Growth, body composition, and endocrine issues in Williams syndrome

Characterization of the Prenatal Ultrasound Phenotype Associated With 7q11.23 Microduplication Syndrome and Williams-Beuren Syndrome

OBJECTIVE

This study aimed to characterize the intrauterine phenotype of fetuses with 7q11.23 microduplication syndrome and Williams-Beuren syndrome (WBS) to provide insight into prenatal genotype and phenotype correlations in the 7q11.23 region.

METHODS

Seven fetuses with 7q11.23 microduplication syndrome and sixteen with WBS were diagnosed via array comparative genomic hybridization (array CGH) or copy number variation sequencing (CNV-seq) at our center. Clinical data were also systematically collected and analyzed, including intrauterine phenotype, pregnancy outcome, and inheritance.

RESULTS

In our cases, the most common prenatal ultrasound feature of 7q11.23 microduplication syndrome was cardiovascular defects; less frequent features included choroid plexus cysts, anencephaly, bilateral pyelectasis, and cervical lymphatic hygroma. On the other hand, WBS was mainly associated with cardiovascular defects and intrauterine growth retardation. Other clinical phenotypes included hypoechoic frontal horn of the right lateral ventricle, crossed fused renal ectopia, hyperechogenic bowel, hyperechogenic right thoracic cavity, and hyperechogenic hepatic parenchyma/intrahepatic duct wall.

CONCLUSIONS

Our study describes a series of new ultrasound features identified prenatally in fetuses with 7q11.23 microduplications and microdeletions with the intent of expanding the prenatal phenotype associated with copy number variants in this chromosomal region. Additional studies are needed to clearly delineate specific prenatal features associated with these rare genetic entities.

Brazilian growth charts for Williams-Beuren Syndrome at ages 2 to 18 years

OBJECTIVE

To develop growth charts for weight-for-age, height-for-age, and body mass index (BMI)-for-age for both genders aged 2 to 18 years for Brazilian patients with Williams-Beuren Syndrome (WBS).

METHODS

This is a multicenter, retrospective, and longitudinal study, data were collected from the medical records of boys and girls with a confirmed diagnosis of WBS in three large university centers in the state of Sao Paulo, Brazil. Growth charts stratified by gender and age in years were developed using LMSchartmaker Pro software. The LMS (Lambda Mu Sigma) method was used to model the charts . The quality of the settings was checked by worm plots.

RESULTS

The first Brazilian growth charts for weight-for-age, height-for-age, and BMI-for-age stratified by gender were constructed for WBS patients aged 2 to 18 years.

CONCLUSION

The growth charts developed in this study can help to guide family members and to improve the health care offered by health professionals.

Case Report: Rapid and progressive left ventricular endocardial calcification in an infant with Williams syndrome

Williams syndrome (WS) is characterized by a range of clinical features, including cardiovascular disease, distinctive facial traits, neurobehavioral disorders, and a condition known as transient infantile hypercalcemia. Among these, endocardial calcification represents a non-specific response to severe, etiologically diverse myocardial injuries. In this report, we document a unique case involving an infant with WS who exhibited rapidly progressive arterial stenosis and left ventricular endocardial calcification, associated with a novel heterozygous deletion. While arterial stenosis is the most frequently observed cardiovascular issue in WS, instances of endocardial calcification during infancy are exceedingly rare and have not previously been reported in the context of WS.

