Genetic Testing for Supravalvar Aortic Stenosis: What to Do When It Is Not Williams Syndrome.

BACKGROUND: We aimed to describe the frequency and yield of genetic testing in supravalvar aortic stenosis (SVAS) following negative evaluation for Williams-Beuren syndrome (WS). METHODS AND RESULTS: This retrospective cohort study included patients with SVAS at our institution who had a negative evaluation for WS from May 1991 to September 2021. SVAS was defined as (1) peak supravalvar velocity of ≥2 meters/second, (2) sinotubular junction or ascending aortic Z score <-2.0, or (3) sinotubular junction Z score <-1.5 with family history of SVAS. Patients with complex congenital heart disease, aortic valve disease as the primary condition, or only postoperative SVAS were excluded. Genetic testing and diagnoses were reported. Of 162 patients who were WS negative meeting inclusion criteria, 61 had genetic testing results available (38%). Chromosomal microarray had been performed in 44 of 61 and was nondiagnostic for non-WS causes of SVAS. Sequencing of 1 or more genes was performed in 47 of 61. Of these, 39 of 47 underwent ELN sequencing, 20 of 39 (51%) of whom had a diagnostic variant. Other diagnoses made by gene sequencing were Noonan syndrome (3 PTPN11, 1 RIT1), Alagille syndrome (3 JAG1), neurofibromatosis (1 NF1), and homozygous familial hypercholesterolemia (1 LDLR1). Overall, sequencing was diagnostic in 29 of 47 (62%). CONCLUSIONS: When WS is excluded, gene sequencing for SVAS is high yield, with the highest yield for the ELN gene. Therefore, we recommend gene sequencing using a multigene panel or exome analysis. Hypercholesterolemia can also be considered in individuals bearing the stigmata of this disease.

Neuronal deletion of Gtf2i results in developmental microglial alterations in a mouse model related to Williams syndrome.

Williams syndrome (WS) is a genetic neurodevelopmental disorder caused by a heterozygous microdeletion, characterized by hypersociability and unique neurocognitive abnormalities. Of the deleted genes, GTF2I has been linked to hypersociability in WS. We have recently shown that Gtf2i deletion from forebrain excitatory neurons, referred to as Gtf2i conditional knockout (cKO) mice leads to multi-faceted myelination deficits associated with the social behaviors affected in WS. These deficits were potentially mediated also by microglia, as they present a close relationship with oligodendrocytes. To study the impact of altered myelination, we characterized these mice in terms of microglia over the course of development. In postnatal day 30 (P30) Gtf2i cKO mice, cortical microglia displayed a more ramified state, as compared with wild type (controls). However, postnatal day 4 (P4) microglia exhibited high proliferation rates and an elevated activation state, demonstrating altered properties related to activation and inflammation in Gtf2i cKO mice compared with control. Intriguingly, P4 Gtf2i cKO-derived microglial cells exhibited significantly elevated myelin phagocytosis in vitro compared to control mice. Lastly, systemic injection of clemastine to P4 Gtf2i cKO and control mice until P30, led to a significant interaction between genotypes and treatments on the expression levels of the phagocytic marker CD68, and a significant reduction of the macrophage/microglial marker Iba1 transcript levels in the cortex of the Gtf2i cKO treated mice. Our data thus implicate microglia as important players in WS, and that early postnatal manipulation of microglia might be beneficial in treating inflammatory and myelin-related pathologies.

Pragmatic skills in people with Williams syndrome: the perception of families.

BACKGROUND: One of the most challenging linguistic areas in people with Williams Syndrome throughout their evolutionary stage is the development of pragmatic skills. The research conducted so far highlights specific problems concerning adaptation to the linguistic context and interlocutors, language comprehension, as well as other aspects interfering with verbal communication. However, until now, most scientific evidence has been based on personal assessments of this group. In a complementary manner, the goal of this study was to discover the level of pragmatic skills of people with Williams Syndrome from the point of view of the families. The sample consisted of 34 families belonging to the Williams Syndrome Association of Spain. The assessment instrument was the pragmatic awareness questionnaire, which includes 26 items related to different aspects that are part of the pragmatic area on a Likert-type scale. RESULTS: The results indicate that, families consider there to be a regular to low level in all the areas assessed. The strong points seem to lie in the paralinguistic aspects, while the weakest factors are those related to the understanding of figurative language. CONCLUSIONS: Therefore, it is necessary to continue insisting on the importance of language intervention in this group throughout its development to improve its level of linguistic competence.

