Prevalence of Beckwith-Wiedemann syndrome in North West of Italy

Cognitive, Social, and Emotional-Behavioral Outcomes in Children and Adolescents With Beckwith-Wiedemann Syndrome

Although Beckwith-Wiedemann syndrome spectrum (BWSp) is not usually associated with intellectual disability, recent evidences calls for further investigation of cognitive development and academic skills in children with BWSp. Moreover, research has documented social difficulties and emotional-behavioral problems associated with BWSp. Nevertheless, a full characterization of socio-emotional development in BWSp is still lacking. In the current study, cognitive and socio-emotional development was assessed in 29 children with BWSp aged 5-18 years, using a test of nonverbal intelligence, a neuropsychological battery covering multiple domains, academic skills tests, and questionnaires evaluating autistic traits and emotional-behavioral problems. As expected, most participants showed adequate performance in cognitive tests. However, the findings also highlighted greater difficulties in language than visuospatial processing, strengths in social perception, as well as slowness in reading and mental calculation. The assessment of emotional-behavioral difficulties indicated a prevalent phenotype characterized by increased anxiety, low self-esteem, social withdrawal and a tendency to control externalizing reactions, but no associations with autistic traits, cognitive outcomes, and the clinical score proposed by the recent Consensus statement. Increased social perception and internalization problems likely result from coping strategies with social and care-related stress. Overall, the findings of this study inform clinical management and genetic counseling for children and adolescents with BWSp.

A rare case of extremely low birth weight infant with Beckwith-Wiedemann syndrome

INTRODUCTION

Beckwith-Wiedemann syndrome (BWS) manifests distinctive features, such as macroglossia, overgrowth, and abdominal wall defects. In this report, we describe a case of BWS in an extremely low birth weight infant diagnosed at three months after birth because of the intensive care for low birth weight.

PRESENTATION OF CASE

A female infant was delivered at 24 weeks and 6 days of gestation with a weight of 845 g. After birth, significant small intestinal intra-umbilical prolapse was observed, and abdominal wall closure using a sutureless method was performed on day zero. Careful neonatal management was performed; however, an episode of bloody stools led to a diagnosis of intestinal volvulus due to intestinal malrotation. At 119 days of age, the Ladd procedure was performed. Notably, during anaesthesia induction, features suggestive of BWS were observed, leading to its diagnosis.

DISCUSSION

Early diagnosis of BWS is vital because of its association with tumors. However, because she was an extremely low birth weight infant who required oral intubation and supine management for respiratory control, nevus flammeus and macroglossia were not observed. Therefore, BWS was not diagnosed for approximately three months after birth. It is important to recognize that omphalocele in extremely low birth weight infants is a risk factor for delayed diagnosis of BWS.

CONCLUSION

Timely diagnosis of BWS is critical because of its association with tumors and varied clinical presentations. Early screening, especially for tumors, and awareness among surgical practitioners can aid in timely interventions and improved patient outcomes.

Development of disease-specific growth charts for Korean children with Beckwith-Wiedemann syndrome

Beckwith-Wiedemann syndrome (BWS) is an epigenetic overgrowth syndrome. Despite its distinctive growth pattern, the detailed growth trajectories of children with BWS remain largely unknown. We retrospectively analyzed 413 anthropometric measurements over an average of 4.4 years of follow-up in 51 children with BWS. We constructed sex-specific percentile curves for height, weight, and head circumference using a generalized additive model for location, scale, and shape. Males with BWS exhibited greater height at all ages evaluated, weight before the age of 10, and head circumference before the age of 9 than those of the general population. Females with BWS showed greater height before the age of 7, weight before the age of 4.5, and head circumference before the age of 7 than those of the general population. At the latest follow-up visit at a mean 8.4 years of age, bone age was significantly higher than chronological age. Compared to paternal uniparental disomy (pUPD), males with imprinting center region 2-loss of methylation (IC2-LOM) had higher standard deviation score (SDS) for height and weight, while females with IC2-LOM showed larger SDS for head circumference. These disease-specific growth charts can serve as valuable tools for clinical monitoring of children with BWS.

Effective Collaboration in the Surgical Management of Macroglossia in Beckwith-Wiedemann Syndrome

Beckwith-Wiedemann syndrome (BWS) is a complex congenital overgrowth disorder necessitating a multidisciplinary approach for effective management. A 5-year-old Saudi girl with BWS received comprehensive care involving various specialists, including a plastic surgeon who performed a keyhole technique tongue reduction to address macroglossia. The intervention resulted in significant improvements in speech and quality of life, with no postoperative complications. Intensive speech therapy further enhanced speech development. This case report emphasizes the importance of a multidisciplinary approach and the critical role of the plastic surgeon in managing BWS patients with macroglossia to achieve optimal outcomes.

The counterpart congenital overgrowth syndromes Beckwith-Wiedemann Syndrome in human and large offspring syndrome in bovine involve alterations in DNA methylation, transcription, and chromatin configuration

Beckwith-Wiedemann Syndrome (BWS, OMIM #130650) is a congenital epigenetic disorder in humans which affects approximately 1 in 10,340 children. The incidence is likely an underestimation as the condition is usually recognized based on observable phenotypes at birth. BWS children have up to a 28% risk of developing tumors and currently, only 80% of patients can be corroborated molecularly (epimutations/variants). It is unknown how the subtypes of this condition are molecularly similar/dissimilar globally, therefore there is a need to deeply characterize the syndrome at the molecular level. Here we characterize the methylome, transcriptome and chromatin configuration of 18 BWS individuals together with the animal model of the condition, the bovine large offspring syndrome (LOS). Sex specific comparisons are performed for a subset of the BWS patients and LOS. Given that this epigenetic overgrowth syndrome has been characterized as a loss-of-imprinting condition, parental allele-specific comparisons were performed using the bovine animal model. In general, the differentially methylated regions (DMRs) detected in BWS and LOS showed significant enrichment for CTCF binding sites. Altered chromosome compartments in BWS and LOS were positively correlated with gene expression changes, and the promoters of differentially expressed genes showed significant enrichment for DMRs, differential topologically associating domains, and differential A/B compartments in some comparisons of BWS subtypes and LOS. We show shared regions of dysregulation between BWS and LOS, including several HOX gene clusters, and also demonstrate that altered DNA methylation differs between the clinically epigenetically identified BWS patients and those identified as having DNA variants (i.e. CDKN1C microdeletion). Lastly, we highlight additional genes and genomic regions that have the potential to serve as targets for biomarker development to improve current molecular methodologies. In summary, our results suggest that genome-wide alternation of chromosome architecture, which is partially caused by DNA methylation changes, also contribute to the development of BWS and LOS.

Psychiatric Disorder in a Patient With Beckwith-Wiedemann Syndrome: A Case Report

Patients with Beckwith-Wiedemann syndrome (BWS) often suffer from pheochromocytoma and hypoglycaemia and are vulnerable to disorders associated with the hypothalamic-pituitary-adrenal axis (HPA), such as major depressive disorder, generalised anxiety disorder, borderline personality disorder, etc. Features of pheochromocytoma even overlap with features of anxiety disorders, panic disorders, etc. These patients undergo multiple major surgeries under general anaesthesia at a very young age due to recurrent tumours that can affect their behavioural and emotional development. Depriving them of much-needed medical and emotional support negatively impacts their physical and psychological well-being. In this case report, we present the case of a 23-year-old woman with Beckwith-Wiedemann syndrome (BWS) who underwent major surgeries such as partial pancreatectomy, adrenalectomy, osteotomy, and paraganglioma resection at an early age. She was neglected by her parents and spent her childhood in an abusive environment. All these factors could have increased her vulnerability to mental health problems. She was diagnosed with borderline personality disorder, major depressive disorder, unspecified trauma, stressor-related disorders, cannabis use disorder, and cannabis-induced psychotic symptoms. This report emphasises the role of medical comorbidity in a patient presenting with borderline personality disorder.

