Beckwith-Wiedemann Syndrome Cases Research Articles

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.

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.

EP407: Aberrant KCNQ1 splicing as an emerging mechanism underlying the pathogenesis of familial Beckwith-Wiedemann syndrome with reduced penetrance

Beckwith-Wiedemann Syndrome (BWS) is a phenotypically and genetically heterogeneous congenital imprinting disorder characterized by macroglossia, omphalocele, hemihypertrophy and a predisposition to embryonal tumors. BWS is caused by genetic or epigenetic alterations in the chromosomal region 11p15.5, which consists of genes that are involved in the regulation of cell growth and proliferation. BWS is generally considered a sporadic disease, as approximately 85% of BWS cases occur without family history.

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

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

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

BackgroundBeckwith-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.MethodsPatients 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).ResultsThe 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).ConclusionsThis 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.

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

BackgroundPADI6 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.ResultsWe 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.ConclusionOur 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.

SAT-LB313 A Unicorn With Double Horns - Metastatic Paraganglioma in a Patient With Beckwith-Wiedemann Syndrome and Hereditary Paraganglioma Syndrome Iv

Introduction: Beckwith-Wiedemann syndrome (BWS), a multisystem genomic imprinting disorder in chromosome 11p15.5 region, is an overgrowth syndrome often presenting with macroglossia, abdominal wall defects, hemihyperplasia, enlarged abdominal organs and an increased risk of tumors including neuroblastoma, rhabdomyosarcoma, unilateral Wilm’s tumor, hepatoblastoma, adrenal cortical carcinoma and pheochromocytoma. Six cases of benign bilateral pheochromocytomas and one case of pheochromocytoma with lymph node metastasis in BWS have been described in the literature. We describe the first case of BWS with distant metastatic paraganglioma harboring an SDHB (succinate dehydrogenase subunit B) mutation. Presentation: A 28-year-old male with BWS whose history included an omphalocele and diaphragmatic hernia in infancy, neuroblastoma resected at age 2, and left carotid paraganglioma (PGL) resected at age 22 presented with abdominal pain. CT A/P with contrast revealed a 3.3 x 4.4 cm hypervascular mass and multiple bone metastases. Workup revealed normal plasma/urine metanephrines, elevated plasma dopamine of 178 pg/ml (normal <20) and elevated chromogranin A of 190 ng/ml (normal <90). 68Ga-dotatate PET CT showed hypermetabolic 4.4 cm mass (SUV 83), right hypopharynx mass (SUV 49), and many dota avid areas throughout the skeleton. The abdominal mass was resected and pathology was consistent with PGL. Due to unusual presentation, patient underwent hereditary cancer genetic testing (67 gene panel) and pathogenic mutation (c.713delT) in the SDHB gene was identified, consistent with hereditary PGL syndrome IV. Conclusion: While pheochromocytomas and other tumors are commonly found in association with BWS, PGLs are not. This is the first documented case of a patient with BWS having distant metastatic PGL. Malignant transformation of hereditary and sporadic pheochromocytomas and paraganglioma (PPGLs) is more common in SDHx associated PPGLs (>40% of metastatic PPGLs are related to an SDHB mutation). Hereditary PGL syndromes should be suspected in the case of PGLs that are recurrent, early onset (<45 years), extra-adrenal and/or metastatic. With additional genetic testing, our patient with an already rare growth disorder was found to have hereditary PGL syndrome IV caused by a pathogenic mutation in the SDHB gene. This unique case highlights the rationale and importance of systematic genetic cancer screening in the diagnostic evaluation of PPGLs.

Genetic investigation of patients with tall stature.

Patients with tall stature often remain undiagnosed after clinical investigation and few studies have genetically assessed this group, most of them without a systematic approach. To assess prospectively a group of individuals with tall stature, with and without syndromic features, and to establish a molecular diagnosis for their growth disorder. Screening by karyotype (n = 42), chromosome microarray analyses (CMA) (n = 16), MS-MLPA (n = 2) targeted panel (n = 12) and whole-exome sequencing (n = 31). We selected 42 patients with tall stature after exclusion of pathologies in GH/IGF1 axis and divided them into syndromic (n = 30) and non-syndromic (n = 12) subgroups. Frequencies of pathogenic findings. We identified two patients with chromosomal abnormalities including SHOX trisomy by karyotype, one 9q22.3 microdeletion syndrome by CMA, two cases of Beckwith-Wiedemann syndrome by targeted MS-MLPA analysis and nine cases with heterozygous pathogenic or likely pathogenic genetic variants by multigene analysis techniques (FBN1 = 3, NSD1 = 2, NFIX = 1, SUZ12 = 1, CHD8 = 1, MC4R = 1). Three of 20 patients analyzed by WES had their diagnosis established. Only one non-syndromic patient had a definitive diagnosis. The sequential genetic assessment diagnosed 14 out of 42 (33.3%) tall patients. A systematic molecular approach of patients with tall stature was able to identify the etiology in 13 out of 30 (43.3%) syndromic and 1 out of 12 (8.3%) non-syndromic patients, contributing to the genetic counseling and avoiding unfavorable outcomes in the syndromic subgroup.