Development of a Low Cost Semiquantitative Polymerase Chain Reaction Assay for Molecular Diagnosis of Williams Syndrome.

BACKGROUND: Williams Beuren Syndrome (WBS) is a well-recognized and common genetic cause of congenital heart defects, developmental delay, hypercalcemia, and characteristic facial features. It is caused by a 1.5 - 1.8 Mb heterozygous deletion of chromosome 7q11.23 with loss of around 28 coding genes. The aim of this study was to develop a low-cost, semi-quantitative PCR (sqPCR) method to detect the chromosome 7q11.23 deletion. METHODS: Twenty-four suspected WBS cases were recruited following ethical clearance and informed consent. Blood was obtained, DNA extracted and spectrophotometrically quantified using standard methods. To detect the deletion by dosage analysis, a target region within a gene located in the WBS commonly deleted region of 7q11.23 was amplified together with a control region in a duplex sqPCR assay. The control region was telomeric to the WBS commonly deleted region and was located in chromosome 7q31.2. The two target regions within the deleted region namely a locus within ELN and a marker in the intergenic region between FZD9 and FKBP6 and designated IFF, were amplified in separate duplex sqPCR assays. The Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene was used as the control for normalization. Included in the assay were a non-deleted and deleted individuals' samples. RESULTS: Nineteen patients were identified to have the deletion while five did not. All 24 patients' results were confirmed by whole exome sequencing and 11 also by fluorescence in-situ hybridization (FISH). CONCLUSIONS: The data obtained indicates the sqPCR assay developed in this study to be an accurate and reliable diagnostic test for WBS. Most Sri Lankan patients with WBS are diagnosed clinically, as many parents of affected WBS children are unable to afford currently available molecular diagnostic testing. This low cost sqPCR test is therefore likely to benefit Sri Lankan WBS patients, by enabling genetic testing for confirming or refuting a clinical diagnosis of WBS and may be of use in other low and middle income countries.

Loss of GTF2I promotes neuronal apoptosis and synaptic reduction in human cellular models of neurodevelopment.

Individuals with Williams syndrome (WS), a neurodevelopmental disorder caused by hemizygous loss of 26-28 genes at 7q11.23, characteristically portray a hypersocial phenotype. Copy-number variations and mutations in one of these genes, GTF2I, are associated with altered sociality and are proposed to underlie hypersociality in WS. However, the contribution of GTF2I to human neurodevelopment remains poorly understood. Here, human cellular models of neurodevelopment, including neural progenitors, neurons, and three-dimensional cortical organoids, are differentiated from CRISPR-Cas9-edited GTF2I-knockout (GTF2I-KO) pluripotent stem cells to investigate the role of GTF2I in human neurodevelopment. GTF2I-KO progenitors exhibit increased proliferation and cell-cycle alterations. Cortical organoids and neurons demonstrate increased cell death and synaptic dysregulation, including synaptic structural dysfunction and decreased electrophysiological activity on a multielectrode array. Our findings suggest that changes in synaptic circuit integrity may be a prominent mediator of the link between alterations in GTF2I and variation in the phenotypic expression of human sociality.

Williams-Beuren syndrome in pediatric T-cell acute lymphoblastic leukemia: A rare case report and review of literature.

