Background: Recent advances in genetics are particularly relevant in the field of intellectual disability (ID), where sub-microscopic deletions or duplications of genetic material are increasingly implicated as known or suspected causal factors. Data-driven reports on the impact of providing an aetiological explanation in ID are needed to help…

Background: A number of genetic conditions with associated intellectual disability and/or special educational needs have increasingly well-defined behavioural phenotypes. Thus, the concept of "behavioural phenotype" and aetiology of intellectual disability may be important with regard to school-based interventions. Method: The evidence for…

Background: Studies conducted on mild intellectual disability (MID) in children are infrequent and the prevalence rates vary widely. This study aimed to estimate the prevalence of MID in children in a French county (Isère), to describe the clinical signs and associated comorbidities, and to specify the aetiologies of this disability. Methods: The…

Background: Genetically Williams syndrome (WS) promises to provide essential insight into the pathophysiology of cortical development because its ~28 deleted genes are crucial for cortical neuronal migration and maturation. Phenotypically, WS is one of the most puzzling childhood neurodevelopmental disorders affecting most intellectual…

Background: Chromosome 22q11.2 microdeletion syndrome (22q11.2DS) is a genetic syndrome characterised by a unique cognitive profile. Individuals with the syndrome present several non-verbal deficits, including visual memory impairments and atypical exploration of visual information. In this study, we seek to understand how visual attention may…

Background: Williams syndrome (WMS) is a rare genetic disorder with an estimated prevalence of 1 in 20,000 live births. Among other characteristics, WMS has a distinctive cognitive profile with spared face processing and language skills that contrasts with impairment in the cognitive domains of spatial cognition, problem solving and planning. It…

Background: Self-injurious and aggressive behaviours are reported as components of some behavioural phenotypes but there are few studies comparing across syndrome groups. In this study we examined the prevalence of these behaviours and the associated person characteristics in seven genetic syndromes. Methods: Questionnaire data on self-injury and…

Background: 22q11.2 deletion syndrome (22q11DS) is the second most prevalent genetic syndrome and has a characteristic academic and behavioural phenotype. The primary objective of the current study was to examine the childhood predictors of written expression achievement in adolescents with 22q11DS. Written expression is an important skill that…

Background: Self-injurious behaviour (SIB) is a devastating problem observed in individuals with various neurodevelopmental disorders, including specific genetic syndromes as well as idiopathic intellectual and developmental disability. Although an increased prevalence of SIB has been documented in specific genetic mutations, little is known about…

Background: Genetic disorders occasionally provide the means to uncover potential mechanisms linking gene expression and physical or cognitive characteristics or behaviour. Prader-Willi syndrome (PWS) is one such genetic disorder in which differences between the two main genetic subtypes have been documented (e.g. higher verbal IQ in one vs.…

Background: Numerous studies have assessed the socio-cognitive profile in Williams syndrome (WS) and, independently, in 22q11.2 deletion syndrome (22q11.2DS). Yet, a cross-syndrome comparison of these abilities between individuals with these two syndromes with known social deficits has not been conducted. Methods: Eighty-two children participated…

Background: The current study focuses on mothers and fathers of children with three rare genetic syndromes that are relatively unexplored in terms of family experience: Angelman syndrome, Cornelia de Lange syndrome and Cri du Chat syndrome. Method: Parents of children with Angelman syndrome (n = 15), Cornelia de Lange syndrome (n = 16) and Cri du…

Background: Behavioural phenotypes associated with genetic syndromes have been extensively investigated in order to generate rich descriptions of phenomenology, determine the degree of specificity of behaviours for a particular syndrome, and examine potential interactions between genetic predispositions for behaviour and environmental influences.…

Background: Children with 22q11.2 deletion syndrome (22q11DS) are at risk for social-behavioural and neurocognitive sequelae throughout development. The current study examined the impact of family environmental characteristics on social-behavioural and cognitive outcomes in this paediatric population. Method: Guardians of children with 22q11DS…

Background: Prader-Willi syndrome (PWS) is characterised by hypotonia, hypogonadism, short stature, obesity, behavioural problems, intellectual disability, and delay in language, social and motor development. There is very limited knowledge about visual-motor integration in children with PWS. Method: Seventy-three children with PWS aged 7-17 years…