Beckwith-Wiedemann Syndrome

Overview

Overview: Beckwith-Wiedemann Syndrome (BWS) is a growth regulation disorder characterised by macrosomia (large body size) , macroglossia (large tongue), hemihyperplasia (some parts of the body are larger on one side) and kidney abnormalities - often diagnosed at birth. Children with BWS have an increased risk of developing childhood tumors (estimated at 7.5% of cases), usually before age 10: Wilms Tumor, Hepatoblastoma, Adrenocortical carcinoma, Rhabdomyosarcoma, and Neuroblastoma.

BWS is linked to genetic and epigenetic abnormalities of an area of chromosome 11 (11p15.5), which includes the CDKN1C and IGF2 genes. Most cases of BWS (about 85%) are sporadic (non-inherited, occurring by chance). Some cases of BWS (between 10-15%) are inherited in an autosomal dominant pattern. Overall incidence is estimated to be 1 out of 13,700 population (Weksberg et al, 2010).

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Translocation
  • Gene Deletion
  • Chromosome Mapping
  • Phenotype
  • Pregnancy Complications
  • Membrane Proteins
  • Infant
  • Chromosome 11
  • Childhood Cancer
  • Long Noncoding RNA
  • RNA, Untranslated
  • Mutation
  • Pedigree
  • Genomic Imprinting
  • Zinc Fingers
  • Potassium Channels, Voltage-Gated
  • Liver Cancer
  • DNA Methylation
  • KCNQ Potassium Channels
  • Potassium Channels
  • Chromosome Aberrations
  • IGF2
  • Newborns
  • Base Sequence
  • Uniparental Disomy
  • Trisomy
  • Molecular Sequence Data
  • Rhabdomyosarcoma
  • Nuclear Proteins
  • Kidney Cancer
  • Pregnancy
  • Genetic Predisposition
  • Genotype
  • Telomere
  • Alleles
  • Repressor Proteins
  • Beckwith-Wiedemann syndrome
  • Cyclin-Dependent Kinase Inhibitor p57
  • Chromosome Deletion
Tag cloud generated 10 March, 2017 using data from PubMed, MeSH and CancerIndex

Mutated Genes and Abnormal Protein Expression (6)

How to use this data tableClicking on the Gene or Topic will take you to a separate more detailed page. Sort this list by clicking on a column heading e.g. 'Gene' or 'Topic'.

GeneLocationAliasesNotesTopicPapers
IGF2 11p15.5 GRDF, IGF-II, PP9974, C11orf43 Epigenetics
-IGF2 and Beckwith-Wiedemann Syndrome
116
CDKN1C 11p15.4 BWS, WBS, p57, BWCR, KIP2, p57Kip2 -CDKN1C and Beckwith-Wiedemann syndrome
18
KCNQ1OT1 11p15.5 LIT1, Kncq1, KvDMR1, KCNQ10T1, KCNQ1-AS2, KvLQT1-AS, NCRNA00012 -KCNQ1OT1 and Beckwith-Wiedemann syndrome
14
WT2 11p15.5 ADCR, MTACR1 -WT2 and Beckwith-Wiedemann syndrome
7
KCNQ1 11p15.5-p15.4 LQT, RWS, WRS, LQT1, SQT2, ATFB1, ATFB3, JLNS1, KCNA8, KCNA9, Kv1.9, Kv7.1, KVLQT1 -KCNQ1 and Beckwith-Wiedemann syndrome
7
SLC22A18 11p15.4 HET, ITM, BWR1A, IMPT1, TSSC5, ORCTL2, BWSCR1A, SLC22A1L, p45-BWR1A -SLC22A18 and Beckwith-Wiedemann syndrome
2

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Useful Links (7 links)