[Preterm with Macroglossia and Persistent Hypoglycemia - Beckwith-Wiedemann Syndrome]

Beckwith-Wiedemann syndrome (BWS) is a genetic disease with phenotypic variability and the following signs: macroglossia, asymmetry, lateralised overgrowth, overgrowth of the internal organs, abdominal wall defects, neonatal hypoglycemia and increased risk of embryonic tumours. The prevalence is reported as being between 1 in 10,000 and 1 in 21,000 live births. The disease is caused by molecular changes in gene clusters on the short arm of chromosome 11 region P15.5. We present the case of a female, born preterm at 32 0/7 weeks. A UPD(11)pat-mutation was diagnosed postnatally. The particular feature of her case was an early tongue reduction surgery which was necessary because of drinking and breathing difficulties. Long-lasting hypoglycemia was difficult to treat.

Syndromic forms of congenital hyperinsulinism

Congenital hyperinsulinism (CHI), also called hyperinsulinemic hypoglycemia (HH), is a very heterogeneous condition and represents the most common cause of severe and persistent hypoglycemia in infancy and childhood. The majority of cases in which a genetic cause can be identified have monogenic defects affecting pancreatic β-cells and their glucose-sensing system that regulates insulin secretion. However, CHI/HH has also been observed in a variety of syndromic disorders. The major categories of syndromes that have been found to be associated with CHI include overgrowth syndromes (e.g. Beckwith-Wiedemann and Sotos syndromes), chromosomal and monogenic developmental syndromes with postnatal growth failure (e.g. Turner, Kabuki, and Costello syndromes), congenital disorders of glycosylation, and syndromic channelopathies (e.g. Timothy syndrome). This article reviews syndromic conditions that have been asserted by the literature to be associated with CHI. We assess the evidence of the association, as well as the prevalence of CHI, its possible pathophysiology and its natural course in the respective conditions. In many of the CHI-associated syndromic conditions, the mechanism of dysregulation of glucose-sensing and insulin secretion is not completely understood and not directly related to known CHI genes. Moreover, in most of those syndromes the association seems to be inconsistent and the metabolic disturbance is transient. However, since neonatal hypoglycemia is an early sign of possible compromise in the newborn, which requires immediate diagnostic efforts and intervention, this symptom may be the first to bring a patient to medical attention. As a consequence, HH in a newborn or infant with associated congenital anomalies or additional medical issues remains a differential diagnostic challenge and may require a broad genetic workup.

Oral Health-Related Quality of Life among Children and Adolescents with Beckwith–Wiedemann Syndrome in Northern Italy

Due to associated maxillofacial growth anomalies and the impairment of oral functions, macroglossia may negatively impact the oral health-related quality of life (OHRQoL) of people with Beckwith–Wiedemann syndrome (BWS). Therefore, the aim of this cross-sectional study was to determine the OHRQoL of Italian children and adolescents with BWS compared to healthy peers and to identify which symptoms related to macroglossia had the highest impact. A total of 48 patients with BWS and 48 age- and gender-matched controls completed the Italian version of OHIP-14 and a questionnaire on functional, oral and aesthetic outcomes. Parents of patients with BWS who had undergone tongue reduction surgery (TRS) answered additional questions related to surgery. The BWS group scored higher than controls on the total OHIP-14 and on the dimensions of oral function (p: 0.036) and psychosocial impact (p: 0.002), indicating a reduced OHRQoL. Neither gender nor age had an impact on OHRQoL. Scores were worse in children and adolescents treated with TRS, as most of them still had open bite malocclusion and speech difficulties. The OHRQoL of children and adolescents affected by BWS is worse than that of their healthy peers in spite of the surgical treatment of macroglossia.

Clinical and molecular characterization of patients affected by Beckwith-Wiedemann spectrum conceived through assisted reproduction techniques

The prevalence of Beckwith–Wiedemann spectrum (BWSp) is tenfold increased in children conceived through assisted reproductive techniques (ART). More than 90% of ART‐BWSp patients reported so far display imprinting center 2 loss‐of‐methylations (IC2‐LoM), versus 50% of naturally conceived BWSp patients. We describe a cohort of 74 ART‐BWSp patients comparing their features with a cohort of naturally conceived BWSp patients, with the ART‐BWSp patients previously described in literature, and with the general population of children born from ART. We found that the distribution of UPD(11)pat was not significantly different in ART and naturally conceived patients. We observed 68.9% of IC2‐LoM and 16.2% of mosaic UPD(11)pat in our ART cohort, that strongly differ from the figure reported in other cohorts so far. Since UPD(11)pat likely results from post‐fertilization recombination events, our findings allows to hypothesize that more complex molecular mechanisms, besides methylation disturbances, may underlie BWSp increased risk in ART pregnancies. Moreover, comparing the clinical features of ART and non‐ART BWSp patients, we found that ART‐BWSp patients might have a milder phenotype. Finally, our data show a progressive increase in the prevalence of BWSp over time, paralleling that of ART usage in the last decades.

Proposal for Practical Approach in Prenatal Diagnosis of Beckwith–Wiedemann Syndrome and Review of the Literature

Background: Beckwith–Wiedemann syndrome (BWS) is a phenotypically and genetically heterogeneous disorder associated with epigenetic/genetic aberrations on chromosome 11p15.4p15.5. There is no consensus criterion for prenatal diagnosis of BWS. Methods: Three BWS patients with their clinical histories, prenatal ultrasonographic features, and results of molecular diagnosis were presented. Likewise, by incorporating the findings of our cases and literature review, the phenotypic spectrum and genotype–phenotype correlations of fetal BWS were summarized, and a practical approach in prenatal diagnosis of BWS was proposed. Results: A total of 166 BWS cases with prenatal features were included for analysis. Common fetal features include abdominal wall defects (42.8%), polyhydramnios (33.1%), and macrosomia (32.5%). Molecular pathologies include methylation changes in imprinting control region 1 and 2 (ICR1 and ICR2), paternal uniparental disomy of chromosome 11p15.5, copy number change involving 11p15, etc. Some genotype–phenotype correlations were observed. However, the broad phenotypic spectrum but limited features manifested by affected fetuses rendering ultrasonographic diagnosis not easy. Conclusions: Molecular tests are used for prenatal diagnosis of BWS suspected by ultrasonography. Methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) is recommended as the first-line molecular tool because it simultaneously detects ICR1/ICR2 methylation statuses and copy numbers that solve the majority of clinical cases in the prenatal scenario.

Epimutation in inherited metabolic disorders: the influence of aberrant transcription in adjacent genes

Epigenetic diseases can be produced by a stable alteration, called an epimutation, in DNA methylation, in which epigenome alterations are directly involved in the underlying molecular mechanisms of the disease. This review focuses on the epigenetics of two inherited metabolic diseases, epi-cblC, an inherited metabolic disorder of cobalamin (vitamin B₁₂) metabolism, and alpha-thalassemia type α-ZF, an inherited disorder of α2-globin synthesis, with a particular interest in the role of aberrant antisense transcription of flanking genes in the generation of epimutations in CpG islands of gene promoters. In both disorders, the epimutation is triggered by an aberrant antisense transcription through the promoter, which produces an H3K36me3 histone mark involved in the recruitment of DNA methyltransferases. It results from diverse genetic alterations. In alpha-thalassemia type α-ZF, a deletion removes HBA1 and HBQ1 genes and juxtaposes the antisense LUC7L gene to the HBA2 gene. In epi-cblC, the epimutation in the MMACHC promoter is produced by mutations in the antisense flanking gene PRDX1, which induces a prolonged antisense transcription through the MMACHC promoter. The presence of the epimutation in sperm, its transgenerational inheritance via the mutated PRDX1, and the high expression of PRDX1 in spermatogonia but its nearly undetectable transcription in spermatids and spermatocytes, suggest that the epimutation could be maintained during germline reprogramming and despite removal of aberrant transcription. The epivariation seen in the MMACHC promoter (0.95 × 10^-3) is highly frequent compared to epivariations affecting other genes of the Online Catalog of Human Genes and Genetic Disorders in an epigenome-wide dataset of 23,116 individuals. This and the comparison of epigrams of two monozygotic twins suggest that the aberrant transcription could also be influenced by post-zygotic environmental exposures.

