The ability to perceive approximate numerosity is present in many animal species, and emerges early in human infants. Later in life, it is moderately heritable and associated with mathematical abilities, but the etiology of the Approximate Number System (ANS) and its degree of independence from other cognitive abilities in infancy is unknown.…

Communication deficits have a substantial impact on quality of life for individuals with Angelman syndrome (AS) and their families, but limited qualitative work exists to support the necessary content of measures aiming to assess communication for these individuals. Following best practices for concept elicitation studies, we conducted individual…

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 language learning, aided language modeling refers to the method by which communication partners provide models of the communication system used by individuals with complex communication repertoires that involving both symbols and speech. Providing aided language models creates opportunities for individuals with complex communication repertoires…

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…

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…

Behavioral inflexibility (BI) has been highlighted to occur across genetic and neurodevelopmental disorders. This study characterized BI in two common neurogenetic conditions: Fragile X syndrome (FXS) and Down syndrome (DS). Caregivers of children with FXS (N = 56; with ASD = 28; FXS only = 28) and DS (N = 146) completed the Behavioral…

Purpose: The extant literature suggests that individual differences in speech perception can be linked to broad receptive language phenotype. For example, a recent study found that individuals with a smaller receptive vocabulary showed diminished lexically guided perceptual learning compared to individuals with a larger receptive vocabulary. Here,…

Purpose: Multiple factors impact reading acquisition in individuals with reading disability, including genetic disorders such as Williams syndrome (WS). Despite a relative strength in oral language, individuals with WS usually have an intellectual disability and tend to display deficits in areas associated with reading. There is substantial…

Prader-Willi syndrome (PWS), most recognized for the hallmark hyperphagia and food preoccupations, is caused by the absence of expression of the paternally active genes in the q11-13 region of chromosome 15. Since the recognition of PWS as a genetic disorder, most research has focused primarily on the medical, genetic, and behavioral aspects of…

Purpose: The aim of this study was to investigate language growth in individuals with fragile X syndrome (FXS) from early childhood to adolescence and the influence of maternal responsivity on language growth. Method: We conducted a longitudinal analysis of language development in 55 youths (44 males, 11 females) with FXS. Data collection spanned…

Rett Syndrome (RTT) is characterized by severe impairment in fine motor (FM) and expressive language (EL) function, making accurate evaluations of development difficult with standardized assessments. In this study, the administration and scoring of the Mullen Scales of Early Learning (MSEL) were adapted to eliminate the confounding effects of FM…

Background: This study aimed to compare developmental courses of structural and pragmatic language skills in school-aged children with Williams syndrome (WS) and children with idiopathic intellectual disability (IID). Comparison of these language trajectories could highlight syndrome-specific developmental features. Method: Twelve monolingual…

Background: Individuals with Williams syndrome (WS) show a disharmonic linguistic profile with a clear pattern of strengths and weaknesses. Despite their sociable nature, atypical socio-communicative abilities and deficits in communication and relationship with others have been found. Aim: The aim of the present study was to investigate whether…

Purpose: Researchers have previously shown that individual differences in measures of receptive language ability at age 12 are highly heritable. In the current study, the authors attempted to identify some of the genes responsible for the heritability of receptive language ability using a "genome-wide association" approach. Method: The…