Cardiovascular and genitourinary anomalies in patients with duplications within the Williams syndrome critical region: Phenotypic expansion and review of the literature

Intrauterine phenotype features of fetuses with 7q11.23 microduplication syndrome

OBJECTIVE

To share our experience on prenatal diagnosis of 7q11.23 microduplication syndrome and to further delineate the fetal phenotypes of the syndrome.

METHODS

A retrospective study was conducted to evaluate seven cases of dup7q11.23 syndrome diagnosed prenatally by chromosomal microarray (CMA). Clinical data were reviewed, including maternal characteristics, indications for prenatal diagnosis, sonographic findings, CMA results, pregnancy outcomes and follow-ups.

RESULTS

Seven cases, including 2 pairs of MCDA twins, were prenatally identified with dup7q11.23 syndrome. The most common prenatal sonographic features were ventriculomegaly, low-lying conus medullaris, and dilated ascending aorta. All 7 fetuses presented with typical 7q11.23 duplications (1.40-1.55 Mb). Parental chromosome analysis was performed in four pairs of parents, and indicated that the duplications of Case 6 and 7 were inherited from their asymptomatic mother.

CONCLUSION

Our case series suggest that prenatal features of dup7q11.23 cases are diversified, with ventriculomegaly and low-lying conus medullaris being the most common intrauterine phenotypes. Additionally, cleft palate, dilated ascending aorta, and renal abnormalities were also observed, and should be taken into consideration in subsequent studies.

An Unusual Urological Manifestation of Williams-Beuren Syndrome: Posterior Urethral Valve

Williams-Beuren syndrome (WBS) is a genetic, well-defined, rare, neurodevelopmental disorder characterized by intellectual disability, congenital heart defects, abnormal facial features, and growth, endocrine, and genitourinary abnormalities. The genitourinary abnormalities in WBS frequently include congenital structural renal defects, vesicoureteral reflux, nephrocalcinosis, proteinuria, and chronic renal insufficiency. Treatment of patients with posterior urethral valve (PUV) remains a clinical challenge, requiring long-term management from early infancy into adulthood in order to avoid progressive renal insufficiency. To my knowledge, this is the first worldwide case of WBS with PUV in a 12-year-old boy. Due to the delayed detection of the defect, chronic renal disease occurred as a risk for him. This case demonstrates the importance of early diagnosis of genitourinary anomalies such as PUV to prevent chronic renal disease in boys and especially in patients with WBS.

Aortic Geometry in Patients with Duplication 7q11.23 Compared to Healthy Controls

The aim of this study was to compare the size and geometry of the aorta in patients with 7q11.23 duplication (Dup7) to healthy controls. We retrospectively reviewed all echocardiograms in all patients with Dup7 evaluated at our institutions from June 2017 through September 2019. All standard aortic diameter measurements were made and recorded. Z-scores for the measurements were calculated. For comparison, a set of control echocardiograms was developed by randomly selecting 24 normal echocardiograms in age-matched patients who had undergone echocardiograms for an indication of either chest pain or syncope. In 58 echocardiograms from 21 Dup7 patients, all aortic measurements were increased compared to controls (p < 0.0001). Effacement of the sinotubular junction (STJ) of the aorta was present in all Dup7 patients. Our novel STJ-to-aortic annulus ratio of ≥ 1.15 had a 98.28% sensitivity (95% CI 90.76-99.96) and 100% specificity (95% CI 85.75-100) for distinguishing Dup7 from controls with a positive predictive value of 100% and a negative predictive value of 96.00% (95% CI 77.47-99.41). All patients in our study with Dup7 had echocardiographic evidence of aortopathy. Effacement of the STJ was present in all Dup7 patients. The STJ-to-annulus ratio is a better indicator of aortopathy in Dup7 than the aortic Z-score.

Cardiac involvement in classical or hypermobile Ehlers-Danlos syndrome is uncommon

PURPOSE

Cardiac-valvular and vascular Ehlers-Danlos syndrome (EDS) have significant cardiovascular issues. The prevalence and significance of such abnormalities in classical (cEDS) or hypermobile EDS (hEDS) remain unclear. We report the prevalence of cardiac abnormalities in patients with cEDS and hEDS.

METHODS

We identified 532 pediatric patients with potential EDS evaluated at our institution from January 2014 through April 2019 by retrospective chart review. Ninety-five patients (12 cEDS and 83 hEDS patients) met 2017 EDS diagnostic criteria and had an echocardiogram. One patient was excluded due to complex congenital heart disease, and two were excluded due to lack of images. We reviewed echocardiograms for all structural abnormalities.