Maxillo-Facial Morphology in Beckwith-Wiedemann Syndrome: A Preliminary Study on (epi)Genotype-Phenotype Association in Caucasians

Beckwith–Wiedemann syndrome (BWS) is a congenital overgrowth disorder caused by various (epi)genetic alterations affecting the expression of genes on chromosome 11p15. Cardinal features include abdominal wall defects, macroglossia, and cancer predisposition. Several (epi)genotype–phenotype associations were described so far, but specific studies on the evolution over time of maxillo-facial phenotype in the molecular subtypes still are scanty. The aim of this cross-sectional study was to associate maxillo-facial morphology and growth pattern with genoype in 25 Caucasian children with BWS and macroglossia. Twelve patients experienced a loss of metilation at imprinting center 2 (IC2-LoM), five had mosaic paternal uniparental isodisomy of chromosome 11 (UPD(11)pat), and eight were negative. A more marked tongue enlargement was detected in patients with IC2-LoM and negative genotype, while UPD(11)pat children showed mild macroglossia (p = 0.048). A cluster analysis did not demonstrate any specific relationship between (epi)genotype and maxillo-facial phenotype, but separated BWS patients based on their cephalometric characteristics. Children with IC2-LoM or negative genotype displayed hyperdivergence values > 30°, clockwise growth tendency, and skeletal class II into the same cluster. They had a negative prognostic score. These preliminary data suggest the need for developing individualized protocols for early monitoring of the craniofacial growth in such patients.

Glioblastoma in Beckwith-Wiedemann syndrome: first case report and review of potential pathomechanisms

Beckwith-Wiedemann syndrome (BWS) is a rare congenital overgrowth syndrome associated with certain childhood tumours. We present the case of a 36-year-old lady with BWS who developed a left frontoinsular secondary glioblastoma. This is the first case report in the literature of glioblastoma associated with BWS. We explore similarities in the molecular pathomechanisms of BWS and glioblastoma.

Lateralized and Segmental Overgrowth in Children

Congenital disorders of lateralized or segmental overgrowth (LO) are heterogeneous conditions with increased tissue growth in a body region. LO can affect every region, be localized or extensive, involve one or several embryonic tissues, showing variable severity, from mild forms with minor body asymmetry to severe ones with progressive tissue growth and related relevant complications. Recently, next-generation sequencing approaches have increased the knowledge on the molecular defects in LO, allowing classifying them based on the deranged cellular signaling pathway. LO is caused by either genetic or epigenetic somatic anomalies affecting cell proliferation. Most LOs are classifiable in the Beckwith-Wiedemann spectrum (BWSp), PI3KCA/AKT-related overgrowth spectrum (PROS/AROS), mosaic RASopathies, PTEN Hamartoma Tumor Syndrome, mosaic activating variants in angiogenesis pathways, and isolated LO (ILO). These disorders overlap over common phenotypes, making their appraisal and distinction challenging. The latter is crucial, as specific management strategies are key: some LO is associated with increased cancer risk making imperative tumor screening since childhood. Interestingly, some LO shares molecular mechanisms with cancer: recent advances in tumor biological pathway druggability and growth downregulation offer new avenues for the treatment of the most severe and complicated LO.

The Role of Long Non-coding RNAs in Human Imprinting Disorders: Prospective Therapeutic Targets

Genomic imprinting is a term used for an intergenerational epigenetic inheritance and involves a subset of genes expressed in a parent-of-origin-dependent way. Imprinted genes are expressed preferentially from either the paternally or maternally inherited allele. Long non-coding RNAs play essential roles in regulating this allele-specific expression. In several well-studied imprinting clusters, long non-coding RNAs have been found to be essential in regulating temporal- and spatial-specific establishment and maintenance of imprinting patterns. Furthermore, recent insights into the epigenetic pathological mechanisms underlying human genomic imprinting disorders suggest that allele-specific expressed imprinted long non-coding RNAs serve as an upstream regulator of the expression of other protein-coding or non-coding imprinted genes in the same cluster. Aberrantly expressed long non-coding RNAs result in bi-allelic expression or silencing of neighboring imprinted genes. Here, we review the emerging roles of long non-coding RNAs in regulating the expression of imprinted genes, especially in human imprinting disorders, and discuss three strategies targeting the central long non-coding RNA UBE3A-ATS for the purpose of developing therapies for the imprinting disorders Prader-Willi syndrome and Angelman syndrome. In summary, a better understanding of long non-coding RNA-related mechanisms is key to the development of potential therapeutic targets for human imprinting disorders.

Epigenetic mosaicism and cell burden in Beckwith-Wiedemann Syndrome due to loss of methylation at imprinting control region 2

Beckwith–Wiedemann syndrome (BWS) is a rare overgrowth disorder caused by epigenetic alterations on Chromosome 11p15.5. Most molecular changes are sporadic and are thought to occur in a mosaic pattern. Thereby, the distribution of affected cells differs between tissues for each individual, which can complicate genotype–phenotype correlations. In two of the BWS molecular subtypes, tissue mosaicism has been demonstrated; however, mosaicism has not been specifically studied in the most common cause of BWS, loss of methylation (LOM) at KCNQ1OT1:TSS differentially methylated region (DMR) imprinting center 2 (IC2) LOM. The increased prevalence of twinning associated with the IC2 LOM subtype and the discordant phenotypes between the twins previously led to the proposal of diffused epigenetic mosaicism, leading to asymmetric distribution of affected cells during embryonic development. In this study, we evaluated the level of methylation detected in 64 samples collected from 30 individuals with IC2 LOM. We demonstrate that the IC2 LOM defect can occur in mosaic and nonmosaic patterns, and tissues from the same individual can show variable patterns, which suggests that this asymmetric distribution occurs during development. We further suggest that the clinical phenotype in individuals with BWS IC2 LOM is correlated with the epigenetic burden of affected cells in each tissue type. This series is the first report to demonstrate tissue mosaicism within the IC2 LOM epigenotype, and consideration of this mosaicism is necessary to understanding the pathogenesis of BWS.

Quantitative DNA Methylation Analysis and Epigenotype-Phenotype Correlations in Taiwanese Patients with Beckwith-Wiedemann Syndrome

Background: Beckwith-Wiedemann syndrome (BWS; OMIM 130650) is a rare overgrowth syndrome with tumor predisposition resulting from the abnormal expression or function of imprinted genes of the chromosome 11p15.5 imprinting gene cluster. The aim of this study was to identify the epigenotype-phenotype correlations of these patients using quantitative DNA methylation analysis. Methods: One hundred and four subjects with clinically suspected BWS were enrolled in this study. All of the subjects had been referred for diagnostic testing which was conducted using methylation profiling of H19-associated imprinting center (IC) 1 and KCNQ1OT1-associated IC2 in high-resolution melting analysis and methylation quantification with the MassARRAY assay. Correlations between the quantitative DNA methylation status and clinical manifestations of the enrolled subjects were analyzed. Results: Among the 104 subjects, 19 had IC2 hypomethylation, 2 had IC1 hypermethylation, and 10 had paternal uniparental disomy (pUPD). The subjects with IC2 hypomethylation were characterized by significantly more macroglossia but less hemihypertrophy compared to the subjects with pUPD (p < 0.05). For 19 subjects with IC2 hypomethylation, the IC2 methylation level was significantly different (p < 0.05) between the subjects with and without features including macroglossia (IC2 methylation level: 11.1% vs. 30.0%) and prenatal or postnatal overgrowth (8.5% vs. 16.9%). The IC2 methylation level was negatively correlated with birth weight z score (p < 0.01, n = 19) and birth height z score (p < 0.05, n = 13). For 36 subjects with clinically diagnosed BWS, the IC2 methylation level was negatively correlated with the BWS score (r = −0.592, p < 0.01). The IC1 methylation level showed the tendency of positive correlation with the BWS score without statistical significance (r = 0.137, p > 0.05). Conclusions: Lower IC2 methylation and higher IC1 methylation levels were associated with greater disease severity in the subjects with clinically diagnosed BWS. Quantitative DNA methylation analysis using the MassARRAY assay could improve the detection of epigenotype-phenotype correlations, which could further promote better genetic counseling and medical care for these patients.

