dyadic co-regulation patterns in dyads with children with intellectual disability (ID). Method: 24 children paired for developmental age and vocabulary size (8 with chromosome 14 aberrations, 8 with Down syndrome, and 8 with typical development) and their mothers participated in the…

Friendships and social participation are key domains of quality of life for individuals with intellectual disabilities. This study examined the friendships, social and recreational activities, and family social networks of individuals with intellectual disabilities from two distinct diagnostic groups: individuals diagnosed with fragile X syndrome…

Age-related behavioural change in Cornelia de Lange syndrome is poorly understood. We report a 7 year follow-up study of adaptive behaviour, autism spectrum disorder symptomatology, language skills and behavioural characteristics in 30 individuals with Cornelia de Lange syndrome, compared with 18 individuals with Cri du Chat syndrome. The…

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…

Sotos syndrome is a congenital overgrowth disorder with an incidence of approximately 1 in 14,000. This study investigated behavioural characteristics of ASD within a large cohort of individuals with Sotos syndrome (n = 78). As measured by the Social Responsiveness Scale, second edition (SRS-2), 65 participants (83.33%) met clinical cut-off…

Purpose: This study examined use of a speaker's direction of gaze during word learning by boys with fragile X syndrome (FXS), boys with nonsyndromic autism spectrum disorder (ASD), and typically developing (TD) boys. Method: A fast-mapping task with follow-in and discrepant labeling conditions was administered. We expected that the use of speaker…

A cross-sectional analysis was used to examine age-related differences in ASD symptoms and corresponding differences in disruptive behavior and social skills in 281 adult men with fragile X syndrome. Four age groups were created: 18-21, 22-29, 30-39, and 40-49 years. The 18-21 year-old group was reported to have more impairments in verbal…