Fetal growth patterns in Beckwith-Wiedemann syndrome

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.

Occurrence of Hepatoblastomas in Patients with Beckwith-Wiedemann Spectrum (BWSp)

Patients with Beckwith-Wiedemann syndrome (BWS), an epigenetic imprinting disorder involving alterations in genes at the 11p15 chromosomal location, are predisposed to develop hepatoblastomas (HBs), which are rare embryonal liver tumors. Tumors can develop after a BWS diagnosis or, conversely, can be the presenting feature leading to a subsequent diagnosis. While HBs are the cardinal tumors of BWS, not all patients with the BWS spectrum will develop HBs. This observation has led to many hypotheses, including genotype-associated risk, tissue mosaicism, and tumor-specific second hits. To explore these hypotheses, we present the largest cohort of patients with BWS and HBs to date. Our cohort comprised 16 cases, and we broadened our sample size by searching the literature for all cases of BWS with HBs. From these isolated case studies, we amassed another 34 cases, bringing the total number to 50 cases of BWS-HB. We observed that paternal uniparental isodisomy (upd(11)pat) was the most common genotype, representing 38% of cases. The next most common genotype was IC2 LOM, representing 14% of cases. Five patients had clinical BWS without a molecular diagnosis. To investigate the potential mechanism of HBs in BWS, we analyzed normal liver and HB samples from eight cases and isolated tumor samples from another two cases. These samples underwent methylation testing, and 90% of our tumor samples underwent targeted cancer next-generation sequencing (NGS) panels. These matched samples provided novel insights into the oncogenesis of HBs in BWS. We found that 100% of the HBs that underwent NGS panel testing had variants in the CTNNB1 gene. We further identified three distinct groups of BWS-HB patients based on epigenotype. We also demonstrated epigenotype mosaicism, where 11p15 alterations can differ between the blood, HB, and normal liver. In light of this epigenotype mosaicism, tumor risk assessment based on blood profiling may not be accurate. Therefore, universal screening is recommended for all patients with BWS.

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.

Guided Growth in Leg Length Discrepancy in Beckwith-Wiedemann Syndrome: A Consecutive Case Series

Beckwith-Wiedemann Syndrome (BWS) is a rare genetic disorder characterized by overgrowth, macroglossia, abdominal wall defects, neonatal hypoglycemia, predisposition to embryonal tumor, lateralized overgrowth, and leg length discrepancy (LLD), which can affect normal posture and gait. Aim of this study was to evaluate the effects of guided growth (temporary epiphysiodesis technique) as LLD management in BWS patients. Between 2007 and 2021, 22 BWS patients (15 F, 7 M) with a mean age of 7.9 years (2.9–14.4) and a mean LLD at first surgery of 3.65 cm (2–10), underwent temporary proximal tibial (PTE) and distal femur epiphysiodesis (DFE). In 18 patients the first surgical procedure was PTE, in one, DFE, and in 3 cases, PTE and DFE at the same time, respectively. Eleven patients reached equality of leg length after a mean follow-up of 7.7 years (3.7–13.0) and mean age of 13.3 years (12.7–27.5); 10 patients underwent 3 surgical procedures, one 7 procedures. Fifteen patients had no complications. No severe complications, infection, articular stiffness, or neuro-vascular lesions occurred in remaining patients; complications included secondary varus or valgus axial deviation in a total of 6 patients, and two screw breakages in two patients. Guided growth as a minimally invasive procedure seems efficient for LLD treatment with low complication rate in BWS patients.

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.

Prenatal molecular testing and diagnosis of Beckwith-Wiedemann syndrome

OBJECTIVE

The objective of this study was to describe molecular findings and phenotypic features among individuals referred for prenatal Beckwith-Wiedemann syndrome (BWS) testing.

METHODS

Molecular diagnostic testing was performed using a sensitive quantitative real-time PCR-based assay capable of detecting mosaic methylation to the level of 3% at IC1 and IC2. Sanger sequencing of CDKN1C was performed in cases with normal methylation.