Beckwith-Wiedemann syndrome: Clinical, histopathological and molecular study of two Tunisian patients and review of literature

Background

Beckwith–Wiedemann syndrome (BWS) is a rare overgrowth syndrome characterized by congenital malformations and predisposition to embryonic tumors. Loss of methylation of imprinting center 2 (IC2) is the most frequent alteration and rarely associated with tumors compared to paternal uniparental disomy of chromosome 11 (UPD(11)pat) and gain of methylation of imprinting center 1.

Methods

Our study aimed to describe the clinical, histopathological and genetic characteristics of two patients and establish genotype‐phenotype correlations. The clinical diagnosis was based on the criteria defined by the international expert consensus of BWS. Molecular study of 11p15.5 methylation status was assessed using methylation‐specific‐multiplex ligation probe amplification (MS‐MLPA).

Results

Patients were aged 12 months and 3 months and fulfilled the clinical score of BWS. MS‐MLPA showed molecular alterations consisting of loss of methylation in IC2 (IC2‐LOM) at the maternal allele for one patient and a mosaic UPD(11)pat for the second patient in whom follow‐up at 6months revealed adrenocortical carcinoma (ACC) with low grade of malignancy. Molecular subtypes guide the follow‐up and tumor surveillance, our major concern.

Conclusion

We have to take into account the psychological impact of a possible tumor whatever the underlying mechanism is. Nevertheless, the tumor risk remains high for UPD(11)pat. Our study extended the phenotype of BWS with absence of macrosomia in Tunisian patients, contrasting with literature, and added a supplementary case of ACC in the tumor spectrum of BWS patients with UPD(11)pat.

The role of CTCF in the organization of the centromeric 11p15 imprinted domain interactome

DNA methylation, chromatin-binding proteins, and DNA looping are common components regulating genomic imprinting which leads to parent-specific monoallelic gene expression. Loss of methylation (LOM) at the human imprinting center 2 (IC2) on chromosome 11p15 is the most common cause of the imprinting overgrowth disorder Beckwith-Wiedemann Syndrome (BWS). Here, we report a familial transmission of a 7.6 kB deletion that ablates the core promoter of KCNQ1. This structural alteration leads to IC2 LOM and causes recurrent BWS. We find that occupancy of the chromatin organizer CTCF is disrupted proximal to the deletion, which causes chromatin architecture changes both in cis and in trans. We also profile the chromatin architecture of IC2 in patients with sporadic BWS caused by isolated LOM to identify conserved features of IC2 regulatory disruption. A strong interaction between CTCF sites around KCNQ1 and CDKN1C likely drive their expression on the maternal allele, while a weaker interaction involving the imprinting control region element may impede this connection and mediate gene silencing on the paternal allele. We present an imprinting model in which KCNQ1 transcription is necessary for appropriate CTCF binding and a novel chromatin conformation to drive allele-specific gene expression.

A case of unilateral sectoral iris heterochromia in an infant with Beckwith-Wiedemann syndrome

Purpose

To report a case of unilateral sectoral iris heterochromia in an infant with Beckwith-Wiedemann syndrome (BWS).

Observations

An 8-month-old girl known case of BWS, due to hypomethylation of the DMR2 (KCNQ1OT1) on chromosome 11p15.5, with features of macroglossia, neonatal hypoglycaemia and an unusual finding of partial iris hypopegmentaion in her left eye.

Conclusions

This is the first reported case of iris heterochromia in a BWS patient. Further studies are needed to support the association between eye findings and BWS related genetic defects.

Beckwith-Wiedemann syndrome with macroglossia as the most significant manifestation: A case report

Beckwith-Wiedemann syndrome is a complex multisystem disorder that requires collaboration of medical and dental teamfor its diagnosis and management. We present a dental overview and an update of the clinical and molecular diagnoses of Beckwith-Wiedemann syndrome and its management with emphasis on macroglossia.

Clinical and Cytogenomic Characterization of De Novo 11p14.3-p15.5 Duplication Associated with 18q23 Deletion in an Egyptian Female Infant

Paternal microduplication of 11p14.3-p15.5 causes the clinical manifestations of Beckwith-Wiedemann syndrome (BWS), while microdeletion of 18q23-ter is clinically characterized by short stature, congenital malformations, and developmental delay. We describe a 15-month-old girl presenting with protruding tongue, dysmorphic facial features, moderate developmental delay, umbilical hernia, hypotonia, mild-to-moderate pulmonary hypertension, small patent ductus arteriosus, and mild ventricular septal hypertrophy. Brain magnetic resonance imaging showed mild atrophic changes. Chromosomal analysis revealed 46, XX, add(18)(q23). Fluorescence in situ hybridization using subtelomere 18q and whole chromosome painting 18 showed subtelomere deletion in 18q, and the add segment was not derived from chromosome 18. Microarray-based comparative genomic hybridization detected a 22 Mb duplication of chromosome 11p15.5p14.3 and a 3.7 Mb deletion of chromosome 18q23. The phenotype of the chromosomal rearrangements is probably resulted from a combination of dosage-sensitive genes. Our patient had clinical manifestations of both 18q deletion and BWS.

Clinical and Molecular Diagnosis of Beckwith-Wiedemann Syndrome with Single- or Multi-Locus Imprinting Disturbance

Beckwith-Wiedemann syndrome (BWS) is a clinically and genetically heterogeneous overgrowth disease. BWS is caused by (epi)genetic defects at the 11p15 chromosomal region, which harbors two clusters of imprinted genes, IGF2/H19 and CDKN1C/KCNQ1OT1, regulated by differential methylation of imprinting control regions, H19/IGF2:IG DMR and KCNQ1OT1:TSS DMR, respectively. A subset of BWS patients show multi-locus imprinting disturbances (MLID), with methylation defects extended to other imprinted genes in addition to the disease-specific locus. Specific (epi)genotype-phenotype correlations have been defined in order to help clinicians in the classification of patients and referring them to a timely diagnosis and a tailored follow-up. However, specific phenotypic correlations have not been identified among MLID patients, thus causing a debate on the usefulness of multi-locus testing in clinical diagnosis. Finally, the high incidence of BWS monozygotic twins with discordant phenotypes, the high frequency of BWS among babies conceived by assisted reproductive technologies, and the female prevalence among BWS-MLID cases provide new insights into the timing of imprint establishment during embryo development. In this review, we provide an overview on the clinical and molecular diagnosis of single- and multi-locus BWS in pre- and post-natal settings, and a comprehensive analysis of the literature in order to define possible (epi)genotype-phenotype correlations in MLID patients.

Prenatally diagnosed omphaloceles: Report of 92 cases and association with Beckwith-Wiedemann syndrome

OBJECTIVE

Describe the prevalence, perinatal and long-term outcomes of Beckwith-Wiedemann syndrome (BWS) among prenatally detected omphaloceles.

METHODS

All prenatally diagnosed omphaloceles from 2010 to 2015 within a single tertiary care centre were identified. An echocardiogram and detailed fetal ultrasound were performed, and amniocentesis was offered with karyotype/microarray analysis and BWS molecular testing. Perinatal, neonatal, and long-term outcomes were retrieved for BWS cases.

RESULTS

Among 92 omphaloceles, 62 had additional anomalies. Abnormal karyotypes were identified in 23/62 (37%) non-isolated and 2/30 (7%) isolated cases. One BWS case (5%) was identified among non-isolated omphaloceles and six BWS cases (37.5%) were identified among isolated omphaloceles after exclusion of aneuploidy. Among 19 BWS cases, 21% were conceived by ART. All omphaloceles underwent primary closure. Prenatally, macrosomia and polyhydramnios were seen in 42%. Macroglossia and nephromegaly were more commonly detected postnatally. Preterm birth occurred in 10/19 (53%) cases and cesarean deliveries were performed in 7/19 (40%) cases. Overall mortality was 20% (4/19). Embryonal tumors were diagnosed in 2/16 (12.5%) children, and neurodevelopmental outcomes were normal in 9/12 (75%) survivors.