RESULTS

Of these 95 patients, 1 had mild aortic root dilation, and 1 had mild ascending aorta dilation in the setting of a bicuspid aortic valve. Eleven patients (11.6%) had a cardiac valve abnormality, all of which were trivial to mild. None of the patients required cardiac intervention.

CONCLUSION

Our results demonstrate that aortic dilation and valvular anomalies are uncommon in cEDS or hEDS patients. Given the lack of evidence, we do not recommend echocardiographic evaluation and surveillance in patients with cEDS and hEDS in the absence of clinical findings or positive family history.

Williams syndrome with severe hypercalcaemia

We present an 11-month-old girl child with complaints of constipation, cough, fever, vomiting and growth retardation. On examination, she had facial dysmorphism, hypertension and murmur. The genetic evaluation showed 7q microdeletion specific to Williams syndrome. Abdominal imaging was suggestive of nephrocalcinosis which is rare for this age group. The baby was managed symptomatically and specific treatment like pamidronate, calcitonin and steroid therapy were also administered to reduce hypercalcaemia. Severe hypercalcaemia with associated hypertension and nephrocalcinosis is very rare. Hence, we emphasise here the importance of early detection of these features and their appropriate management for a better outcome of the patient.

7q11.23 microduplication syndrome: neurophysiological and neuroradiological insights into a rare chromosomal disorder

BACKGROUND

The phenotypical consequence of the heterozygous chromosome 7q11.23 interstitial microdeletion is the Williams-Beuren syndrome, a very well-known genetic multi-systemic disorder. Much less is known about the reverse condition, the heterozygous interstitial microduplication of 7q11.23 region. The first molecular cytogenetic description was published in 2005, and only after several years were the reported patients numerous enough to attempt a description of a common phenotype.

METHOD

By using a broad multidisciplinary approach, we investigated 12 patients with this rare genetic anomaly. Ten of them harboured the duplication of the classical Williams-Beuren syndrome region and two a slightly larger duplication. Upon a detailed description of the clinical and psychological features, we used electroencephalography and magnetic resonance imaging to explore neurophysiological function and brain structures.

RESULTS

We analysed the clinical, psychological, neuroradiological and neurophysiological features of 12 yet-unpublished individuals affected by this rare genetic anomaly, focusing specifically on the last two aspects. Several structural abnormalities of the central nervous system were detected, like ventriculomegaly, hypotrophic cerebellum, hypotrophic corpus callosum and hypoplastic temporal lobes. Although only one of 12 individuals suffered from seizures during childhood, three others had abnormal electroencephalography findings prominent in the anterior brain regions, without any visible seizures to date.

CONCLUSION

Taken together, we enlarged the yet-underrepresented cohort in the literature of patients affected by 7q11.23 microduplication syndrome and shed further light on neuroradiological and neurophysiological aspects of this rare genetic syndrome.

A method for determining haploid and triploid genotypes and their association with vascular phenotypes in Williams syndrome and 7q11.23 duplication syndrome

Background

Williams syndrome ([WS], 7q11.23 hemideletion) and 7q11.23 duplication syndrome (Dup7) show contrasting syndromic symptoms. However, within each group there is considerable interindividual variability in the degree to which these phenotypes are expressed. Though software exists to identify areas of copy number variation (CNV) from commonly-available SNP-chip data, this software does not provide non-diploid genotypes in CNV regions. Here, we describe a method for identifying haploid and triploid genotypes in CNV regions, and then, as a proof-of-concept for applying this information to explain clinical variability, we test for genotype-phenotype associations.

Methods

Blood samples for 25 individuals with WS and 13 individuals with Dup7 were genotyped with Illumina-HumanOmni5M SNP-chips. PennCNV and in-house code were used to make genotype calls for each SNP in the 7q11.23 locus. We tested for association between the presence of aortic arteriopathy and genotypes of the remaining (haploid in WS) or duplicated (triploid in Dup7) alleles.

Results

Haploid calls in the 7q11.23 region were made for 99.0% of SNPs in the WS group, and triploid calls for 98.8% of SNPs in those with Dup7. The G allele of SNP rs2528795 in the ELN gene was associated with aortic stenosis in WS participants (p < 0.0049) while the A allele of the same SNP was associated with aortic dilation in Dup7.

Conclusions

Commonly available SNP-chip information can be used to make haploid and triploid calls in individuals with CNVs and then to relate variability in specific genes to variability in syndromic phenotypes, as demonstrated here using aortic arteriopathy. This work sets the stage for similar genotype-phenotype analyses in CNVs where phenotypes may be more complex and/or where there is less information about genetic mechanisms.