RESULTS

Of the 94 patients tested, a molecular diagnosis was identified for 25.5% of cases; 70.9% of diagnosed cases had loss of methylation at IC2, 4.2% had gain of methylation at IC1, 12.5% had paternal uniparental isodisomy, and 12.5% had CDKN1C loss-of-function variants. Methylation level changes in prenatal cases were significantly greater than changes identified in cases tested after birth. Cases with a prenatal molecular diagnosis had a significantly greater number of BWS-associated phenotypic features. The presence of either macroglossia or placentomegaly was most predictive of a BWS diagnosis.

CONCLUSION

Our results support the consensus statement advocating BWS molecular testing for all patients with one or more BWS-associated prenatal features and suggest that low-level mosaic methylation changes may be uncommon among prenatal BWS diagnoses.

Sperm Global DNA Methylation (SGDM) in Semen of Healthy Dogs

Male infertility is an emerging problem in both humans and animals, and the knowledge of its causes is the first step to identifying new diagnostic and therapeutic strategies. In humans, alteration of sperm DNA methylation have been related to poor quality semen, impaired seminal parameters, azoospermia and reduced fertility. Although semen analysis is routinely used to evaluate the male reproductive potential in the canine species, no authors have attempted to relate semen characteristics to the sperm global DNA methylation (SGDM). The aim of this study was to evaluate the SGDM level in healthy dogs and to correlate it with semen parameters that are currently used in dog semen analyses. Conventional and unconventional (sperm DNA fragmentation and SGDM) seminal parameters of thirty dogs from different breeds were evaluated. A positive correlation was found between SGDM and sperm concentration (r = 0.41; p < 0.05), and total sperm count (r = 0.61; p < 0.001); SGDM was significantly lower in oligozoospermic vs non-oligozoospermic dogs (4.3% vs. 8.7%; p < 0.005). Our findings suggest that SGDM levels are related to conventional seminal parameters, and could be used as a marker of testis function and spermatogenesis in dogs.

Investigation of (epi)genotype causes and follow-up manifestations in the patients with classical and atypical phenotype of Beckwith-Wiedemann spectrum

Beckwith-Wiedemann syndrome (BWS) is a genomic imprinting disorder, characterized by macroglossia, abdominal wall defects, lateralized overgrowth, and predisposition to embryonal tumors. It is caused by the defect of imprinted genes on chromosome 11p15.5, regulated by imprinting control (IC) domains, IC1, and IC2. Rarely, CDKN1C and chromosomal changes can be detected. The aim of this study is to retrospectively evaluate 55 patients with BWS using the new diagnostic criteria developed by the BWS consensus, and to investigate (epi)genetic changes and follow-up findings in classic and atypical phenotypes. Loss of methylation in IC2 region (IC2-LoM), 11p15.5 paternal uniparental disomy (pUPD11), and methylation gain in IC1 region (IC1-GoM) are detected in 31, eight, and five patients, respectively. Eleven patients have had no molecular defects. Thirty-five patients are classified as classical and 20 as atypical phenotype. Patients with classical phenotype are more frequent in the IC2-LoM (25/31), while patients with atypical phenotype are common in the pUPD11 group (5/8). Malignant tumors have developed in six patients (10.9%); three of these patients have IC1-GoM, two pUPD11, one IC2-LoM genotype, and four an atypical phenotype. We observed that the face was round in the infantile period and elongated as the child grew-up, developing prognathism and becoming asymmetrical if hemi-macroglossia was present in the classical phenotype. These findings were mild in the atypical phenotype. These results support the importance of using the new diagnostic criteria to facilitate the diagnosis of patients with atypical phenotype who have higher tumors risk. This study also provides important information about facial gestalt.

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.

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.

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.

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.

Phenotype evolution and health issues of adults with Beckwith-Wiedemann syndrome

BACKGROUND

Beckwith-Wiedemann syndrome (BWS) phenotype usually mitigates with age and data on adulthood are limited. Our study aims at reporting phenotype evolution and health issues in adulthood.