CONCLUSIONS

After excluding aneuploidy, BWS was identified in 37.5% and 5% of isolated and non-isolated omphaloceles, respectively. Omphaloceles were small-moderate size with good long-term surgical and neurodevelopmental outcomes when isolated.

A Beckwith-Wiedemann syndrome case with de novo 24 Mb duplication of chromosome 11p15.5p14.3

BACKGROUND

Molecular genetic testing for the 11p15-associated imprinting disorder Beckwith-Wiedemann syndrome (BWS) is challenging because of the molecular heterogeneity and complexity of the affected imprinted regions. An integrated molecular approach to analyze the epigenetic-genetic alterations is required for accurate diagnosis of BWS.

CASE PRESENTATION

We reported a Chinese case with BWS detected by SNP array analysis and methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA). The genetic analysis showed a de novo duplication of 24 Mb at 11p15.5p14.3 is much longer than ever reported. MS-MLPA showed copy number changes with a peak height ratio value of 1.5 (three copies) at 11p15. The duplication of paternal origin with increase of methylation index of 0.68 at H19 and decreased methylation index of 0.37 at KCNQ1OT1.

CONCLUSION

Combined chromosome microarray analysis and methylation profiling provided reliable diagnosis for this paternally derived duplication of BWS. The phenotype associated with 11p15 duplications depends on the size, genetic content, parental inheritance and imprinting status. Identification of these rare duplications is crucial for genetic counselling.

Prenatal features in Beckwith-Wiedemann syndrome and indications for prenatal testing

BACKGROUND

Most cases of Beckwith-Wiedemann spectrum (BWSp) are diagnosed after birth and few studies evaluated the prenatal phenotype; here, we investigate these aspects in a large series of patients with BWSp.

METHODS

Eighty-nine patients with BWSp recruited through the BWSp Internal Registry of the Pediatric Genetics Unit of the Regina Margherita Children's Hospital of Torino and through the Italian Association of Patients with BWSp. Data collection was conducted through administration of a personalised questionnaire, interview to patients' parents, review of the clinical records, including prenatal ultrasound (US) and biochemical screening tests, physical examination and review of clinical and molecular data of the patients.

RESULTS

Seventeen patients (19.1%) were conceived through assisted reproductive techniques (ART). Twinning occurred in nine pregnancies (three from ART). Pregnancy biochemical screening tests showed increased alpha-fetoprotein (1.52±0.79 multiples of median (MoM), p=0.001), uEstriol (1.37±0.38 MoM, p<0.001) and total human chorionic gonadotrophin (2.14±2.12 MoM, p=0.008) at 15-18 weeks (n=28). Morphology US scan revealed abdominal and head circumferences higher than normal (1.42±1.10 SD scores, p<0.001 and 0.54±0.88, p<0.001, respectively) with normal femur lengths. Sixty-four cases (71.9%%) had a various combination of US findings, including macrosomia (n=32), omphalocele (n=15), enlargement of abdominal organs (n=6), macroglossia (n=11), adrenal cysts/masses (n=2), nephroureteral anomalies (n=11), polyhydramnios (n=28), placental enlargement (n=2) or mesenchymal dysplasia (n=4).

CONCLUSION

We propose a clinical scoring system for prenatal molecular investigations defining major, minor and supportive criteria among the several features often observed prenatally in BWSp.

Genetic predisposition in pediatric oncology

Identifying patients with a genetic predisposition for developing malignant tumors has a significant impact on both the patient and family. Recognition of genetic predisposition, before diagnosing a malignant pathology, may lead to early diagnosis of a neoplasia. Recognition of a genetic predisposition syndrome after the diagnosis of neoplasia can result in a change of treatment plan, a specific follow-up of adverse treatment effects and, of course, a long-term follow-up focusing on the early detection of a second neoplasia.

Responsible for genetic syndromes that predispose individuals to malignant pathology are germline mutations. These mutations are present in all cells of conception, they can be inherited or can occur de novo.

Several mechanisms of inheritance are described: Mendelian autosomal dominant, Mendelian autosomal recessive, X-linked patterns, constitutional chromosomal abnormality and non-Mendelian inheritance.

In the following review we will present the most important genetic syndromes in pediatric oncology.

Hepatocellular Carcinoma in a 24-Year-Old Female with Beckwith-Wiedemann Syndrome: A Case Report and Review of the Literature

In this report, the case of a 24-year-old female with Beckwith–Wiedemann Syndrome (BWS) who was diagnosed with well-differentiated hepatocellular carcinoma (HCC) is described. While BWS has been associated with childhood embryonal tumors, most commonly Wilms tumors and hepatoblastomas, this is the first case report to describe HCC in an adult with BWS. Although HCC typically occurs in elderly adults or those with underlying liver disease, in this case, we show that HCC can occur in a young adult with BWS without any underlying liver disease.

Phenotypes and epigenetic errors in patients with Beckwith-Wiedemann syndrome in China

BACKGROUND

Beckwith-Wiedemann syndrome (BWS) is primarily caused by epigenetic errors. This study aimed to analyze the relationship between the epigenetic errors and phenotypes of BWS and to evaluate the efficacy of diagnosing BWS using patients' clinical characteristics.

METHODS

Patients clinically diagnosed with BWS were subjected to methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) for (epi)genotyping. The patients' clinical characteristics were analyzed and compared using regression models. The diagnostic efficacy of previous criteria and scoring systems was compared using area under the receiving operating curve (ROC).

RESULTS

The most common clinical features observed in BWS patients were macroglossia (83.2%), abdominal wall defects (71.3%), and ear creases/pits (55.3%). Patients with the loss of methylation at imprinting control 2 (IC2-LOM) and gaining of methylation at imprinting control 1 (IC1-GOM) subtypes had significantly higher frequencies of ear creases/pits and facial nevus flammeus, and visceromegaly, respectively. Paternal uniparental isodisomy (pUPD) was characterized by significantly less macroglossia but more hemihypertrophy. The area under the curve (AUC) was comparably good in both recently developed scoring systems (0.87 for Ibrahim and 0.82 for Brioude.) and in the scoring system developed using the current cohort (0.88).

CONCLUSIONS

This study, which is the largest cohort study of BWS cases in China published to date, confirmed the diagnostic efficacy of a recently developed symptom-based BWS scoring system in a Chinese population. Significant differences exist between the phenotypes of BWS epigenetic subtypes; however, the pattern is similar between Asian and European populations.

Preclinical and Clinical Epigenetic-Based Reconsideration of Beckwith-Wiedemann Syndrome

Epigenetics has achieved a profound impact in the biomedical field, providing new experimental opportunities and innovative therapeutic strategies to face a plethora of diseases. In the rare diseases scenario, Beckwith-Wiedemann syndrome (BWS) is a pediatric pathological condition characterized by a complex molecular basis, showing alterations in the expression of different growth-regulating genes. The molecular origin of BWS is associated with impairments in the genomic imprinting of two domains at the 11p15.5 chromosomal region. The first domain contains three different regions: insulin growth like factor gene (IGF2), H19, and abnormally methylated DMR1 region. The second domain consists of cell proliferation and regulating-genes such as CDKN1C gene encoding for cyclin kinase inhibitor its role is to block cell proliferation. Although most cases are sporadic, about 5-10% of BWS patients have inheritance characteristics. In the 11p15.5 region, some of the patients have maternal chromosomal rearrangements while others have Uniparental Paternal Disomy UPD(11)pat. Defects in DNA methylation cause alteration of genes and the genomic structure equilibrium leading uncontrolled cell proliferation, which is a typical tumorigenesis event. Indeed, in BWS patients an increased childhood tumor predisposition is observed. Here, we summarize the latest knowledge on BWS and focus on the impact of epigenetic alterations to an increased cancer risk development and to metabolic disorders. Moreover, we highlight the correlation between assisted reproductive technologies and this rare disease. We also discuss intriguing aspects of BWS in twinning. Epigenetic therapies in clinical trials have already demonstrated effectiveness in oncological and non-oncological diseases. In this review, we propose a potential "epigenetic-based" approaches may unveil new therapeutic options for BWS patients. Although the complexity of the syndrome is high, patients can be able to lead a normal life but tumor predispositions might impair life expectancy. In this sense epigenetic therapies should have a supporting role in order to guarantee a good prognosis.