Electronic supplementary material

The online version of this article (10.1186/s12881-018-0563-3) contains supplementary material, which is available to authorized users.

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.

Distal 7q11.23 Duplication, an Emerging Microduplication Syndrome: A Case Report and Further Characterisation

Chromosome 7q11.23 duplication syndrome is a well-recognised syndrome which involves the duplication of the same genes located in the Williams-Beuren critical region. However, in 2010, 4 patients were reported with a microduplication only in the HIP1 and YWHAG genes. We refer to this as a distal 7q11.23 duplication (dup7q11.23D). Here, we report the fifth de novo patient with dup7q11.23D, whose symptoms may be explained by YWHAG overexpression as was demonstrated recently in mice and obese patients. Finally, further studies will be necessary to delineate this emerging microduplication syndrome.

The 7q11.23 Microduplication Syndrome: A Clinical Report with Review of Literature

We report a 14-year-old adolescent girl with selective mutism (SM) and a 7q11.23 microduplication detected by chromosomal microarray (CMA) analysis and reviewed the literature from 18 published clinical reports. Our patient had specific phobias, SM, extreme anxiety, obesity, cutis marmorata, and a round appearing face with a short neck and over folded ears. We reviewed the published clinical, cognitive, behavioral, and cytogenetic findings grouped by speech and language delay, growth and development, craniofacial, clinical, and behavior and cognitive features due to the 7q11.23 microduplication. This microduplication syndrome is characterized by speech delay (91%), social anxiety (42%), attention deficit hyperactivity disorder (ADHD, 37%), autism spectrum disorder (29%), and separation anxiety (13%). Other findings include abnormal brain imaging (80%), congenital heart and vascular defects (54%), and mild intellectual disability (38%). We then compared the phenotype with Williams-Beuren syndrome (WBS) which is due to a deletion of the same chromosome region. Both syndromes have abnormal brain imaging, hypotonia, delayed motor development, joint laxity, mild intellectual disability, ADHD, autism, and poor visuospatial skills but opposite or dissimilar findings regarding speech and behavioral patterns, cardiovascular problems, and social interaction. Those with WBS are prone to have hyperverbal speech, lack of stranger anxiety, and supravalvular aortic stenosis while those with the 7q11.23 microduplication have speech delay, SM, social anxiety, and are prone to aortic dilatation.

7q11.23 Duplication syndrome: Physical characteristics and natural history

In order to describe the physical characteristics, medical complications, and natural history of classic 7q11.23 duplication syndrome [hereafter Dup7 (MIM 609757)], reciprocal duplication of the region deleted in Williams syndrome [hereafter WS (MIM 194050)], we systematically evaluated 53 individuals aged 1.25-21.25 years and 11 affected adult relatives identified in cascade testing. In this series, 27% of probands with Dup7 had an affected parent. Seven of the 26 de novo duplications that were examined for inversions were inverted; in all seven cases one of the parents had the common inversion polymorphism of the WS region. We documented the craniofacial features of Dup7: brachycephaly, broad forehead, straight eyebrows, broad nasal tip, low insertion of the columella, short philtrum, thin upper lip, minor ear anomalies, and facial asymmetry. Approximately 30% of newborns and 50% of older children and adults had macrocephaly. Abnormalities were noted on neurological examination in 88.7% of children, while 81.6% of MRI studies showed structural abnormalities such as decreased cerebral white matter volume, cerebellar vermis hypoplasia, and ventriculomegaly. Signs of cerebellar dysfunction were found in 62.3%, hypotonia in 58.5%, Developmental Coordination Disorder in 74.2%, and Speech Sound Disorder in 82.6%. Behavior problems included anxiety disorders, ADHD, and oppositional disorders. Medical problems included seizures, 19%; growth hormone deficiency, 9.4%; patent ductus arteriosus, 15%; aortic dilation, 46.2%; chronic constipation, 66%; and structural renal anomalies, 18%. We compare these results to the WS phenotype and offer initial recommendations for medical evaluation and surveillance of individuals who have Dup7.

Aortic dilation, genetic testing, and associated diagnoses

PURPOSE

The aims of this study were to determine the genetic diagnoses most frequently associated with aortic dilation in a large population and to describe the results of genetic testing in the same.

METHODS

A retrospective review of records from patients with known aortic dilation identified through an echocardiogram database was performed. During the study period, different chromosomal microarray platforms and molecular diagnostic techniques were used.