METHODS

34 patients (16 males), aged 18-58 years (mean 28.5) with BWS were enrolled.

RESULTS

26 patients were molecularly confirmed, 5 tested negative, and 3 were not tested. Final tall stature was present in 44%. Four patients developed Wilms' Tumor (2, 3, 5, and 10 years, respectively); one hepatoblastoma (22 years); one acute lymphoblastic leukemia (21 years); one adrenal adenoma and testicular Sertoli cell tumor (22 and 24 years, respectively); and three benign tumors (hepatic haemangioma, uterine myoma, and mammary fibroepithelioma). Surgery for BWS-related features was required in 85%. Despite surgical correction several patients presented morbidity and sequelae of BWS pediatric issues: pronunciation/swallow difficulties (n = 9) due to macroglossia, painful scoliosis (n = 4) consistent with lateralized overgrowth, recurrent urolithiasis (n = 4), azoospermia (n = 4) likely consequent to cryptorchidism, severe intellectual disability (n = 2) likely related to neonatal asphyxia and diabetes mellitus (n = 1) due to subtotal pancreatectomy for intractable hyperinsulinism. Four patients (two males) had healthy children (three physiologically conceived and one through assisted reproductive technology).

CONCLUSIONS

Adult health conditions in BWS are mostly consequent to pediatric issues, underlying the preventive role of follow-up strategies in childhood. Malignancy rate observed in early adulthood in this small cohort matches that observed in the first decade of life, cumulatively raising tumor rate in BWS to 20% during the observation period. Further studies are warranted in this direction.

Prenatal imaging throughout gestation in Beckwith-Wiedemann syndrome

PURPOSE

Prenatal occurrence and timing of appearance of associated features in Beckwith-Wiedemann syndrome (BWS) are unknown. We reviewed our BWS patients with serial fetal imaging and correlated these with postnatal findings.

METHODS

All BWS patients with fetal ultrasound (US) or magnetic resonance imaging (MRI) from 2000 to 2016 were reviewed to determine the presence of polyhydramnios, placentamegaly, macrosomia, macroglossia, retrognathia, omphalocele, visceromegaly, and hemihypertrophy. These observations were correlated with postnatal findings. Data were analyzed by Mann-Whitney U test.

RESULTS

Nine BWS patients underwent 42 fetal imaging studies with median of five (range of two to six) studies per patient between 13 and 35 weeks gestation. All prenatal findings were confirmed postnatally with complete concordance. All patients with omphalocele were detected early in gestation but other postnatal findings less predictably so. All omphaloceles were small, and were found significantly earlier in gestation than macrosomia (P = 0.004) and macroglossia (P = 0.012). Visceromegaly and retrognathia were less frequent, with no significant differences in median gestational age from omphalocele when prenatally identified.

CONCLUSIONS

In BWS, omphalocele is the most common prenatal finding and routinely observed in early gestation with 100% accuracy. Associated findings of macrosomia, macroglossia, visceromegaly, and retrognathia, when present, are detected later in gestation. Imaging in later gestation may reveal additional abnormalities that support a BWS diagnosis.

Beckwith-Wiedemann syndrome in diverse populations

Beckwith-Wiedemann syndrome (BWS) is the most common epigenetic overgrowth disorder and presents with patients affected by a variety of clinical features. Although genotype-phenotype correlations have been demonstrated in BWS and although BWS has been reported to occur equally among racial and ethnic backgrounds, no study to date has evaluated the frequency of findings in different backgrounds. In this study, we evaluated the incidence of clinical features and molecular diagnoses among patients with BWS in Caucasian, Mixed, and non-Caucasian groups. These results suggest that clinical features and molecular diagnoses differ between race/ethnicity groups and raise the possibility of race and ethnicity effects on genotype-phenotype correlations in BWS.

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.