BACKGROUND: Williams-Beuren syndrome (WBS) is a rare genetic disorder caused by hemizygous microdeletion of contiguous genes on chromosome 7q11.23. Although the phenotype features extensive heterogeneity in severity and performance, WBS is not considered to be a predisposing factor for cancer development. Currently, hematologic cancers, mainly Burkitt lymphoma, are rarely reported in patients with WBS. Here in, we report a unique case of T-cell acute lymphoblastic leukemia in a male child with WBS. METHODS: This retrospective study analyzed the clinical data of this case receiving chemotherapy were analyzed. This is a retrospective study. RESULTS: The patient, who exhibited a typical WBS phenotype and presented with hemorrhagic spots. Chromosomal genome-wide chip analysis (CMA) revealed abnormalities on chromosomes 7 and 9. The fusion gene STIL-TAL1 and mutations in BCL11B, NOTCH1, and USP7 have also been found and all been associated with the occurrence of T-cell leukemia. The patient responded well to the chemotherapy. CONCLUSION: To the best of our knowledge, this is the first reported case of WBS in T-cell acute lymphoblastic leukemia. We want to emphasize that the occurrence of leukemia in this patient might be related to the loss of 7q11.23 and microdeletion of 9p21.3 (including 3 TSGs), but the relationship between WBS and malignancy remains unclear. Further studies are required to clarify the relationship between WBS and malignancy.

Syntaxin1A overexpression and pain insensitivity in individuals with 7q11.23 duplication syndrome.

Genetic modifications leading to pain insensitivity phenotypes, while rare, provide invaluable insights into the molecular biology of pain and reveal targets for analgesic drugs. Pain insensitivity typically results from Mendelian loss-of-function mutations in genes expressed in nociceptive (pain-sensing) dorsal root ganglion (DRG) neurons that connect the body to the spinal cord. We document a pain insensitivity mechanism arising from gene overexpression in individuals with the rare 7q11.23 duplication syndrome (Dup7), who have 3 copies of the approximately 1.5-megabase Williams syndrome (WS) critical region. Based on parental accounts and pain ratings, people with Dup7, mainly children in this study, are pain insensitive following serious injury to skin, bones, teeth, or viscera. In contrast, diploid siblings (2 copies of the WS critical region) and individuals with WS (1 copy) show standard reactions to painful events. A converging series of human assessments and cross-species cell biological and transcriptomic studies identified 1 likely candidate in the WS critical region, STX1A, as underlying the pain insensitivity phenotype. STX1A codes for the synaptic vesicle fusion protein syntaxin1A. Excess syntaxin1A was demonstrated to compromise neuropeptide exocytosis from nociceptive DRG neurons. Taken together, these data indicate a mechanism for producing "genetic analgesia" in Dup7 and offer previously untargeted routes to pain control.

Buspirone for the treatment of anxiety in Williams syndrome: a retrospective chart review study.

BACKGROUND: Williams syndrome (WS) is a rare genetic disorder associated with a high prevalence of anxiety disorders. Evidence-based pharmacologic treatments for anxiety in WS are lacking. The purpose of this study is to provide naturalistic data on the use of buspirone for the treatment of anxiety in WS. RESEARCH DESIGN AND METHODS: Medical records of 24 individuals with Williams syndrome (ages 7-47 years) and anxiety who received treatment with buspirone were reviewed. Treatment response to buspirone was rated by assigning a retrospective Clinical Global Impression Improvement subscale (CGI-I) score. RESULTS: Twenty-three of 24 (96%) patients completed at least a 16-week treatment course with buspirone. Sixteen patients (67%; 95% CI 47%, 82%) were treatment responders (CGI-I ≤ 2). Only 1 (4%) patient discontinued buspirone due to a treatment-emergent side effect (nausea and vomiting). The most common side effect was nausea (13%). Twenty (84%) patients remained on buspirone at the time of their most recent follow-up visit. CONCLUSIONS: In this retrospective study, the majority of patients responded to a 16-week course of buspirone. Prospective studies are warranted to further assess the efficacy and tolerability of buspirone for anxiety in WS.

Matrisome and Immune Pathways Contribute to Extreme Vascular Outcomes in Williams-Beuren Syndrome.

