Williams syndrome

Williams syndrome

Williams syndrome (WS) is a relatively rare microdeletion disorder that occurs in as many as 1:7,500 individuals. WS arises due to the mispairing of low-copy DNA repetitive elements at meiosis. The deletion size is similar across most individuals with WS and leads to the loss of one copy of 25-27 genes on chromosome 7q11.23. The resulting unique disorder affects multiple systems, with cardinal features including but not limited to cardiovascular disease (characteristically stenosis of the great arteries and most notably supravalvar aortic stenosis), a distinctive craniofacial appearance, and a specific cognitive and behavioural profile that includes intellectual disability and hypersociability. Genotype-phenotype evidence is strongest for ELN, the gene encoding elastin, which is responsible for the vascular and connective tissue features of WS, and for the transcription factor genes GTF2I and GTF2IRD1, which are known to affect intellectual ability, social functioning and anxiety. Mounting evidence also ascribes phenotypic consequences to the deletion of BAZ1B, LIMK1, STX1A and MLXIPL, but more work is needed to understand the mechanism by which these deletions contribute to clinical outcomes. The age of diagnosis has fallen in regions of the world where technological advances, such as chromosomal microarray, enable clinicians to make the diagnosis of WS without formally suspecting it, allowing earlier intervention by medical and developmental specialists. Phenotypic variability is considerable for all cardinal features of WS but the specific sources of this variability remain unknown. Further investigation to identify the factors responsible for these differences may lead to mechanism-based rather than symptom-based therapies and should therefore be a high research priority.

Williams Syndrome Associated With Autism Spectrum Disorder: A Case Report and Review of the Literature

We present a case report of patient H., a four-year-old male who was brought to the neurogenetics clinic of a university hospital. He was diagnosed with Williams syndrome (WS), which was confirmed by microarray; the patient was also diagnosed with autism spectrum disorder (ASD) by the pediatric neurology department. It is known that due to WS's phenotypical pattern, a co-diagnosis of both ASD and WS is apparently unlikely and often ignored. This case report discusses how this matter is addressed in the literature to understand the overlap of these two diseases, treating this case as a study model.

Functional basic reading skills in Williams syndrome

This study investigated whether individuals with Williams syndrome (WS) can attain a functional level of basic reading skills. The Study also investigated broader cognitive factors associated with reading ability in individuals with WS. Thirty individuals with WS participated in this study (mean chronological age 21 years and mean mental age 7 years 7 months). The results supported our hypotheses that: firstly, reading abilities would be heterogeneous in WS; secondly, at least some WS individuals are capable of achieving a functional basic reading level; and thirdly, on average, WS individuals would find reading of nonwords more difficult than reading of regular and irregular words. Moreover, higher reading ability was found to be associated with increased outcomes in adaptive functioning, in particular, Written and Expressive Communication skills and Community Living skills, highlighting the potential benefits of developing reading abilities in WS. Although Intelligence Quotient (IQ) was related to overall basic reading ability generally, it was not found to be a determining factor in reading subtypes. Several cognitive skills known to be related to reading ability in typically developing individuals were found to be associated with reading performance and reading subtypes. Implications for appropriate reading instruction are discussed.

Attention Bias to Emotional Faces Varies by IQ and Anxiety in Williams Syndrome

Individuals with Williams syndrome (WS) often experience significant anxiety. A promising approach to anxiety intervention has emerged from cognitive studies of attention bias to threat. To investigate the utility of this intervention in WS, this study examined attention bias to happy and angry faces in individuals with WS (N = 46). Results showed a significant difference in attention bias patterns as a function of IQ and anxiety. Individuals with higher IQ or higher anxiety showed a significant bias toward angry, but not happy faces, whereas individuals with lower IQ or lower anxiety showed the opposite pattern. These results suggest that attention bias interventions to modify a threat bias may be most effectively targeted to anxious individuals with WS with relatively high IQ.

Adaptive functioning in Williams syndrome and its relation to demographic variables and family environment

This study assessed adaptive functioning in children and adults with Williams syndrome. The aims were to: (1) profile adaptive functioning; (2) investigate the relationship between adaptive functions and gender, CA, and IQ; (3) investigate the relationship between levels of adaptive functioning and family environment characteristics. In line with predictions: (1) there was extensive variability in adaptive functions; (2) neither gender nor IQ were significantly related to adaptive skills, but Communication skills and Interpersonal Relationship skills failed to make appropriate gains relative to same aged peers and (3) adaptive functioning was significantly related to family environment. Practical and clinical implications are discussed.