Exosomes of pasteurized milk: potential pathogens of Western diseases

Milk consumption is a hallmark of western diet. According to common believes, milk consumption has beneficial effects for human health. Pasteurization of cow's milk protects thermolabile vitamins and other organic compounds including bioactive and bioavailable exosomes and extracellular vesicles in the range of 40-120 nm, which are pivotal mediators of cell communication via systemic transfer of specific micro-ribonucleic acids, mRNAs and regulatory proteins such as transforming growth factor-β. There is compelling evidence that human and bovine milk exosomes play a crucial role for adequate metabolic and immunological programming of the newborn infant at the beginning of extrauterine life. Milk exosomes assist in executing an anabolic, growth-promoting and immunological program confined to the postnatal period in all mammals. However, epidemiological and translational evidence presented in this review indicates that continuous exposure of humans to exosomes of pasteurized milk may confer a substantial risk for the development of chronic diseases of civilization including obesity, type 2 diabetes mellitus, osteoporosis, common cancers (prostate, breast, liver, B-cells) as well as Parkinson's disease. Exosomes of pasteurized milk may represent new pathogens that should not reach the human food chain.

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.

Diagnosis and Management of Beckwith-Wiedemann Syndrome

Beckwith-Wiedemann syndrome (BWS) is a human genomic imprinting disorder that presents with a wide spectrum of clinical features including overgrowth, abdominal wall defects, macroglossia, neonatal hypoglycemia, and predisposition to embryonal tumors. It is associated with genetic and epigenetic changes on the chromosome 11p15 region, which includes two imprinting control regions. Here we review strategies for diagnosing and managing BWS and delineate commonly used genetic tests to establish a molecular diagnosis of BWS. Recommended first-line testing assesses DNA methylation and copy number variation of the BWS region. Tissue mosaicism can occur in patients with BWS, posing a challenge for genetic testing, and a negative test result does not exclude a diagnosis of BWS. Further testing should analyze additional tissue samples or employ techniques with higher diagnostic yield. Identifying the BWS molecular subtype is valuable for coordinating patient care because of the (epi)genotype-phenotype correlations, including different risks and types of embryonal tumors.

Placental Pathology in Beckwith-Wiedemann Syndrome According to Genotype/Epigenotype Subgroups

OBJECTIVES

To evaluate the frequency of placental pathological lesions in Beckwith-Wiedemann syndrome (BWS), an overgrowth disorder that exhibits etiologic molecular heterogeneity and variable phenotypic expression.

MATERIALS AND METHODS

The study included 60 BWS patients with a proven molecular diagnosis and a placental pathological examination. Placentomegaly, placental mesenchymal dysplasia (PMD), chorangioma/chorangiomatosis, and extravillous trophoblastic (EVT) cytomegaly were evaluated and their frequencies in the different molecular subgroups were compared. Immunohistochemistry and fluorescent in situ hybridization (FISH) were performed on EVT cytomegaly.

RESULTS

Placentomegaly was found in 70.9% of cases, PMD in 21.7%, chorangioma/chorangiomatosis in 23.3%, and EVT cytomegaly in 21.7%; there was no significant intergroup difference. EVT cytomegaly showed loss of p57 expression, increased Ki67 proliferating index, and polyploidy on FISH analysis.

CONCLUSIONS

There was no genotype/epigenotype-phenotype correlation concerning placental lesions in BWS. Diffuse EVT cytomegaly with polyploidy may represent a placental finding suggestive of BWS.

Genetic and Epigenetic Control of CDKN1C Expression: Importance in Cell Commitment and Differentiation, Tissue Homeostasis and Human Diseases

The CDKN1C gene encodes the p57^Kip2 protein which has been identified as the third member of the CIP/Kip family, also including p27^Kip1 and p21^Cip1. In analogy with these proteins, p57^Kip2 is able to bind tightly and inhibit cyclin/cyclin-dependent kinase complexes and, in turn, modulate cell division cycle progression. For a long time, the main function of p57^Kip2 has been associated only to correct embryogenesis, since CDKN1C-ablated mice are not vital. Accordingly, it has been demonstrated that CDKN1C alterations cause three human hereditary syndromes, characterized by altered growth rate. Subsequently, the p57^Kip2 role in several cell phenotypes has been clearly assessed as well as its down-regulation in human cancers. CDKN1C lies in a genetic locus, 11p15.5, characterized by a remarkable regional imprinting that results in the transcription of only the maternal allele. The control of CDKN1C transcription is also linked to additional mechanisms, including DNA methylation and specific histone methylation/acetylation. Finally, long non-coding RNAs and miRNAs appear to play important roles in controlling p57^Kip2 levels. This review mostly represents an appraisal of the available data regarding the control of CDKN1C gene expression. In addition, the structure and function of p57^Kip2 protein are briefly described and correlated to human physiology and diseases.