Altered pubertal timing in 7q11.23 copy number variations and associated genetic mechanisms

Pubertal timing, including age at menarche (AAM), is a heritable trait linked to lifetime health outcomes. Here, we investigate genetic mechanisms underlying AAM by combining genome-wide association study (GWAS) data with investigations of two rare genetic conditions clinically associated with altered AAM: Williams syndrome (WS), a 7q11.23 hemideletion characterized by early puberty; and duplication of the same genes (7q11.23 Duplication syndrome [Dup7]) characterized by delayed puberty. First, we confirm that AAM-derived polygenic scores in typically developing children (TD) explain a modest amount of variance in AAM (R2 = 0.09; p = 0.04). Next, we demonstrate that 7q11.23 copy number impacts AAM (WS < TD < Dup7; p = 1.2x10-8, η2 = 0.45) and pituitary volume (WS < TD < Dup7; p = 3x10-5, ηp2 = 0.2) with greater effect sizes. Finally, we relate an AAM-GWAS signal in 7q11.23 to altered expression in postmortem brains of STAG3L2 (p = 1.7x10-17), a gene we also find differentially expressed with 7q11.23 copy number (p = 0.03). Collectively, these data explicate the role of 7q11.23 in pubertal onset, with STAG3L2 and pituitary development as potential mediators.

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.

Incidental Diagnosis of Williams Syndrome in an Adult With Recurrent Hypercalcemia

Williams syndrome (WS) is a rare genetic disorder with multisystem involvement associated with hypercalcemia. The cause of this hypercalcemia is poorly understood and while primarily associated with WS children, it is also observed in adults. A 51-year-old woman with intellectual disability, renal insufficiency, recurrent pancreatitis, and intermittent hypercalcemia despite partial parathyroidectomy presented with hypercalcemia to 14 mg/dL (3.49 mmol/L; normal 8.6-10.5 mg/dL [2.12-2.62 mmol/L]) at routine follow-up. Laboratory testing was notable for acute-on-chronic renal failure with unremarkable vitamin D, urine calcium, and parathyroid hormone. She presented to the emergency department and was admitted. Treatment with bisphosphonates, calcitonin, and intravenous fluids decreased calcium to 9.4 mg/dL (2.35 mmol/L) and improved kidney function. She was discharged with recommendations for increased oral hydration, a low-calcium diet, and outpatient follow-up. Her phenotype was suspicious for WS, later confirmed with genetic testing. This case exemplifies both the increased risk of hypercalcemia in WS adults and the need to consider WS in hypercalcemic adults with intellectual disability. It also serves to illustrate the importance of recognizing WS features in potentially undiagnosed adults and reviews guidelines for hypercalcemia surveillance and management in WS adults.

Prenatal diagnosis of 7q11.23 microdeletion: Two cases report and literature review

RATIONALE

Chromosome microdeletions within 7q11.23 can result in Williams-Beuren syndrome which is a rare autosomal dominant disorder. Williams-Beuren syndrome is usually associated with developmental delay, cardiovascular anomalies, mental retardation, and characteristic facial appearance.

PATIENT CONCERNS

Two pregnant women underwent amniocentesis for cytogenetic analysis and chromosomal microarray analysis (CMA) because of abnormal ultrasound findings. Case 1 presented subependymal cyst and case 2 presented intrauterine growth restriction, persistent left superior vena cava and pericardial effusion in clinical ultrasound examination.

DIAGNOSES

Cytogenetic examination showed that the 2 fetuses presented normal karyotypic results. CMA detected 1.536 Mb (case 1) and 1.409 Mb (case 2) microdeletions in the region of 7q11.23 separately.

INTERVENTIONS

Both couples opted for the termination of pregnancies based upon genetic counseling.

OUTCOMES

The deleted region in both fetuses overlapped with Williams-Beuren syndrome. To our knowledge, case 1 was the first reported fetus of Williams-Beuren syndrome with subependymal cyst.

LESSONS

The genotype-phenotype of Williams-Beuren syndrome is complicated due to the phenotypic diversity. For prenatal cases, clinicians should consider the combination of ultrasonography, traditional cytogenetic, and molecular diagnosis technology when genetic counseling.