Beckwith-Wiedemann Syndrome: A Case Report at the Gynaeco-Obstetric and Pediatric Hospital in Yaounde, Cameroon

Beckwith-Wiedemann syndrome is a rare congenital syndrome, but one of the most common among overgrowth syndromes. It was described firstly by Beckwith in 1963. The incidence of BWS is about 1:13 700 births, with an equal sex distribution. It is characterized by macrosomia, macroglossia, omphalocele and anterior abdominal wall defects. It is a complex multigenic disorder caused by dysregulation of the gene printed on chromosome 11p. 15. A relationship has been established between assisted fertilization methods and its occurrence. This syndrome predisposes to childhood cancer. Its incidence is not known in developing countries such as Cameroon due to the rarity of reported cases, variability in the presentation of the syndrome, financial constraints and lack of access to genetic and molecular studies. In our opinion, we are reporting the first case of Beckwith-Wiedemann syndrome in our country. We present here the case of a newborn female baby delivered at the gyneco-obstetric and pediatric hospital in Yaounde and admitted to our neonatology unit. The diagnosis was made on the basis of clinical signs suggestive of Beckwith-Wiedemann syndrome. She presented an omphalocele diagnosed on antenatal ultrasound, macrosomia, macroglossia and ear abnormalities. The case is presented to raise awareness and highlight the particularity of the management of this rare disease.

A rare case of Beckwith-Wiedemann syndrome with encephalocele.

Image in medicine A premature female child was delivered with polyhydramnios, an unusually large placenta and long umbilical cord. The clinical examination revealed that there is macrosomia, macroglossia and encephalocele. The patient also had complains of hypoglycemia on 2nd day and on the clinical examination, the patient was diagnosed with a rare case of Beckwith-Wiedemann Syndrome with encephalocele. Figure 1 A) anterior view with macroglossia and macrosomia; B) posterior view with encephalocele

Rare clinical findings in three sporadic cases of Beckwith-Wiedemann syndrome due to novel mutations in the CDKN1C gene.

Beckwith-Wiedemann syndrome (BWS) is a rare congenital overgrowth disorder characterised by macroglossia, abdominal wall defects, neonatal hypoglycaemia, lateralised overgrowth and predisposition to embryonal tumours. BWS results mainly from epigenetic changes at chromosome 11p15.5; however, heterozygous pathogenic variants on the maternal CDKN1C allele are observed in 5-8% of sporadic BWS cases. In this study, we report three sporadic BWS patients with novel pathogenic variants in the CDKN1C gene, including one missense (c.181T>C) and two frameshift (c.415_416dup, c.804delC). Detailed clinical evaluation of the patients showed variable manifestation of the disease and underlined the diagnostic challenge for BWS patients at various age of life. The child with the c.415_416dup variant presented with two rare features observed so far in only a few BWS patients with CDKN1C pathogenic variants: supernumerary flexion creases and agenesis of corpus callosum. Confirmation of these findings in another BWS patient adds to the broad clinical spectrum of the disease and suggests that presence of these features may be associated with CDKN1C pathogenic variants.

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.

Fetal growth restriction in a genetic model of sporadic Beckwith-Wiedemann syndrome.

ABSTRACTBeckwith–Wiedemann syndrome (BWS) is a complex imprinting disorder involving fetal overgrowth and placentomegaly, and is associated with a variety of genetic and epigenetic mutations affecting the expression of imprinted genes on human chromosome 11p15.5. Most BWS cases are linked to loss of methylation at the imprint control region 2 (ICR2) within this domain, which in mice regulates the silencing of several maternally expressed imprinted genes. Modelling this disorder in mice is confounded by the unique embryonic requirement for Ascl2, which is imprinted in mice but not in humans. To overcome this issue, we generated a novel model combining a truncation of distal chromosome 7 allele (DelTel7) with transgenic rescue of Ascl2 expression. This novel model recapitulated placentomegaly associated with BWS, but did not lead to fetal overgrowth.