Loss-of-function maternal-effect mutations of PADI6 are associated with familial and sporadic Beckwith-Wiedemann syndrome with multi-locus imprinting disturbance

BACKGROUND

PADI6 is a component of the subcortical maternal complex, a group of proteins that is abundantly expressed in the oocyte cytoplasm, but is required for the correct development of early embryo. Maternal-effect variants of the subcortical maternal complex proteins are associated with heterogeneous diseases, including female infertility, hydatidiform mole, and imprinting disorders with multi-locus imprinting disturbance. While the involvement of PADI6 in infertility is well demonstrated, its role in imprinting disorders is less well established.

RESULTS

We have identified by whole-exome sequencing analysis four cases of Beckwith-Wiedemann syndrome with multi-locus imprinting disturbance whose mothers are carriers of PADI6 variants. In silico analysis indicates that these variants result in loss of function, and segregation analysis suggests they act as either recessive or dominant-negative maternal-effect mutations. Genome-wide methylation analysis revealed heterogeneous and extensively altered methylation profiles of imprinted loci in the patients, including two affected sisters, but not in their healthy siblings.

CONCLUSION

Our results firmly establish the role of PADI6 in imprinting disorders. We report loss-of-function maternal-effect variants of PADI6 that are associated with heterogeneous multi-locus imprinting disturbances in the progeny. The rare finding of two siblings affected by Beckwith-Wiedemann syndrome suggests that in some cases, familial recurrence risk of these variants may be high. However, the heterogeneous phenotypes of the other pedigrees suggest that altered oocyte PADI6 function results in stochastic maintenance of methylation imprinting with unpredictable consequences on early embryo health.

(Epi)genetic profiling of extraembryonic and postnatal tissues from female monozygotic twins discordant for Beckwith-Wiedemann syndrome

Background

Beckwith–Wiedemann syndrome (BWS) is an overgrowth disorder caused by defects at the 11p15.5 imprinted region. Many cases of female monozygotic (MZ) twins discordant for BWS have been reported, but no definitive conclusions have been drawn regarding the link between epigenetic defects, twinning process, and gender. Here, we report a comprehensive characterization and follow‐up of female MZ twins discordant for BWS.

Methods

Methylation pattern at 11p15.5 and multilocus methylation disturbance (MLID) profiling were performed by pyrosequencing and MassARRAY in placental/umbilical cord samples and postnatal tissues. Whole‐exome sequencing was carried out to identify MLID causative mutations. X‐chromosome inactivation (XCI) was determined by HUMARA test.

Results

Both twins share KCNQ1OT1:TSS‐DMR loss of methylation (LOM) and MLID in blood and the epigenetic defect remained stable in the healthy twin over time. KCNQ1OT1:TSS‐DMRLOM was nonhomogeneously distributed in placental samples and the twins showed the same severely skewed XCI pattern. No MLID‐causative mutations were identified.

Conclusion

This is the first report on BWS‐discordant twins with methylation analyses extended to extraembryonic tissues. The results suggest that caution is required when attempting prenatal diagnosis in similar cases. Although the causative mechanism underlying LOM remains undiscovered, the XCI pattern and mosaic LOM suggest that both twinning and LOM/MLID occurred after XCI commitment.

Modeling human epigenetic disorders in mice: Beckwith-Wiedemann syndrome and Silver-Russell syndrome

Genomic imprinting, a phenomenon in which the two parental alleles are regulated differently, is observed in mammals, marsupials and a few other species, including seed-bearing plants. Dysregulation of genomic imprinting can cause developmental disorders such as Beckwith-Wiedemann syndrome (BWS) and Silver-Russell syndrome (SRS). In this Review, we discuss (1) how various (epi)genetic lesions lead to the dysregulation of clinically relevant imprinted loci, and (2) how such perturbations may contribute to the developmental defects in BWS and SRS. Given that the regulatory mechanisms of most imprinted clusters are well conserved between mice and humans, numerous mouse models of BWS and SRS have been generated. These mouse models are key to understanding how mutations at imprinted loci result in pathological phenotypes in humans, although there are some limitations. This Review focuses on how the biological findings obtained from innovative mouse models explain the clinical features of BWS and SRS.

Cancer incidence and spectrum among children with genetically confirmed Beckwith-Wiedemann spectrum in Germany: a retrospective cohort study

BACKGROUND

Beckwith-Wiedemann syndrome (BWS) is a cancer predisposition syndrome caused by defects on chromosome 11p15.5. The quantitative cancer risks in BWS patients depend on the underlying (epi)genotype but have not yet been assessed in a population-based manner.

METHODS

We identified a group of 321 individuals with a molecularly confirmed diagnosis of BWS and analysed the cancer incidence up to age 15 years and cancer spectrum by matching their data with the German Childhood Cancer Registry.

RESULTS

We observed 13 cases of cancer in the entire BWS cohort vs 0.4 expected. This corresponds to a 33-fold increased risk (standardised incidence ratio (SIR) = 32.6; 95% confidence interval = 17.3-55.7). The specific cancers included hepatoblastoma (n = 6); nephroblastoma (n = 4); astrocytoma (n = 1); neuroblastoma (n = 1) and adrenocortical carcinoma (n = 1). The cancer SIR was highest in patients with a paternal uniparental disomy of 11p15.5 (UPDpat). A high cancer risk remained when cases of cancer diagnosed prior to the BWS diagnosis were excluded.

CONCLUSIONS

This study confirms an increased cancer risk in children with BWS. Our findings suggest that the highest cancer risk is associated with UPDpat. We were unable to confirm an excessive cancer risk in patients with IC1 gain of methylation (IC1-GOM) and this finding requires further investigation.

Clinical and molecular features of children with Beckwith-Wiedemann syndrome in China: a single-center retrospective cohort study

Background

Beckwith-Wiedemann syndrome (BWS) is a genetic overgrowth disorder with variable clinical features and cancer predisposition. In this study, we aim to characterize the clinical features and molecular defects of BWS patients in China.

Methods

Thirty-one patients with clinical suspicion of BWS were retrospectively recruited to the study from Shanghai Children’s Hospital between January 2014 and December 2017. Clinical data, including demographics, clinical features, and molecular testing results were extracted and systematically analyzed.

Results

Twenty-one patients with a BWS score ≥ 4 (6, IQR 4, 7) were clinically diagnosed with BWS, and 10 children with a BWS score ≥ 2 and < 4 (2, IQR 2, 3) were clinically suspected BWS patients. The most common cardinal feature of clinically diagnosed patients was macroglossia (71.4%) followed by lateralized overgrowth (33.3%) and exomphalos (14.3%), and the major suggestive features were umbilical hernia and/or diastasis recti (65.0%) and ear creases or pits (61.9%). Among 10 clinically suspected BWS patients, macroglossia and lateralized overgrowth were observed in 3 (30%) and 2 (20%) patients, and umbilical hernia and/or diastasis recti occurred in 7 (70.0%) patients. Seven (33.3%) clinically diagnosed patients and 3 (30%) suspected patients were identified with loss of methylation at KCNQ1OT1:TSS differentially methylated region (DMR; IC2 LOM), 5 (23.8%) clinically diagnosed BWS patients were identified with gain of methylation at H19/IGF2:IG-DMR (IC1 GOM), and 1 (4.8%) clinically diagnosed BWS patients was identified with paternal uniparental isodisomy 11 (pUPD11). The phenotype-genotype correlation analysis showed no significant difference among patients with IC2 LOM, IC1 GOM, and pUPD11.

Conclusions

The current study presents the first cohort study of BWS patients in mainland China. The clinical and molecular features of the patients are similar to those of other reported BWS patients in the Chinese population.