Analysis of gut microbiota in patients with Williams-Beuren Syndrome reveals dysbiosis linked to clinical manifestations

Williams-Beuren syndrome (WBS) is a multisystem genetic disease caused by the deletion of a region of 1.5-1.8 Mb on chromosome 7q11.23. The elastin gene seems to account for several comorbidities and distinct clinical features such including cardiovascular disease, connective tissue abnormalities, growth retardation, and gastrointestinal (GI) symptoms. Increasing evidence points to alterations in gut microbiota composition as a primary or secondary cause of some GI or extra-intestinal characteristics. In this study, we performed the first exploratory analysis of gut microbiota in WBS patients compared to healthy subjects (CTRLs) using 16S rRNA amplicon sequencing, by investigating the gut dysbiosis in relation to diseases and comorbidities. We found that patients with WBS have significant dysbiosis compared to age-matched CTRLs, characterized by an increase in proinflammatory bacteria such as Pseudomonas, Gluconacetobacter and Eggerthella, and a reduction of anti-inflammatory bacteria including Akkermansia and Bifidobacterium. Microbial biomarkers associated with weight gain, GI symptoms and hypertension were identified. Gut microbiota profiling could represent a new tool that characterise intestinal dysbiosis to complement the clinical management of these patients. In particular, the administration of microbial-based treatments, alongside traditional therapies, could help in reducing or preventing the burden of these symptoms and improve the quality of life of these patients.

Clinical phenotypes study of 231 children with Williams syndrome in China: A single-center retrospective study

BACKGROUND

Williams syndrome (WS) is a multisystem neurodevelopmental disorder caused by microdeletions in 7q11.23. This study aims to characterize the clinical phenotypes of Chinese children with WS to help for the early diagnosis and intervention of this disease.

METHODS

231 children diagnosed with WS were retrospectively recruited to the study. Clinical data were analyzed to obtain the incidence of different clinical phenotypes. The occurrence of phenotypes and the influence of gender and age on the incidence of different phenotypes were analyzed.

RESULTS

All WS exhibited facial dysmorphism (100.0%). The majority had neurodevelopmental disorder (91.8%), hoarseness (87.4%) and cardiovascular anomalies (85.7%). The incidence of short stature (46.9%), inguinal hernia (47.2%), hypercalciuria (29.10%), hypercalcemia (9.1%), subclinical hypothyroidism (26.4%) and hypothyroidism (7.4%) were relatively higher. Gender differences were found in supravalvular aortic stenosis (SVAS, p < .001), ventricular septal defect (VSD, p < .05), inguinal hernia (p < .001), superior pulmonary stenosis (SVPS, p < .05) and neurodevelopmental disorder (p < .05). The incidence of neurodevelopmental disorder in WS increased with age (p < .05) while cardiovascular anomalies (p < .001), short stature (p < .001), hypercalciuria (p < .001) and hypercalcemia (p < .01) decreased with age.

CONCLUSIONS

Facial dysmorphism, neurodevelopmental disorder, hoarseness and cardiovascular anomalies were the most common phenotypes. Genetic testing should be suggested to confirm the diagnosis for children with the above abnormalities. Gender and age should be taken into account when making diagnosis and intervention.

Current Mechanistic Understandings of Lymphedema and Lipedema: Tales of Fluid, Fat, and Fibrosis

Lymphedema and lipedema are complex diseases. While the external presentation of swollen legs in lower-extremity lymphedema and lipedema appear similar, current mechanistic understandings of these diseases indicate unique aspects of their underlying pathophysiology. They share certain clinical features, such as fluid (edema), fat (adipose expansion), and fibrosis (extracellular matrix remodeling). Yet, these diverge on their time course and known molecular regulators of pathophysiology and genetics. This divergence likely indicates a unique route leading to interstitial fluid accumulation and subsequent inflammation in lymphedema versus lipedema. Identifying disease mechanisms that are causal and which are merely indicative of the condition is far more explored in lymphedema than in lipedema. In primary lymphedema, discoveries of genetic mutations link molecular markers to mechanisms of lymphatic disease. Much work remains in this area towards better risk assessment of secondary lymphedema and the hopeful discovery of validated genetic diagnostics for lipedema. The purpose of this review is to expose the distinct and shared (i) clinical criteria and symptomatology, (ii) molecular regulators and pathophysiology, and (iii) genetic markers of lymphedema and lipedema to help inform future research in this field.