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.

Beckwith-Wiedemann Syndrome Review: A Guide for the Neonatal Nurse

Beckwith-Wiedemann syndrome (BWS) is the most common pediatric overgrowth syndrome. Features characteristic of the BWS phenotype include both physical attributes, such as macroglossia, abdominal wall defects, gigantism, nevus flammeus, visceromegaly, and mid-face hypoplasia, as well as biochemical abnormalities such as hypoglycemia. It is essential for the neonatal nurse to be able to recognize BWS in the patient's early years of life because of the increased frequency of medical complications, malformations, and the increased risk of embryonic malignancies. This article focuses on the presentation of BWS as an aid to early detection.

Esophageal atresia and Beckwith-Wiedemann syndrome in one of the naturally conceived discordant newborn twins: first report

Recent studies report a high incidence of monozygotic twinning in Beckwith–Wiedemann syndrome. A phenotypical discordance in monozygotic twins is rare. Twinning and Beckwith–Wiedemann syndrome show higher incidence in children born after assisted reproductive techniques. We report on the first observation of esophageal atresia and Beckwith–Wiedemann syndrome in one of the naturally conceived discordant monozygotic twins.

Assisted Reproductive Techniques and Risk of Beckwith-Wiedemann Syndrome

BACKGROUND AND OBJECTIVES

The emerging association of assisted reproductive techniques (ART) with imprinting disorders represents a major issue in the scientific debate on infertility treatment and human procreation. We studied the prevalence of Beckwith-Wiedemann syndrome (BWS) in children conceived through ART to define the specific associated relative risk.

METHODS

Patients with BWS born in Piemonte, Italy, were identified and matched with the general demographic data and corresponding regional ART registry.

RESULTS

Between 2005 and 2014, live births in Piemonte were 379 872, including 7884 from ART. Thirty-eight patients with BWS were born, 7 from ART and 31 naturally conceived. BWS birth prevalence in the ART group was significantly higher than that of the naturally conceived group (1:1126 vs 1:12 254, P < .001). The absolute live birth risk in the ART group was 887.9 per 1 000 000 vs 83.3 per 1 000 000 in the naturally conceived group, providing a relative risk of 10.7 (95% confidence interval 4.7-24.2). During the 1997-2014 period, 67 patients were diagnosed with BWS out of 663 834 newborns (1:9908 live births). Nine out of the 67 BWS patients were conceived through ART (13.4%), and 8 were molecularly tested, with 4 having an imprinting center 2 loss of methylation, 2 with 11p15.5 paternal uniparental disomy, and 2 negative results.

CONCLUSIONS

ART entails a 10-fold increased risk of BWS and could be implicated in the pathogenesis of genomic events besides methylation anomalies. These data highlight the need for awareness of ART-associated health risk.

The utility of alpha-fetoprotein screening in Beckwith-Wiedemann syndrome

Beckwith-Wiedemann syndrome (BWS) is one of the most common cancer predisposition disorders. As a result, BWS patients receive tumor screening as part of their clinical management. Until recently, this screening has been employed uniformly across all genetic and epigenetic causes of BWS, including the utilization of ultrasonography to detect abdominal tumors and alpha-fetoprotein (AFP) to detect hepatoblastoma. The advancements in our understanding of the genetics and epigenetics leading to BWS has evolved over time, and has led to the development of genotype/phenotype correlations. As tumor risk appears to correlate with genetic and epigenetic causes of BWS, several groups have proposed alterations to tumor screening protocols based on the etiology of BWS, with the elimination of AFP as a screening measure and the elimination of all screening measures in BWS patients with loss of methylation at the KCNQ1OT1:TSS-DMR 2 (IC2). There are many challenges to this suggestion, as IC2 patients may have additional factors that contribute to risk of hepatoblastoma including fetal growth patterns, relationship with assisted reproductive technologies, and the regulation of the IC2 locus. © 2017 Wiley Periodicals, Inc.

