Repetitive behavior in Rubinstein-Taybi syndrome: parallels with autism spectrum phenomenology.

Syndrome specific repetitive behavior profiles have been described previously. A detailed profile is absent for Rubinstein-Taybi syndrome (RTS). The Repetitive Behaviour Questionnaire and Social Communication Questionnaire were completed for children and adults with RTS (N = 87), Fragile-X (N = 196) and Down (N = 132) syndromes, and individuals reaching cut-off for autism spectrum disorder (N = 228). Total and matched group analyses were conducted. A phenotypic profile of repetitive behavior was found in RTS. The majority of behaviors in RTS were not associated with social-communication deficits or degree of disability. Repetitive behavior should be studied at a fine-grained level. A dissociation of the triad of impairments might be evident in RTS.

Delineation of behavioral phenotypes in genetic syndromes: characteristics of autism spectrum disorder, affect and hyperactivity.

We investigated autism spectrum disorder (ASD) symptomatology, hyperactivity and affect in seven genetic syndromes; Angelman (AS; n = 104), Cri du Chat (CdCS; 58), Cornelia de Lange (CdLS; 101), Fragile X (FXS; 191), Prader-Willi (PWS; 189), Smith-Magenis (SMS; 42) and Lowe (LS; 56) syndromes (age range 4-51). ASD symptomatology was heightened in CdLS and FXS. High levels of impulsivity were seen in SMS, AS, CdCS, FXS and adults with CdLS. Negative affect was prominent in adults with CdLS, while positive affect was prominent in adults with AS and FXS. Heightened levels of overactivity and impulsivity were identified in FXS, AS and SMS while low levels were identified in PWS. These findings confirm and extend previously reported behavioral phenotypes.

The prevalence and phenomenology of repetitive behavior in genetic syndromes.

We investigated the prevalence and phenomenology of repetitive behavior in genetic syndromes to detail profiles of behavior. The Repetitive Behaviour Questionnaire (RBQ) provides fine-grained identification of repetitive behaviors. The RBQ was employed to examine repetitive behavior in Angelman (N = 104), Cornelia de Lange (N = 101), Cri-du-Chat (N = 58), Fragile X (N = 191), Prader-Willi (N = 189), Lowe (N = 56) and Smith-Magenis (N = 42) syndromes and individuals with intellectual disability of heterogeneous aetiology (N = 56). Repetitive behavior was variable across syndromes. Fragile X syndrome scored highly on all subscales. Angelman syndrome demonstrated a significantly lowered probability for most behaviors. Prader-Willi, Cri-du-Chat and Smith-Magenis syndrome evidenced unique profiles of repetitive behavior. There is extreme heterogeneity of repetitive behavior across genetic syndromes, highlighting syndrome specific profiles.

Prevalence of autism spectrum phenomenology in Cornelia de Lange and Cri du Chat syndromes.

Autism spectrum disorder characteristics have not been evaluated in Cornelia de Lange and Cri du Chat syndromes using robust assessments. The Autism Diagnostic Observation Schedule and Social Communication Questionnaire were administered to 34 participants with Cornelia de Lange syndrome and a comparison group of 23 participants with Cri du Chat syndrome (M ages 12.4 [SD = 3.8] and 10.3 years [SD = 3.6], respectively). Twenty-one participants with Cornelia de Lange syndrome (61.8%) scored above the autism cut-off on the Autism Diagnostic Observation Schedule compared to 9 with Cri du Chat syndrome (39.2%). Prevalence of autism spectrum disorder characteristics is heightened in Cornelia de Lange syndrome. The profile of characteristics is atypical to that of idiopathic autism.

Genomic imprinting and the expression of affect in Angelman syndrome: what's in the smile?

BACKGROUND: Kinship theory (or the genomic conflict hypothesis) proposes that the phenotypic effects of genomic imprinting arise from conflict between paternally and maternally inherited alleles. A prediction arising for social behaviour from this theory is that imbalance in this conflict resulting from a deletion of a maternally imprinted gene, as in Angelman syndrome (AS), will result in a behavioural phenotype that should evidence behaviours that increase access to maternally provided social resources (adult contact). METHOD: Observation of the social behaviour of children with AS (n = 13), caused by a deletion at 15q11-q13, and a matched comparison group (n = 10) was undertaken for four hours in a socially competitive setting and the effect of adult attention on child behaviours and the effect of child smiling on adult behaviours evaluated using group comparisons and observational lag sequential analyses. RESULTS: The AS group smiled more than the comparison group in all settings, which had different levels of adult attention, and more when the level of adult attention was high. Smiling by children with AS evoked higher levels of adult attention, eye contact and smiling both than by chance and in comparison to other children and this effect was sustained for 30 s to 50 s. Smiling by children with AS was frequently preceded by child initiated contact toward the adult. DISCUSSION: The results are consistent with a kinship theory explanation of the function of heightened levels of sociability and smiling in Angelman syndrome and provide support for an emotion signalling interpretation of the mechanism by which smiling accesses social resources. Further research on other behaviours characteristic of Angelman and Prader-Willi syndromes warrant examination from this perspective.