Changes in elastin structure and extensibility induced by hypercalcemia and hyperglycemia

Elastin is a key elastomeric protein responsible for the elasticity of many organs, including heart, skin, and blood vessels. Due to its intrinsic long life and low turnover rate, damage in elastin induced by pathophysiological conditions, such as hypercalcemia and hyperglycemia, accumulates during biological aging and in aging-associated diseases, such as diabetes mellitus and atherosclerosis. Prior studies have shown that calcification induced by hypercalcemia deteriorates the function of aortic tissues. Glycation of elastin is triggered by hyperglycemia and associated with elastic tissue damage and loss of mechanical functions via the accumulation of advanced glycation end products. To evaluate the effects on elastin's structural conformations and elasticity by hypercalcemia and hyperglycemia at the molecular scale, we perform classical atomistic and steered molecular dynamics simulations on tropoelastin, the soluble precursor of elastin, under different conditions. We characterize the interaction sites of glucose and calcium and associated structural conformational changes. Additionally, we find that elevated levels of calcium ions and glucose hinder the extensibility of tropoelastin by rearranging structural domains and altering hydrogen bonding patterns, respectively. Overall, our investigation helps to reveal the behavior of tropoelastin and the biomechanics of elastin biomaterials in these physiological environments. STATEMENT OF SIGNIFICANCE: Elastin is a key component of elastic fibers which endow many important tissues and organs, from arteries and veins, to skin and heart, with strength and elasticity. During aging and aging-associated diseases, such as diabetes mellitus and atherosclerosis, physicochemical stressors, including hypercalcemia and hyperglycemia, induce accumulated irreversible damage in elastin, and consequently alter mechanical function. Yet, molecular mechanisms associated with these processes are still poorly understood. Here, we present the first study on how these changes in elastin structure and extensibility are induced by hypercalcemia and hyperglycemia at the molecular scale, revealing the essential roles that calcium and glucose play in triggering structural alterations and mechanical stiffness. Our findings yield critical insights into the first steps of hypercalcemia- and hyperglycemia-mediated aging.

Altered White Matter and microRNA Expression in a Murine Model Related to Williams Syndrome Suggests That miR-34b/c Affects Brain Development via Ptpru and Dcx Modulation

Williams syndrome (WS) is a multisystem neurodevelopmental disorder caused by a de novo hemizygous deletion of ~26 genes from chromosome 7q11.23, among them the general transcription factor II-I (GTF2I). By studying a novel murine model for the hypersociability phenotype associated with WS, we previously revealed surprising aberrations in myelination and cell differentiation properties in the cortices of mutant mice compared to controls. These mutant mice had selective deletion of Gtf2i in the excitatory neurons of the forebrain. Here, we applied diffusion magnetic resonance imaging and fiber tracking, which showed a reduction in the number of streamlines in limbic outputs such as the fimbria/fornix fibers and the stria terminalis, as well as the corpus callosum of these mutant mice compared to controls. Furthermore, we utilized next-generation sequencing (NGS) analysis of cortical small RNAs' expression (RNA-Seq) levels to identify altered expression of microRNAs (miRNAs), including two from the miR-34 cluster, known to be involved in prominent processes in the developing nervous system. Luciferase reporter assay confirmed the direct binding of miR-34c-5p to the 3'UTR of PTPRU-a gene involved in neural development that was elevated in the cortices of mutant mice relative to controls. Moreover, we found an age-dependent variation in the expression levels of doublecortin (Dcx)-a verified miR-34 target. Thus, we demonstrate the substantial effect a single gene deletion can exert on miRNA regulation and brain structure, and advance our understanding and, hopefully, treatment of WS.

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.