Syndromic Disorders Caused by Disturbed Human Imprinting

Imprinting disorders are a group of congenital diseases caused by dysregulation of genomic imprinting, affecting prenatal and postnatal growth, neurocognitive development, metabolism and cancer predisposition. Aberrant expression of imprinted genes can be achieved through different mechanisms, classified into epigenetic - if not involving DNA sequence change - or genetic in the case of altered genomic sequence. Despite the underlying mechanism, the phenotype depends on the parental allele affected and opposite phenotypes may result depending on the involvement of the maternal or the paternal chromosome. Imprinting disorders are largely underdiagnosed because of the broad range of clinical signs, the overlap of presentation among different disorders, the presence of mild phenotypes, the mitigation of the phenotype with age and the limited availability of molecular techniques employed for diagnosis. This review briefly illustrates the currently known human imprinting disorders, highlighting endocrinological aspects of pediatric interest.

Epigenetic Abnormalities of 11p15.5 Region in Beckwith-Wiedemann Syndrome - A Report of Eight Indian Cases

OBJECTIVES

To report a phenotypic series of eight patients of Beckwith-Wiedemann Syndrome (BWS) with abnormalities of 11p15.5 region to highlight the spectrum of phenotypic manifestations.

METHODS

All the cases were evaluated using Methylation Specific Multiplex Ligation Dependent Probe Amplification (MS-MLPA) of 11p15.5 region to detect the abnormal methylation status of ICR1 (H19DR) and ICR2 (KvDMR) regions.

RESULTS

The median age at diagnosis was 5.7 mo (range 1.5-13 mo) with female preponderance. Macroglossia, ear creases and abdominal wall defects were the major features. Hypomethylation at ICR2 and hypermethylation at ICR1 was observed in 6/8 and 2/8 patients respectively. No specific genotype and phenotype correlation was observed.

CONCLUSIONS

This report highlights the major clinical features of BWS that should prompt pediatricians to offer genetic testing to evaluate the epigenetic abnormalities using MS-MLPA, as it not only helps in appropriate counseling but also provides further guidance about the tumor risk surveillance.

Overgrowth Syndromes-Evaluation, Diagnosis, and Management

Abnormally excessive growth results from perturbation of a complex interplay of genetic, epigenetic, and hormonal factors that orchestrate human growth. Overgrowth syndromes generally present with inherent health concerns and, in some instances, an increased risk of tumor predisposition that necessitate prompt diagnosis and appropriate referral. In this review, we introduce some of the more common overgrowth syndromes, along with their molecular mechanisms, diagnostics, and medical complications for improved recognition and management of patients affected with these disorders.

Characterization of the Beckwith-Wiedemann spectrum: Diagnosis and management

Beckwith-Wiedemann syndrome (BWS) is the most common epigenetic overgrowth and cancer predisposition disorder. Due to both varying molecular defects involving chromosome 11p15 and tissue mosaicism, patients can present with a variety of clinical features, leading to the newly defined Beckwith-Wiedemann spectrum (BWSp). The BWSp can be further divided into three subsets of patients: those presenting with classic features, those presenting with isolated lateralized overgrowth (ILO) and those not fitting into the previous two categories, termed atypical BWSp. Previous reports of patients with BWS have focused on those with the more recognizable, classic features, and limited information is available on those who fit into the atypical and ILO categories. Here, we present the first cohort of patients recruited across the entire BWSp, describe clinical features and molecular diagnostic characteristics, and provide insight into practical diagnosis and management recommendations that we have gained from this cohort.

Overgrowth Syndrome

Large offspring syndrome (LOS) is a fetal overgrowth condition in bovines most often observed in offspring conceived with the use of assisted reproductive technologies (ART). Phenotypes observed in LOS include, overgrowth, enlarged tongues, umbilical hernias, muscle and skeleton malformations, abnormal organ growth and placental development. Although LOS cases have only been reported to be associated with ART, fetal overgrowth can occur spontaneously in cattle (S-LOS). S-LOS refers to oversized calves that are born at normal gestation lengths. ART-induced LOS has been characterized as an epigenetic syndrome, more specifically, a loss-of-imprinting condition. We propose that S-LOS is also a loss-of-imprinting condition.

A retrospective analysis of the prevalence of imprinting disorders in Estonia from 1998 to 2016

Imprinting disorders (ImpDis) represent a small group of rare congenital diseases primarily affecting growth, development, and the hormonal and metabolic systems. The aim of present study was to identify the prevalence of the ImpDis in Estonia, to describe trends in the live birth prevalence of these disorders between 1998 and 2016, and to compare the results with previously published data. We retrospectively reviewed the records of all Estonian patients since 1998 with both molecularly and clinically diagnosed ImpDis. A prospective study was also conducted, in which all patients with clinical suspicion for an ImpDis were molecularly analyzed. Eighty-seven individuals with ImpDis were identified. Twenty-seven (31%) of them had Prader-Willi syndrome (PWS), 15 (17%) had Angelman syndrome (AS), 15 (17%) had Silver-Russell syndrome (SRS), 12 (14%) had Beckwith-Wiedemann syndrome (BWS), 10 (11%) had pseudo- or pseudopseudohypoparathyroidism, four had central precocious puberty, two had Temple syndrome, one had transient neonatal diabetes mellitus, and one had myoclonus-dystonia syndrome. One third of SRS and BWS cases fulfilled the diagnostic criteria for these disorders, but tested negative for genetic abnormalities. Seventy-six individuals were alive as of January 1, 2018, indicating the total prevalence of ImpDis in Estonia is 5.8/100,000 (95% CI 4.6/100,000-7.2/100,000). The minimum live birth prevalence of all ImpDis in Estonia in 2004-2016 was 1/3,462, PWS 1/13,599, AS 1/27,198, BWS 1/21,154, SRS 1/15,866, and PHP/PPHP 1/27,198. Our results are only partially consistent with previously published data. The worldwide prevalence of SRS and GNAS-gene-related ImpDis is likely underestimated and may be at least three times higher than expected.

Unbalanced segregation of a paternal t(9;11)(p24.3;p15.4) translocation causing familial Beckwith-Wiedemann syndrome: a case report

Background

The vast majority of cases with Beckwith-Wiedemann syndrome (BWS) are caused by a molecular defect in the imprinted chromosome region 11p15.5. The underlying mechanisms include epimutations, uniparental disomy, copy number variations, and structural rearrangements. In addition, maternal loss-of-function mutations in CDKN1C are found. Despite growing knowledge on BWS pathogenesis, up to 20% of patients with BWS phenotype remain without molecular diagnosis.

Case presentation

Herein, we report an Iranian family with two females affected with BWS in different generations. Bisulfite pyrosequencing revealed hypermethylation of the H19/IGF2: intergenic differentially methylated region (IG DMR), also known as imprinting center 1 (IC1) and hypomethylation of the KCNQ1OT1: transcriptional start site (TSS) DMR (IC2). Array CGH demonstrated an 8 Mb duplication on chromosome 11p15.5p15.4 (205,827-8,150,933) and a 1 Mb deletion on chromosome 9p24.3 (209,020-1,288,114). Chromosome painting revealed that this duplication-deficiency in both patients is due to unbalanced segregation of a paternal reciprocal t(9;11)(p24.3;p15.4) translocation.

Conclusions

This is the first report of a paternally inherited unbalanced translocation between the chromosome 9 and 11 short arms underlying familial BWS. Copy number variations involving the 11p15.5 region are detected by the consensus diagnostic algorithm. However, in complex cases which do not only affect the BWS region itself, characterization of submicroscopic chromosome rearrangements can assist to estimate the recurrence risk and possible phenotypic outcomes.

Longitudinal Monitoring of Alpha-Fetoprotein by Dried Blood Spot for Hepatoblastoma Screening in Beckwith⁻Wiedemann Syndrome

BACKGROUND

Hepatoblastoma screening in the Beckwith⁻Wiedemann spectrum (BWSp) is currently based on measuring a specific serum marker alpha-fetoprotein (αFP) every three months until the fourth birthday. Frequent blood draws can be a burden for patients and their families.

METHODS

We have developed a less invasive alternative testing method based on measuring αFPs from dried blood spots (DBS). The method was validated with 259 simultaneous plasma and DBS αFP measurements in 171 children (132 controls and 39 patients with BWSp).