BACKGROUND: Supravalvar aortic stenosis (SVAS) is a characteristic feature of Williams-Beuren syndrome (WBS). Its severity varies: ~20% of people with Williams-Beuren syndrome have SVAS requiring surgical intervention, whereas ~35% have no appreciable SVAS. The remaining individuals have SVAS of intermediate severity. Little is known about genetic modifiers that contribute to this variability. METHODS AND RESULTS: We performed genome sequencing on 473 individuals with Williams-Beuren syndrome and developed strategies for modifier discovery in this rare disease population. Approaches include extreme phenotyping and nonsynonymous variant prioritization, followed by gene set enrichment and pathway-level association tests. We next used GTEx v8 and proteomic data sets to verify expression of candidate modifiers in relevant tissues. Finally, we evaluated overlap between the genes/pathways identified here and those ascertained through larger aortic disease/trait genome-wide association studies. We show that SVAS severity in Williams-Beuren syndrome is associated with increased frequency of common and rarer variants in matrisome and immune pathways. Two implicated matrisome genes (ACAN and LTBP4) were uniquely expressed in the aorta. Many genes in the identified pathways were previously reported in genome-wide association studies for aneurysm, bicuspid aortic valve, or aortic size. CONCLUSIONS: Smaller sample sizes in rare disease studies necessitate new approaches to detect modifiers. Our strategies identified variation in matrisome and immune pathways that are associated with SVAS severity. These findings suggest that, like other aortopathies, SVAS may be influenced by the balance of synthesis and degradation of matrisome proteins. Leveraging multiomic data and results from larger aorta-focused genome-wide association studies may accelerate modifier discovery for rare aortopathies like SVAS.

Concurrent predictors of mathematics achievement for 9-year-old children with Williams syndrome.

Research on mathematics achievement by children with Williams syndrome (WS) has been very limited. We describe the math achievement of 72 9-year-olds with WS, compare their math and reading achievement, and explore concurrent predictors of math achievement using the Wechsler Individual Achievement Test-III (WIAT-III) to measure achievement and the Differential Ability Scales-II (DAS-II) to measure cognitive abilities. For both Numerical Operations and Math Problem Solving, mean standard scores (SSs) were in the mild disability range with a full range from severe disability to average ability. Bayesian robust estimation indicated decisive evidence that average reading performance was higher than average math performance. Bayesian multiple linear regression models with informative priors accounted for 60% of the variance in Numerical Operations SS with decisive evidence supporting an effect of Working Memory SS and strong evidence for Nonverbal Reasoning SS and Spatial SS and 71% of the variance in Math Problem Solving SS with decisive evidence supporting effects of Working Memory and Nonverbal Reasoning SS, strong evidence for Verbal SS, and substantial evidence for Spatial SS. These predictors are consistent with those for typically developing individuals, supporting consideration of interventions that have been highly effective for children with math difficulties in the general population.

Evaluating the challenges and needs of parents caring for children with Williams syndrome: A preliminary study from Poland.

BACKGROUND: Although physical, cognitive and behavioural manifestations of Williams syndrome (WS) affect every dimension of caregivers lives, no studies on the parental experiences of caring for a WS child have to date been carried out in Poland. METHODS: In order to identify the challenges and needs of Polish carers of WS children a survey was conducted with 32 family caregivers who were supported by the Polish Williams Syndrome Association. RESULTS: While caregivers were mostly challenged by their WS child's behaviours, health problems and mood swings, many parents experienced fatigue, intimacy problems with the partner and deterioration of mental health. They were also burdened by the lack of time for themselves and work restrictions resulting from caregiving responsibilities. Even though parents positively assessed quality of medical care for WS children, still many expressed their dissatisfaction both with the way the healthcare system for WS children works in Poland and complained about the doctors' lack of knowledge about WS, access to specialist care and lack of support from government and social institutions. Although many parents stressed positive impact of rising WS child, more than half experienced role captivity or role overload and felt not being understood by others. They also experienced variety of distressing emotions, including impatience, emotional lability, helplessness, anxiety and depression. CONCLUSIONS: Although many WS parents stressed the affirmative aspect of raising WS child this research shows that the burden of caring for such a child goes far beyond clinical aspects and seriously affects every aspect of parents' lives, including their mental health, daily lives, family, their professional and social lives. Because apart from the daily challenges related to caring for a WS child, parents' dealings with the healthcare system and support services represent major problems there is a the need for a bio-psychosocial approach to WS that should include not only WS children, but also their caregivers. WHAT THIS PAPER ADDS?: 1. It analyses the challenges and needs of parents caring for children with Williams syndrome; 2. It provides evidence that the impact of caring for WS children goes far beyond clinical aspects and seriously affects every aspect of parents' lives, including their mental health, daily lives, family, their professional and social lives; 3. It also shows that, apart from the daily challenges related to caring for a WS child, parents' dealings with the healthcare system and support services represent major problems. 4. Thereby, it highlights the importance of incorporating a bio-psychosocial approach to WS that should include not only WS children, but also their caregivers.

