Airflow Obstruction in Adults with Williams Syndrome and Mice with Elastin Insufficiency

Williams−Beuren syndrome (WS) results from the deletion of 25−27 coding genes, including elastin (ELN), on human chromosome 7q11.23. Elastin provides recoil to tissues; emphysema and chronic obstructive pulmonary disease have been linked to its destruction. Consequently, we hypothesized that elastin insufficiency would predispose to obstructive features. Twenty-two adults with WS (aged 18−55) and controls underwent pulmonary function testing, 6 min walk, and chest computed tomography (CT). Lung and airspace dimensions were assessed in Eln+/− and control mice via microCT and histology. The forced expiratory volume in 1 s (FEV1) and the ratio of FEV1 to forced vital capacity (FVC) were lower in adults with WS (p < 0.0001 and p < 0.05, respectively). The FEV1/FVC ratio was more frequently below the lower limit of normal in cases (p < 0.01). The ratio of residual volume to total lung capacity (RV/TLC, percent predicted) was higher in cases (p < 0.01), suggesting air trapping. People with WS showed reduced exercise capacity (p < 0.0001). In Eln+/− mice, ex vivo lung volumes were increased (p < 0.0001), with larger airspaces (p < 0.001). Together these data show that elastin insufficiency impacts lung physiology in the form of increased air trapping and obstruction, suggesting a role for lung function monitoring in adults with WS.

Comparison of Adaptive Functioning in Children with Williams Beuren Syndrome and Autism Spectrum Disorder: A Cross-Syndrome Study

Williams Beuren syndrome (WBS) and autism spectrum disorder (ASD) have been long considered as "polar opposite" disorders. Although children with WBS appears to be hypersociable, recent researches have revealed difficulties in socio-communicative skills such as shared attention, showing or giving objects, social relationships comprehension, pragmatic use of language, and emotion's recognition. The aim of this cross-syndrome study is to compare clinician-report adaptive profiles of two wide developmental range children by means of Vineland Adaptive Behavior Scales-Interview Edition, Survey Form. Eighty individuals, 40 with WBS and 40 with ASD (31 preschoolers and 49 scholars) with ASD and WBS matched for chronological age and developmental/cognitive level were recruited. Analysis of domains and subdomains have been reported. Results showed no significant difference in global adaptive level between WBS and ASD in both preschooler and scholar children. Communication domain significantly differ in preschoolers (higher in WBS children), but not in scholars. Expressive subdomain significantly differ in both preschoolers and scholars (higher in WBS children). Play and Leisure subdomain significantly differ in scholars (higher in WBS children), but not in preschoolers. Our results support hypothesis on a shared global adaptive impairment in children with WBS and ASD, by extending this findings to scholar-age children. Analysis of domains and subdomains differences highlight the need for interventions targeting social-pragmatic skills since first years of life. Differences in preschoolers and scholars adaptive profiles could be explained through a developmental perspective. LAY SUMMARY: Little is known about differences in adaptive profiles between Williams Beuren syndrome and autism spectrum disorder. Our results show similarities in global adaptive level and difference in communication level. Furthermore, expressive skills seem to be higher in Williams Beuren Syndrome. Autism Res 2021, 14: 748-758. © 2020 International Society for Autism Research and Wiley Periodicals LLC.

Molecular investigation, using chromosomal microarray and whole exome sequencing, of six patients affected by Williams Beuren syndrome and Autism Spectrum Disorder

Williams Beuren syndrome (WBS) is a multiple malformations/intellectual disability (ID) syndrome caused by 7q11.23 microdeletion and clinically characterized by a typical neurocognitive profile including excessive talkativeness and social disinhibition, often defined as “overfriendliness” and “hyersociability”. WBS is generally considered as the polar opposite phenotype to Autism Spectrum Disorder (ASD). Surprisingly, the prevalence of ASD has been reported to be significantly higher in WBS (12%) than in general population (1%). Our study aims to investigate the molecular basis of the peculiar association of ASD and WBS. We performed chromosomal microarray analysis and whole exome sequencing in six patients presenting with WBS and ASD, in order to evaluate the possible presence of chromosomal or gene variants considered as pathogenic.

Our study shows that the presence of ASD in the recruited WBS patients is due to i) neither atypically large deletions; ii) nor the presence of pathogenic variants in genes localized in the non-deleted 7q11.23 allele which would unmask recessive conditions; iii) moreover, we did not identify a second, indisputable independent genetic diagnosis, related to pathogenic Copy Number Variations or rare pathogenic exonic variants in known ID/ASD causing genes, although several variants of unknown significance were found. Finally, imprinting effect does not appear to be the only cause of autism in WBS patients, since the deletions occurred in alleles of both maternal and paternal origin.

The social disinhibition observed in WBS does not follow common social norms and symptoms overlapping with ASD, such as restricted interests and repetitive behavior, can be observed in “typical” WBS patients: therefore, the terms “overfriendliness” and “hypersociability” appear to be a misleading oversimplification.

The etiology of ASD in WBS is likely to be heterogeneous. Further studies on large series of patients are needed to clarify the observed variability in WBS social communication, ranging from excessive talkativeness and social disinhibition to absence of verbal language and social deficit.

Elastin-driven genetic diseases

Elastic fibers provide recoil to tissues that undergo repeated deformation, such as blood vessels, lungs and skin. Composed of elastin and its accessory proteins, the fibers are produced within a restricted developmental window and are stable for decades. Their eventual breakdown is associated with a loss of tissue resiliency and aging. Rare alteration of the elastin (ELN) gene produces disease by impacting protein dosage (supravalvar aortic stenosis, Williams Beuren syndrome and Williams Beuren region duplication syndrome) and protein function (autosomal dominant cutis laxa). This review highlights aspects of the elastin molecule and its assembly process that contribute to human disease and also discusses potential therapies aimed at treating diseases of elastin insufficiency.

Oral prednisolone for management of persistent hypercalcemia afterhypercalcemic crisis in the Williams-Beuren syndrome

Hypercalcemia may occur in approximately 15% of children with the Williams-Beuren syndrome. The episodes of hypercalcemic crisis usually respond well to initial hyperhydration, loop diuretics and calcitonin, bisphosphonates, or subsequent dialysis. However, many patients suffer from recurrent or persistent hypercalcemia after the resolution of the hypercalcemic crisis. Although hypercalcemia in the Williams-Beuren syndrome is generally considered transient, it may last for several months, result in significant morbidity, and compromise physical growth. There are no guidelines for the management of persistent or recurrent hypercalcemia in patients with the Williams-Beuren syndrome. In this report, we describe our experience of conducting oral corticosteroid therapy in a child with the Williams-Beuren syndrome who continued to have hypercalcemia after the resolution of the hypercalcemic crisis.

People with intellectual disability: what do we know about adulthood and life expectancy?

Increases in the life expectancy of people with Intellectual Disability have followed similar trends to those found in the general population. With the exception of people with severe and multiple disabilities or Down syndrome, the life expectancy of this group now closely approximates with that of the general population. Middle and old age, which until 30 years ago were not recognized in this population, are now important parts of the life course of these individuals. Older adults with Intellectual Disabilities form a small, but significant and growing proportion of older people in the community. How these persons grow older and how symptoms and complications of the underlying cause of the Intellectual Disability will influence their life expectancy is of the utmost importance.