RESULTS

The DBS and plasma measurements overlapped across the wide range of αFP concentrations independent of patient age (p < 0.0001), demonstrating the utility of this method for longitudinal monitoring. Occasional differences between measurements by the two techniques fell within standard laboratory error and would not alter clinical management.

CONCLUSIONS

This novel method shows consistent overlap with the traditional blood draws, thereby demonstrating its utility for hepatoblastoma screening in this setting and alleviating the burden of frequent blood draws. This also may help increase patient compliance and reduce costs of health care screening. The DBS-based method for the measurement of cancer biomarkers may also be applied to several other chronic diseases with increased risks of αFP-producing liver tumors.

Comparison of Quantitative Analysis of Methylated Alleles Real-Time PCR and Methylation-Specific MLPA for Molecular Diagnosis of Beckwith-Wiedemann Syndrome

<b><i>Background/Aims:</i></b> Beckwith-Wiedemann syndrome (BWS) is a congenital overgrowth disorder predisposing to tumorigenesis caused by abnormal expression or function of imprinted genes of the chromosome 11p15.5 imprinting gene cluster. This real-time PCR-based assay determines the methylation status of a selected CpG island and has been proposed for use in high-throughput methylation analysis. <b><i>Methods:</i></b> Here, we use quantitative analysis of methylated alleles (QAMA) for the detection of methylation status of the KCNQ10T1 gene, in a region immediately upstream of the transcription initiation site, and the CTCF binding site 6, located approximately 2 kb upstream of the SmaI site currently used for clinical laboratory testing. We assayed a series of controls and patients diagnosed with BWS at two different loci at 11p15.5 to assess the diagnostic yield of QAMA PCR for clinical laboratory testing. <b><i>Results:</i></b> These results compare favorably with methylation-specific multiple ligation probe amplification (MS-MLPA) analysis at both differentially methylated region (DMR)1 and DMR2. There are several advantages of the QAMA PCR over MS-MLPA. The QAMA PCR is less labor-intensive and therefore more cost-effective and does not require dedicated analysis software. A second advantage is that the assay is amenable to high-throughput analysis. <b><i>Conclusions:</i></b> The small sample size reflects the rare nature of this epigenetic disorder, and the range of ages was quite wide, as was the degree of disease severity. Therefore, further validation with larger cohorts is warranted.

Defining an optimal time window to screen for hepatoblastoma in children with Beckwith-Wiedemann syndrome

Patients with Beckwith-Wiedemann spectrum (BWSp) undergo quarterly alpha-fetoprotein measurement for hepatoblastoma (HB) screening up to 4 years of age, paralleling the epidemiology of nonsyndromic HB. However, specific data on the timing of HB development in BWSp are lacking. Here we compare the timing of presentation of HBs in BWSp with a control cohort of consecutive HB cases, demonstrating that halving screening duration of screening procedures in BWSp likely will not impact its effectiveness.

Diseases Predisposing to Adrenocortical Malignancy (Li-Fraumeni Syndrome, Beckwith-Wiedemann Syndrome, and Carney Complex)

Adrenocortical malignancies can occur in the context of several tumor predisposition syndromes.The Carney complex (CNC) is responsible for the majority of primary pigmented nodular adrenal diseases and is more rarely associated with adrenocortical carcinoma (ACC). Other core manifestations of CNC include cardiac and cutaneous myxomas, lentiginosis, somatotroph pituitary adenomas, Sertoli tumors, melanocytic schwannoma, and thyroid, breast, and bone tumors. CNC is mostly due to germline inactivating mutations of PRKAR1A.The majority of childhood ACC are related to genetic predisposition. The Beckwith-Wiedemann syndrome (BWS) is an overgrowth and tumor predisposition syndrome due to genetic or epigenetic alterations at the 11p15 locus. Classical tumor spectrum of BWS includes embryonal tumors and childhood ACC. The Li-Fraumeni syndrome (LFS) is a devastating tumor predisposition syndrome, due to germline inactivating mutations of TP53, and characterized by a high, various, and early-onset cancer risk. LFS spectrum includes premenopausal breast cancer, soft-tissue sarcoma, osteosarcoma, central nervous system tumor, and ACC, accounting for 50-80% of pediatric cases. Finally, germline predisposition affects up to 10% of adult ACC patients, mostly in part of LFS and Lynch syndrome.This chapter focuses on the diagnosis, screening, and management of adrenal tumors in part of these tumor predisposition syndromes.

Genetic variation affecting DNA methylation and the human imprinting disorder, Beckwith-Wiedemann syndrome

Background

Beckwith-Wiedemann syndrome (BWS) is an imprinting disorder with a population frequency of approximately 1 in 10,000. The most common epigenetic defect in BWS is a loss of methylation (LOM) at the 11p15.5 imprinting centre, KCNQ1OT1 TSS-DMR, and affects 50% of cases. We hypothesised that genetic factors linked to folate metabolism may play a role in BWS predisposition via effects on methylation maintenance at KCNQ1OT1 TSS-DMR.

Results

Single nucleotide variants (SNVs) in the folate pathway affecting methylenetetrahydrofolate reductase (MTHFR), methionine synthase reductase (MTRR), 5-methyltetrahydrofolate-homocysteine S-methyltransferase (MTR), cystathionine beta-synthase (CBS) and methionine adenosyltransferase (MAT1A) were examined in 55 BWS patients with KCNQ1OT1 TSS-DMR LOM and in 100 unaffected cases. MTHFR rs1801133: C>T was more prevalent in BWS with KCNQ1OT1 TSS-DMR LOM (p < 0.017); however, the relationship was not significant when the Bonferroni correction for multiple testing was applied (significance, p = 0.0036). None of the remaining 13 SNVs were significantly different in the two populations tested. The DNMT1 locus was screened in 53 BWS cases, and three rare missense variants were identified in each of three patients: rs138841970: C>T, rs150331990: A>G and rs757460628: G>A encoding NP_001124295 p.Arg136Cys, p.His1118Arg and p.Arg1223His, respectively. These variants have population frequencies of less than 1 in 1000 and were absent from 100 control cases. Functional characterization using a hemimethylated DNA trapping assay revealed a reduced methyltransferase activity relative to wild-type DNMT1 for each variant ranging from 40 to 70% reduction in activity.

Conclusions

This study is the first to examine folate pathway genetics in BWS and to identify rare DNMT1 missense variants in affected individuals. Our data suggests that reduced DNMT1 activity could affect maintenance of methylation at KCNQ1OT1 TSS-DMR in some cases of BWS, possibly via a maternal effect in the early embryo. Larger cohort studies are warranted to further interrogate the relationship between impaired MTHFR enzymatic activity attributable to MTHFR rs1801133: C>T, dietary folate intake and BWS.

Electronic supplementary material

The online version of this article (10.1186/s13148-018-0546-4) contains supplementary material, which is available to authorized users.

Expert consensus document: Clinical and molecular diagnosis, screening and management of Beckwith-Wiedemann syndrome: an international consensus statement

Beckwith-Wiedemann syndrome (BWS), a human genomic imprinting disorder, is characterized by phenotypic variability that might include overgrowth, macroglossia, abdominal wall defects, neonatal hypoglycaemia, lateralized overgrowth and predisposition to embryonal tumours. Delineation of the molecular defects within the imprinted 11p15.5 region can predict familial recurrence risks and the risk (and type) of embryonal tumour. Despite recent advances in knowledge, there is marked heterogeneity in clinical diagnostic criteria and care. As detailed in this Consensus Statement, an international consensus group agreed upon 72 recommendations for the clinical and molecular diagnosis and management of BWS, including comprehensive protocols for the molecular investigation, care and treatment of patients from the prenatal period to adulthood. The consensus recommendations apply to patients with Beckwith-Wiedemann spectrum (BWSp), covering classical BWS without a molecular diagnosis and BWS-related phenotypes with an 11p15.5 molecular anomaly. Although the consensus group recommends a tumour surveillance programme targeted by molecular subgroups, surveillance might differ according to the local health-care system (for example, in the United States), and the results of targeted and universal surveillance should be evaluated prospectively. International collaboration, including a prospective audit of the results of implementing these consensus recommendations, is required to expand the evidence base for the design of optimum care pathways.