Electrocardiograms Do Not Detect Myocardial Ischemia in Patients With Williams Syndrome and Nonsyndromic Elastin Arteriopathy With Coronary Artery Stenosis.

Coronary artery stenosis (CAS) may affect up to 27% of patients with Williams syndrome (WS), which may lead to myocardial ischemia. Patients with WS face a 25- to 100-fold greater risk of sudden cardiac death, frequently linked to anesthesia. Assessing CAS requires either imaging while under general anesthesia or intraoperative assessment, with the latter considered the gold standard. Our study aimed to identify electrocardiogram (ECG) markers of myocardial ischemia in patients with WS or nonsyndromic elastin arteriopathy and documented CAS. We retrospectively reviewed patients with WS/elastin arteriopathy who underwent supravalvar aortic stenosis surgery and CAS assessment from January 1, 2006 to April 30, 2021. A pediatric electrophysiologist, not aware of the patients' CAS status, reviewed their preoperative ECGs for markers of ischemia. We assessed associations of study parameters using Wilcoxon rank-sum and Fisher's exact tests. Of 34 patients, 62% were male, with a median age of 20 months (interquartile range: 8 to 34). CAS was present in 62% (21 of 34), 76% of whom (16 of 21) were male. There were no ECG indicators of myocardial ischemia in patients with CAS. In conclusion, CAS was present in >1/2 the children with WS/elastin arteriopathy who underwent repair of supravalvar aortic stenosis. CAS in WS/nonsyndromic elastin arteriopathy does not appear to exhibit typical ECG-detectable myocardial ischemia. ECGs are not a useful screening tool for CAS in WS/elastin arteriopathy. Given the high anesthesia-related cardiac arrest risk, other noninvasive indicators of CAS are needed.

Intensive Care Unit Analgosedation After Cardiac Surgery in Children with Williams Syndrome : a Matched Case-Control Study.

OBJECTIVE: Cardiovascular abnormalities are common in patients with Williams syndrome and frequently require surgical intervention necessitating analgesia and sedation in a population with a unique neuropsychiatric profile, potentially increasing the risk of adverse cardiac events during the perioperative period. Despite this risk, the overall postoperative analgosedative requirements in patients with WS in the cardiac intensive care unit have not yet been investigated. Our primary aim was to examine the analgosedative requirement in patients with WS after cardiac surgery compared to a control group. Our secondary aim was to compare the frequency of major ACE and mortality between the two groups. DESIGN: Matched case-control study. SETTING: Pediatric CICU at a Tertiary Children's Hospital. PATIENTS: Patients with WS and age-matched controls who underwent cardiac surgery and were admitted to the CICU after cardiac surgery between July 2014 and January 2021. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Postoperative outcomes and total doses of analgosedative medications were collected in the first six days after surgery for the study groups. Median age was 29.8 (12.4-70.8) months for WS and 23.5 (11.2-42.3) months for controls. Across all study intervals (48 h and first 6 postoperative days), there were no differences between groups in total doses of morphine equivalents (5.0 mg/kg vs 5.6 mg/kg, p = 0.7 and 8.2 mg/kg vs 10.0 mg/kg, p = 0.7), midazolam equivalents (1.8 mg/kg vs 1.5 mg/kg, p = 0.4 and 3.4 mg/kg vs 3.8 mg/kg, p = 0.4), or dexmedetomidine (20.5 mcg/kg vs 24.4 mcg/kg, p = 0.5 and 42.3 mcg/kg vs 39.1 mcg/kg, p = 0.3). There was no difference in frequency of major ACE or mortality. CONCLUSIONS: Patients with WS received similar analgosedative medication doses compared with controls. There was no significant difference in the frequency of major ACE (including cardiac arrest, extracorporeal membrane oxygenation, and surgical re-intervention) or mortality between the two groups, though these findings must be interpreted with caution. Further investigation is necessary to elucidate the adequacy of pain/sedation control, factors that might affect analgosedative needs in this unique population, and the impact on clinical outcomes.