Diagnostic anténatal des anomalies de la paroi abdominale antérieure

Anterior abdominal wall defects (AAWD) correspond to a wide spectrum of congenital defects affecting 6.3/10,000 pregnancies. They have in common a closure defect of the anterior abdominal wall and can be fatal or expose the fetus and the neonate (NN) to many complications. This study was based on a retrospective study of 22 cases of AAWD collected between May 2009 and December 2014. Its purpose was to specify the importance of prenatal ultrasonography in the diagnosis and prognosis assessment of these defects. These 22 AAWDs consisted in 13 cases of omphalocele (including four cases of Beckwith-Wiedemann syndrome), four of gastroschisis, one of pentalogy of Cantrell, three of vesical exstrophy and one of cloacal exstrophy. Prenatal ultrasonography provided the diagnosis of 14 of these defects with a changing sensitivity with the gestational age varying from 17% in the first trimester to 71.4% and 77.8% in the second and third trimesters, respectively. The relevance of this examination was improved when performed by an imaging specialist. The prenatal diagnosis of these defects indicated an amniocentesis in eight cases, allowing the diagnosis of two cases of trisomy 18. It also motivated a therapeutic termination of the pregnancy (TTP) in ten cases. Prenatal ultrasonography allowed better prenatal follow-up and planning of the delivery of the continued pregnancies. It indicated an emergency C-section in only one case by showing intestinal complications of gastroschisis. Four NNs died (two cases of omphalocele and two of gastroschisis), three of which postoperatively and the prenatal diagnosis did not improve survival. Prenatal ultrasonographic diagnosis provided a precise morphological study determining the type of the AAWD, a complete malformation assessment, and the prognosis factors. This resulted in adequate multidisciplinary pre and postnatal care, including a rigorous ultrasound follow-up, a TTP in case of associated defects, and emergency delivery once the complications of poor diagnosis are detected.

Blocked transcription through KvDMR1 results in absence of methylation and gene silencing resembling Beckwith-Wiedemann syndrome.

The maternally methylated KvDMR1 ICR regulates imprinted expression of a cluster of maternally expressed genes on human chromosome 11p15.5. Disruption of imprinting leads to Beckwith-Wiedemann syndrome (BWS), an overgrowth and cancer predisposition condition. In the majority of individuals with BWS, maternal-specific methylation at KvDMR1 is absent and genes under its control are repressed. We analyzed a mouse model carrying a poly(A) truncation cassette inserted to prevent RNA transcripts from elongation through KvDMR1. Maternal inheritance of this mutation resulted in absence of DNA methylation at KvDMR1, which led to biallelic expression of Kcnq1ot1 and suppression of maternally expressed genes. This study provides further evidence that transcription is required for establishment of methylation at maternal gametic DMRs. More importantly, this mouse model recapitulates the molecular phenotypic characteristics of the most common form of BWS, including loss of methylation at KvDMR1 and biallelic repression of Cdkn1c, suggesting that deficiency of maternal transcription through KvDMR1 may be an underlying cause of some BWS cases.

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

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. A retrospective tertiary-wide study was performed in Hong Kong with 27 molecularly confirmed BWS patients between January 2010 and September 2015. 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. It is the largest study of molecularly confirmed BWS in the Chinese. Their clinical and epigenetic features are comparable with other ethnic populations.

Mutations of the Imprinted CDKN1C Gene as a Cause of the Overgrowth Beckwith-Wiedemann Syndrome: Clinical Spectrum and Functional Characterization.