RESULTS

A total of 715 patients (mean age, 9.7 years; 67% male) met study inclusion criteria. The overall frequency of underlying presumptive or confirmed genetic diagnoses was 17% (125/715). Molecular evaluation for possible underlying aortopathy-related disorders was performed in 9% of patients (66/715). Next-generation sequencing panels were performed in 16 patients, and pathogenic abnormalities were detected in 4 (25%). Microarrays were conducted in 10% of patients (72/715), with a total of 23 pathogenic copy-number variants identified in 19 patients (26%). Marfan syndrome was the most frequently recognized genetic disorder associated with aortic dilation, but other cytogenetic abnormalities and associated diagnoses also were identified.

CONCLUSION

The differential diagnosis in patients with aortic dilation is broad and includes many conditions outside the common connective tissue disorder spectrum. A genetics evaluation should be considered to assist in the diagnostic evaluation.Genet Med 18 4, 356-363.

Familial 7q11.23 duplication with variable phenotype

Chromosomal microdeletions and microduplications are known to cause variable clinical features ranging from apparently normal phenotype to intellectual disability, multiple congenital anomalies, and/or other variable clinical features. 7q11.23 region deletion is the cause for Williams-Beuren syndrome and duplication of same region 7q11.23 causes distinguishable clinical phenotype. Familial inheritance is known for both microdeletion and microduplication of 7q11.23 region. Here, we report a patient of paternally inherited 7q11.23 microduplication with developmental delay, macrocephaly, and structural brain malformations.

Children with 7q11.23 duplication syndrome: psychological characteristics

To begin to delineate the psychological characteristics associated with classic 7q11.23 duplication syndrome (duplication of the classic Williams syndrome region; hereafter classic Dup7), we tested 63 children with classic Dup7 aged 4-17 years. Sixteen toddlers aged 18-45 months with classic Dup7 and 12 adults identified by cascade testing also were assessed. For the child group, median General Conceptual Ability (similar to IQ) on the Differential Ability Scales-II was 85.0 (low average), with a range from severe disability to high average ability. Median reading and mathematics achievement standard scores were at the low average to average level, with a range from severe impairment to high average or superior ability. Adaptive behavior was considerably more limited; median Scales of Independent Behavior-Revised Broad Independence standard score was 62.0 (mild impairment), with a range from severe adaptive impairment to average adaptive ability. Anxiety disorders were common, with 50.0% of children diagnosed with Social Phobia, 29.0% with Selective Mutism, 12.9% with Separation Anxiety Disorder, and 53.2% with Specific Phobia. In addition, 35.5% were diagnosed with Attention Deficit/Hyperactivity Disorder and 24.2% with Oppositional Defiant Disorder or Disruptive Behavior Disorder-Not Otherwise Specified. 33.3% of the children screened positive for a possible Autism Spectrum Disorder and 82.3% were diagnosed with Speech Sound Disorder. We compare these findings to previously reported results for children with Williams syndrome and argue that genotype/phenotype studies involving the Williams syndrome region offer important opportunities to understand the contribution of genes in this region to common disorders affecting the general population.

Williams-Beuren syndrome associated with single kidney and nephrocalcinosis: a case report

Williams-Beuren syndrome is a rare neurodevelopmental disorder, characterized by congenital heart defects, abnormal facial features, mental retardation with specific cognitive and behavioral profile, growth hormone deficiency, renal and skeletal anomalies, inguinal hernia, infantile hypercalcaemia. We report a case with Williams-Beuren syndrome associated with a single kidney and nephrocalcinosis complicated by hypercalcaemia. A male infant, aged 20 months presented growth retardation associated with a psychomotor impairment, dysmorphic features and nephrocalcinosis. He had also hypercalciuria and hypercalcemia. Echocardiography was normal. DMSA renal scintigraphy showed a single functioning kidney. The FISH generated one ELN signal in 20 metaphases read and found the presence of ELN deletion, with compatible Williams-Beuren syndrome.

Critical care of patients with paediatric valvar cardiac disease

Valvar cardiac disease accounts for a large percentage of heart lesions in the paediatric population. There are a variety of congenital and acquired valvar lesions produced by different mechanisms that produce unique physiologies. With the development of more advanced cardiac interventional procedures and congenital cardiac surgery techniques, most of these lesions can be repaired in a single or multi-stage approach. Given the potential for significant symptomatology before intervention, it is imperative to review the critical care management of paediatric valvar heart disease. The purpose of this article is to provide an overview of the current critical care management of valvar cardiac disease. We approach each cardiac valve individually in order to review the pathophysiology caused by valve dysfunction (obstruction and incompetence) and elaborate on the most frequent diagnoses, specific cardiac physiology, potential for other organ system associations, and perioperative management.