Psychiatric and behavioral manifestations of Williams syndrome.

PURPOSE OF REVIEW: The purpose of this review is to synthesize recent advances in the psychiatric and behavioral manifestations of Williams syndrome, a rare genetic syndrome. Recent advances have focused on more deeply characterizing the social phenotype and developing social skill interventions, improving the assessment and treatment of anxiety, and exploring eating behaviors. RECENT FINDINGS: The social cognitive phenotype in Williams syndrome, which consists of both high social drive and social cognition deficits, is present cross-culturally and may be related to reduced eye gaze. Social skills training for adults with Williams syndrome has demonstrated promise. Adapted exposure therapy and cognitive behavioral therapy programs for children and adults respectively, have been piloted in Williams syndrome. The majority of adults with Williams syndrome are either underweight or overweight, and problematic food-related behaviors likely contribute to bodyweight status. SUMMARY: Williams syndrome is associated with a number of core social and psychiatric difficulties which have a significant impact on functioning and quality of life. Recent work has begun to utilize a more nuanced understanding of the clinical presentations of these problems to develop interventions tailored to this unique population. However, larger trials, particularly those inclusive of a more diverse Williams syndrome population, are needed.

Transposons in the Williams-Beuren Syndrome Critical Region are Associated with Social Behavior in Assistance Dogs.

A strong signature of selection in the domestic dog genome is found in a five-megabase region of chromosome six in which four structural variants derived from transposons have previously been associated with human-oriented social behavior, such as attentional bias to social stimuli and social interest in strangers. To explore these genetic associations in more phenotypic detail-as well as their role in training success in a specialized assistance dog program-we genotyped 1001 assistance dogs from Canine Companions for Independence®, including both successful graduates and dogs released from the training program for behaviors incompatible with their working role. We collected phenotypes on each dog using puppy-raiser questionnaires, trainer questionnaires, and both cognitive and behavioral tests. Using Bayesian mixed models, we found strong associations (95% credibility intervals excluding zero) between genotypes and certain behavioral measures, including separation-related problems, aggression when challenged or corrected, and reactivity to other dogs. Furthermore, we found moderate differences in the genotypes of dogs who graduated versus those who did not; insertions in GTF2I showed the strongest association with training success (ß = 0.23, CI95% = - 0.04, 0.49), translating to an odds-ratio of 1.25 for one insertion. Our results provide insight into the role of each of these four transposons in canine sociability and may inform breeding and training practices for working dog organizations. Furthermore, the observed importance of the gene GTF2I supports the emerging consensus that variation in GTF2I genotypes and expression have important consequences for social behavior broadly.

Fatal cardiac dysfunction in a child with Williams syndrome.

Williams syndrome (WS) is a rare genetic disorder caused by a microdeletion of chromosome 7q11.23. Although the mortality rate of patients with WS is not very high, sudden cardiac death can occur, particularly in cases complicated by coronary artery stenosis. A 3-month-old female infant with supravalvular aortic stenosis and peripheral pulmonary stenosis was discovered unconscious in bed by her mother. She was immediately transferred to an emergency hospital but succumbed despite multiple attempts as resuscitation. DNA microarray analysis revealed microdeletions of 7q11.23 and 16p11.2, confirming WS and unexpectedly identifying 16p11.2 deletion syndrome which is known to be associated with neurodevelopmental disorders. Postmortem computed tomography revealed a severely enlarged heart, indicative of cardiac dysfunction. External examination revealed moderate-to-severe developmental delays in height and body weight. The heart, on internal examination, revealed whitish-discolored lesions; histologically severe fibrotic changes and thickening of the intima in the coronary arteries and aorta. In the brain, the dentate gyrus of the hippocampus appeared malformed. Taken together, these findings suggest that the cause of death was cardiac dysfunction due to WS. In addition, it could be possible that 16p11.2 deletion syndrome and dentate gyrus malformation contributed to her death. Future autopsy studies are warranted to clarify the precise role of microdeletion disorders in sudden death to reduce future preventable deaths in children.

Cross-sectional and longitudinal assessment of cognitive development in Williams syndrome.

