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…

Truncating variants of the "MAGEL2" gene, one of the protein-coding genes within the Prader-Willi syndrome (PWS) critical region on chromosome 15q11, cause Schaaf-Yang syndrome (SYS)--a neurodevelopmental disorder that shares several clinical features with PWS. The current study sought to characterize the neurobehavioral phenotype of SYS…

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…

Purpose: The ability to repair breakdowns in communication is an important pragmatic language skill that helps to maintain clear and meaningful interactions. Examining this ability in genetically based neurodevelopmental disabilities in which pragmatics are affected can provide important information about the precise pragmatic skills impacted…

Verbal--spatial discrepancies are common in healthy individuals and in those with neurodevelopmental disorders associated with cognitive control deficits including: Autism Spectrum Disorder, Non-Verbal Learning Disability, Fragile X, 22q11 deletion, and Turner Syndrome. Previous data from healthy individuals suggest that the magnitude of the…

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…

15q13.3 microdeletion syndrome causes a spectrum of cognitive disorders, including intellectual disability and autism. We aimed to determine if any or all of three cognitive testing systems (the KiTAP, CogState, and Stanford-Binet) are suitable for assessment of cognitive function in affected individuals. These three tests were administered to ten…

The prevalence of autism spectrum disorder (ASD) in many genetic disorders is well documented but not as yet in Mucopolysaccharidosis type III (MPS III). MPS III is a recessively inherited metabolic disorder and evidence suggests that symptoms of ASD present in MPS III. This systematic review examined the extant literature on the symptoms of ASD…

The next several pages are intended as a "Commentary" on the six target articles bundled together as a Special Issue of the "Journal of Cognition and Development"--literature reviews and research reports all intended to "build bridges" between the study of cognitive development in typical and atypical populations.

Each year, the Interagency Autism Coordinating Committee (IACC) releases a list of scientific advances that represent significant progress in the field. The "2019 IACC Summary of Advances" provides short, plain language summaries of the top research breakthroughs selected by the IACC from a pool of research articles nominated by the…

Background: Prior research suggests that 60-74% of males and 16-45% of females with fragile X syndrome (FXS) meet criteria for autism spectrum disorder (ASD) in research settings. However, relatively little is known about the rates of clinical diagnoses in FXS and whether such diagnoses are consistent with those performed in a research setting…

Objective: There is clinical heterogeneity among the autism spectrum disorders (ASD). The presence of dysmorphology (minor physical anomalies; MPAs) is one possible tool for defining a clinically relevant subset in ASD. This study employs an adaptation of Miles and Hillman's (2000) classifications by using photographs to identify a subgroup with…

Fragile X syndrome is the leading inherited cause of intellectual disability. Most boys with fragile X syndrome have impaired cognition and language deficits, with significant within-syndrome variability. Syntax may be especially delayed relative to nonverbal cognition; however, little is known about the specificity of delay, the sources of that…

The primary objective of this study was to study the impact of ASD/ADHD on general intellectual ability and profile, executive functions and visuo-motor skills in children and adults with 22q11 deletion syndrome (22q11DS). A secondary aim was to study if gender, age, heart disease, ASD, ADHD or ASD in combination with ADHD had an impact on general…