Beckwith-Wiedemann syndrome (BWS) is an imprinting disorder associating macroglossia, abdominal wall defects, visceromegaly, and a high risk of childhood tumor. Molecular anomalies are mostly epigenetic; however, mutations of CDKN1C are implicated in 8% of cases, including both sporadic and familial forms. We aimed to describe the phenotype of BWS patients with CDKN1C mutations and develop a functional test for CDKN1C mutations. For each propositus, we sequenced the three exons and intron-exon boundaries of CDKN1C in patients presenting a BWS phenotype, including abdominal wall defects, without 11p15 methylation defects. We developed a functional test based on flow cytometry. We identified 37 mutations in 38 pedigrees (50 patients and seven fetuses). Analysis of parental samples when available showed that all mutations tested but one was inherited from the mother. The four missense mutations led to a less severe phenotype (lower frequency of exomphalos) than the other 33 mutations. The following four tumors occurred: one neuroblastoma, one ganglioneuroblastoma, one melanoma, and one acute lymphoid leukemia. Cases of BWS caused by CDKN1C mutations are not rare. CDKN1C sequencing should be performed for BWS patients presenting with abdominal wall defects or cleft palate without 11p15 methylation defects or body asymmetry, or in familial cases of BWS.

High frequency of copy number variations (CNVs) in the chromosome 11p15 region in patients with Beckwith–Wiedemann syndrome

Beckwith-Wiedemann syndrome (BWS), an overgrowth and tumor predisposition syndrome is clinically heterogeneous. Its variable presentation makes molecular diagnosis particularly important for appropriate counseling of patients with respect to embyronal tumor risk and recurrence risk. BWS is characterized by macrosomia, omphalocele, and macroglossia. Additional clinical features can include hemihyperplasia, embryonal tumors, umbilical hernia, and ear anomalies. BWS is etiologically heterogeneous arising from dysregulation of one or both of the chromosome 11p15.5 imprinting centers (IC) and/or imprinted growth regulatory genes on chromosome 11p15.5. Most BWS cases are sporadic and result from loss of maternal methylation at imprinting center 2 (IC2), gain of maternal methylation at imprinting center 1 (IC1) or paternal uniparental disomy (UPD). Heritable forms of BWS (15 %) have been attributed mainly to mutations in the growth suppressor gene CDKN1C, but have also infrequently been identified in patients with copy number variations (CNVs) in the chromosome 11p15.5 region. Four hundred and thirty-four unrelated BWS patients referred to the molecular diagnostic laboratory were tested by methylation-specific multiplex ligation-dependent probe amplification. Molecular alterations were detected in 167 patients, where 103 (62 %) showed loss of methylation at IC2, 23 (14 %) had gain of methylation at IC1, and 41 (25 %) showed changes at both ICs usually associated with paternal UPD. In each of the three groups, we identified patients in whom the abnormalities in the chromosome 11p15.5 region were due to CNVs. Surprisingly, 14 patients (9 %) demonstrated either deletions or duplications of the BWS critical region that were confirmed using comparative genomic hybridization array analysis. The majority of these CNVs were associated with a methylation change at IC1. Our results suggest that CNVs in the 11p15.5 region contribute significantly to the etiology of BWS. We highlight the importance of performing deletion/duplication testing in addition to methylation analysis in the molecular investigation of BWS to improve our understanding of the molecular basis of this disorder, and to provide accurate genetic counseling.

Neonatal urethral polyps associated with Beckwith–Wiedemann syndrome

We report the first case of Beckwith-Wiedemann syndrome without urinary obstruction, but with a congenital urethral polyp as a tumor protruding from the external urinary meatus. The present case suggests a possible relation between Beckwith-Wiedemann and the onset of fibroepithelial polyps in the reno-urinary system during the neonatal period.

A time stamp comparative analysis of frequent chromosomal abnormalities in Romanian patients

Chromosome abnormalities represent the leading cause in many human genetic disorders. Gain or loss of genetic material can disrupt the normal expression of genes important in fetal development and result in abnormal phenotypes. Approximately 60% of first-trimester spontaneous abortions exhibit karyotype abnormalities. The majority of these abnormalities consist of numerical chromosomal changes, such as autosomal trisomy, monosomy X and polyploidy. In our current study, 411 cases were analyzed over a period of 5 years, which reflected the incidence of cytogenetic abnormalities in Romania. Down syndrome showed the highest frequency at 79%. At 2.6% structural chromosome abnormality syndromes and Turner syndrome followed suit. Next were the Edwards and Patau syndromes with an incidence of 1.2%. Klinefelter, Cri du chat and Wolf-Hirschhorn syndromes all had an incidence of 0.7%. Finally, the lowest frequencies were shown by Williams at 0.4% and only one case of Beckwith-Wiedemann syndrome with abnormal karyotype. The average maternal age at childbirth was 31.15 years (SD = 6.96) and the average paternal age was 33.41 years (SD = 7.17).