Williams syndrome (WS) is a rare genetic syndrome. As with all rare syndromes, obtaining adequately powered sample sizes is a challenge. Here we present legacy data from seven UK labs, enabling the characterisation of cross-sectional and longitudinal developmental trajectories of verbal and non-verbal development in the largest sample of individuals with WS to-date. In Study 1, we report cross-sectional data between N = 102 and N = 209 children and adults with WS on measures of verbal and non-verbal ability. In Study 2, we report longitudinal data from N = 17 to N = 54 children and adults with WS who had been tested on at least three timepoints on these measures. Data support the WS characteristic cognitive profile of stronger verbal than non-verbal ability, and shallow developmental progression for both domains. Both cross-sectional and longitudinal data demonstrate steeper rates of development in the child participants than the adolescent and adults in our sample. Cross-sectional data indicate steeper development in verbal than non-verbal ability, and that individual differences in the discrepancy between verbal and non-verbal ability are largely accounted for by level of intellectual functioning. A diverging developmental discrepancy between verbal and non-verbal ability, whilst marginal, is not mirrored statistically in the longitudinal data. Cross-sectional and longitudinal data are discussed with reference to validating cross-sectional developmental patterns using longitudinal data and the importance of individual differences in understanding developmental progression.

Loss of Baz1b in mice causes perinatal lethality, growth failure, and variable multi-system outcomes.

BAZ1B is one of 25-27 coding genes deleted in canonical Williams syndrome, a multi-system disorder causing slow growth, vascular stenosis, and gastrointestinal complaints, including constipation. BAZ1B is involved in (among other processes) chromatin organization, DNA damage repair, and mitosis, suggesting reduced BAZ1B may contribute to Williams syndrome symptoms. In mice, loss of Baz1b causes early neonatal death. 89.6% of Baz1b-/- mice die within 24 h of birth without vascular anomalies or congenital heart disease (except for patent ductus arteriosus). Some (<50%) Baz1b-/- were noted to have prolonged neonatal cyanosis, patent ductus arteriosus, or reduced lung aeration, and none developed a milk spot. Meanwhile, 35.5% of Baz1b+/- mice die over the first three weeks after birth. Surviving Baz1b heterozygotes grow slowly (with variable severity). 66.7% of Baz1b+/- mice develop bowel dilation, compared to 37.8% of wild-type mice, but small bowel and colon transit studies were normal. Additionally, enteric neuron density appeared normal in Baz1b-/- mice except in distal colon myenteric plexus, where neuron density was modestly elevated. Combined with several rare phenotypes (agnathia, microphthalmia, bowel dilation) recovered, our work confirms the importance of BAZ1B in survival and growth and suggests that reduced copy number of BAZ1B may contribute to the variability in Williams syndrome phenotypes.

Strategies for the Surgical Management of Highly Aggressive Williams Syndrome Aortopathy: A Three Case Report.

Severe aortopathy in Williams syndrome can sometimes present with an initial ascending aortic pathology, followed in short order by more distal multilevel obstruction and recurrence requiring reintervention. In this series, an early, comprehensive surgical approach using a combination of various access and perfusion strategies yielded excellent long-term results.

Neuronal Gtf2i deletion alters mitochondrial and autophagic properties.

Gtf2i encodes the general transcription factor II-I (TFII-I), with peak expression during pre-natal and early post-natal brain development stages. Because these stages are critical for proper brain development, we studied at the single-cell level the consequences of Gtf2i's deletion from excitatory neurons, specifically on mitochondria. Here we show that Gtf2i's deletion resulted in abnormal morphology, disrupted mRNA related to mitochondrial fission and fusion, and altered autophagy/mitophagy protein expression. These changes align with elevated reactive oxygen species levels, illuminating Gtf2i's importance in neurons mitochondrial function. Similar mitochondrial issues were demonstrated by Gtf2i heterozygous model, mirroring the human condition in Williams syndrome (WS), and by hemizygous neuronal Gtf2i deletion model, indicating Gtf2i's dosage-sensitive role in mitochondrial regulation. Clinically relevant, we observed altered transcript levels related to mitochondria, hypoxia, and autophagy in frontal cortex tissue from WS individuals. Our study reveals mitochondrial and autophagy-related deficits shedding light on WS and other Gtf2i-related disorders.