Developmental changes in mental rotation ability and visual perspective-taking in children and adults with Williams syndrome

Williams syndrome (WS) is a genetic disorder caused by the partial deletion of chromosome 7. Individuals with WS have atypical cognitive abilities, such as hypersociability and compromised visuospatial cognition, although the mechanisms underlying these deficits, as well as the relationship between them, remain unclear. Here, we assessed performance in mental rotation (MR) and level 2 visual perspective taking (VPT2) tasks in individuals with and without WS. Individuals with WS obtained lower scores in the VPT2 task than in the MR task. These individuals also performed poorly on both the MR and VPT2 tasks compared with members of a control group. For the individuals in the control group, performance scores improved during development for both tasks, while the scores of those in the WS group improved only in the MR task, and not the VPT2 task. Therefore, we conducted a second experiment to explore the specific cognitive challenges faced by people with WS in the VPT2 task. In addition to asking participants to change their physical location (self-motion), we also asked them to adopt a third-person perspective by imagining that they had moved to a specified location (self-motion imagery). This enabled us to assess their ability to simulate the movement of their own bodies. The performance in the control group improved in both the self-motion and self-motion imagery tasks and both performances were correlated with verbal mental age. However, we did not find any developmental changes in performance for either task in the WS group. Performance scores for the self-motion imagery task in the WS group were low, similar to the scores observed for the VPT2 in this population. These results suggest that MR and VPT2 tasks involve different processes, and that these processes develop differently in people with WS. Moreover, difficulty completing VPT2 tasks may be partly because of an inability of people with WS to accurately simulate mental body motion.

Toddlers with Williams syndrome process upright but not inverted faces holistically

Holistic processing of upright, but not inverted, faces is a marker of perceptual expertise for faces. This pattern is shown by typically developing individuals beginning at age 7 months. Williams syndrome (WS) is a rare neurogenetic developmental disorder characterized by extreme interest in faces from a very young age. Research on the effects of inversion on holistic processing of faces by older children and adults with WS has produced mixed results. Younger children with WS were not included in these previous studies. Using the habituation switch paradigm, we demonstrated that 15-35-month-olds with WS process upright, but not inverted, faces holistically. This study provides evidence of perceptual expertise for faces in individuals with WS early in life.

Sensitivity of the autonomic nervous system to visual and auditory affect across social and non-social domains in williams syndrome

Although individuals with Williams syndrome (WS) typically demonstrate an increased appetitive social drive, their social profile is characterized by dissociations, including socially fearless behavior coupled with anxiousness, and distinct patterns of "peaks and valleys" of ability. The aim of this study was to compare the processing of social and non-social visually and aurally presented affective stimuli, at the levels of behavior and autonomic nervous system (ANS) responsivity, in individuals with WS contrasted with a typically developing (TD) group, with the view of elucidating the highly sociable and emotionally sensitive predisposition noted in WS. Behavioral findings supported previous studies of enhanced competence in processing social over non-social stimuli by individuals with WS; however, the patterns of ANS functioning underlying the behavioral performance revealed a surprising profile previously undocumented in WS. Specifically, increased heart rate (HR) reactivity, and a failure for electrodermal activity to habituate were found in individuals with WS contrasted with the TD group, predominantly in response to visual social affective stimuli. Within the auditory domain, greater arousal linked to variation in heart beat period was observed in relation to music stimuli in individuals with WS. Taken together, the findings suggest that the pattern of ANS response in WS is more complex than previously noted, with increased arousal to face and music stimuli potentially underpinning the heightened behavioral emotionality to such stimuli. The lack of habituation may underlie the increased affiliation and attraction to faces characterizing individuals with WS. Future research directions are suggested.

Genome-scale study of transcription factor expression in the branching mouse lung

BACKGROUND

Mammalian lung development consists of a series of precisely choreographed events that drive the progression from simple lung buds to the elaborately branched organ that fulfills the vital function of gas exchange. Strict transcriptional control is essential for lung development. Among the large number of transcription factors encoded in the mouse genome, only a small portion of them are known to be expressed and function in the developing lung. Thus a systematic investigation of transcription factors expressed in the lung is warranted.

RESULTS

To enrich for genes that may be responsible for regional growth and patterning, we performed a screen using RNA in situ hybridization to identify genes that show restricted expression patterns in the embryonic lung. We focused on the pseudoglandular stage during which the lung undergoes branching morphogenesis, a cardinal event of lung development. Using a genome-scale probe set that represents over 90% of the transcription factors encoded in the mouse genome, we identified 62 transcription factor genes with localized expression in the epithelium, mesenchyme, or both. Many of these genes have not been previously implicated in lung development.

CONCLUSIONS

Our findings provide new starting points for the elucidation of the transcriptional circuitry that controls lung development.