Clinical and molecular characterization of Beckwith-Wiedemann syndrome in a Chinese population

BACKGROUND

The objective of this study was to examine the clinical and molecular features, genotype-phenotype correlation and the efficacy of different diagnostic criteria for predicting a positive molecular test in Chinese Beckwith-Wiedemann syndrome (BWS) patients.

METHODS

A retrospective tertiary-wide study was performed in Hong Kong with 27 molecularly confirmed BWS patients between January 2010 and September 2015.

RESULTS

It was observed that 48.1% of the BWS cases were caused by loss of methylation at differentially methylated region 2 (DMR2-LoM) of the 11p15.5 region, 11.1% by gain of methylation at differentially methylated region 1 (DMR1-GoM) of the 11p15.5 region, 33.3% by paternal uniparental disomy 11 [upd (11)pat] and 7.5% by CDKN1C mutation. Two out of 27 (7.4%) had embryonal tumors. Both belonged to the DMR1-GoM subtype with one Wilm's tumor diagnosed at 3 months of age and the other, hepatoblastoma, diagnosed at 6 months of age. However, no genotype-phenotype correlation can be concluded by this cohort study. Finally, for different clinical diagnostic criteria, the Debaun and Tucker criteria and the Ibrahim et al. weighing score system have the best performance for predicting a positive molecular test in our Chinese BWS cohort.

CONCLUSIONS

It is the largest study of molecularly confirmed BWS in the Chinese. Their clinical and epigenetic features are comparable with other ethnic populations.

Epigenotype, genotype, and phenotype analysis of patients in Taiwan with Beckwith-Wiedemann syndrome

BACKGROUND

Beckwith-Wiedemann syndrome (BWS) is a congenital overgrowth disorder predisposing to tumorigenesis that results from abnormal expression or function of imprinted genes of chromosome 11p15.5.

METHODS

Forty-seven patients in Taiwan with clinical suspicion of BWS were referred for diagnostic testing based on methylation profiling of H19-associated imprinting center (IC) 1 and KCNQ1OT1-associated IC2 using high-resolution melting analysis, multiplex ligation-dependent probe amplification, or high-resolution quantitative methylation profiling.

RESULTS

Twenty-eight patients received a clinical diagnosis of BWS (the presence of 3 major features or 2 major features and at least 1 minor feature), 18 had suspected BWS (the presence of at least 1 major feature), and 1 had isolated Wilms' tumor. Nineteen patients were identified with IC2 hypomethylation (including 1 with isolated Wilms' tumor), 1 with IC1 hypermethylation, 2 with paternal uniparental disomy, and 1 with CDKN1C mutation. Several clinical features were found to be statistically different (P<0.05) between the 2 groups-clinical diagnosis of BWS (n=28) or suspected BWS (n=18)-including macroglossia, pre- or postnatal gigantism, abdominal wall defect, ear creases, facial nevus flammeus, BWS score, and the molecular diagnosis rate. Molecular lesion was detected in 81% of patients with the presence of three major features, compared with 33% and 28% of those with two or one major feature, respectively. The mean BWS score was 5.6 for 19 subjects with "IC2 hypomethylation", compared with 3.8 for 2 subjects with pUPD. The BWS score of one subject with CDKN1C mutation and one with IC1 hypermethylation was 6 and 7, respectively.

CONCLUSIONS

The BWS score was positively correlated with the molecular diagnosis rate (P<0.01). The BWS database of epigenotype, genotype, and phenotype is expected to promote better genetic counseling and medical care of these patients.