Latest Publications

Khoshnam N, Robinson H, Clay MR, et al.
Calcifying nested stromal-epithelial tumor (CNSET) of the liver in Beckwith-Wiedemann syndrome.
Eur J Med Genet. 2017; 60(2):136-139 [PubMed] Related Publications
Calcifying nested stromal-epithelial tumor (CNSET) is a rare neoplasm. In the 31 reported cases, CNSET is predominantly found in young girls and women. Beckwith-Wiedemann syndrome (BWS) (OMIM #130650) is an overgrowth syndrome with an increased risk to develop cancer. Associations have been seen between BWS and embryonal tumors, especially Wilms tumor, hepatoblastoma, and adrenocortical carcinoma. Here we report on a female patient with BWS who presented with CNSET. Two other cases with the same association have been reported, with our case representing the third such reported in the literature. Although we recognize a potential reporting bias we speculate that CNSET may represent an unrecognized addition to the spectrum of BWS tumorigenesis.

Russo S, Calzari L, Mussa A, et al.
A multi-method approach to the molecular diagnosis of overt and borderline 11p15.5 defects underlying Silver-Russell and Beckwith-Wiedemann syndromes.
Clin Epigenetics. 2016; 8:23 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Multiple (epi)genetic defects affecting the expression of the imprinted genes within the 11p15.5 chromosomal region underlie Silver-Russell (SRS) and Beckwith-Wiedemann (BWS) syndromes. The molecular diagnosis of these opposite growth disorders requires a multi-approach flowchart to disclose known primary and secondary (epi)genetic alterations; however, up to 20 and 30 % of clinically diagnosed BWS and SRS cases remain without molecular diagnosis. The complex structure of the 11p15 region with variable CpG methylation and low-rate mosaicism may account for missed diagnoses. Here, we demonstrate the relevance of complementary techniques for the assessment of different CpGs and the importance of testing multiple tissues to increase the SRS and BWS detection rate.
RESULTS: Molecular testing of 147 and 450 clinically diagnosed SRS and BWS cases provided diagnosis in 34 SRS and 185 BWS patients, with 9 SRS and 21 BWS cases remaining undiagnosed and herein referred to as "borderline." A flowchart including complementary techniques and, when applicable, the analysis of buccal swabs, allowed confirmation of the molecular diagnosis in all borderline cases. Comparison of methylation levels by methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) in borderline and control cases defined an interval of H19/IGF2:IG-DMR loss of methylation that was distinct between "easy to diagnose" and "borderline" cases, which were characterized by values ≤mean -3 standard deviations (SDs) compared to controls. Values ≥mean +1 SD at H19/IGF2: IG-DMR were assigned to borderline hypermethylated BWS cases and those ≤mean -2 SD at KCNQ1OT1: TSS-DMR to hypomethylated BWS cases; these were supported by quantitative pyrosequencing or Southern blot analysis. Six BWS cases suspected to carry mosaic paternal uniparental disomy of chromosome 11 were confirmed by SNP array, which detected mosaicism till 10 %. Regarding the clinical presentation, borderline SRS were representative of the syndromic phenotype, with exception of one patient, whereas BWS cases showed low frequency of the most common features except hemihyperplasia.
CONCLUSIONS: A conclusive molecular diagnosis was reached in borderline methylation cases, increasing the detection rate by 6 % for SRS and 5 % for BWS cases. The introduction of complementary techniques and additional tissue analyses into routine diagnostic work-up should facilitate the identification of cases undiagnosed because of mosaicism, a distinctive feature of epigenetic disorders.

Chen J, Yao ZX, Chen JS, et al.
TGF-β/β2-spectrin/CTCF-regulated tumor suppression in human stem cell disorder Beckwith-Wiedemann syndrome.
J Clin Invest. 2016; 126(2):527-42 [PubMed] Free Access to Full Article Related Publications
Beckwith-Wiedemann syndrome (BWS) is a human stem cell disorder, and individuals with this disease have a substantially increased risk (~800-fold) of developing tumors. Epigenetic silencing of β2-spectrin (β2SP, encoded by SPTBN1), a SMAD adaptor for TGF-β signaling, is causally associated with BWS; however, a role of TGF-β deficiency in BWS-associated neoplastic transformation is unexplored. Here, we have reported that double-heterozygous Sptbn1+/- Smad3+/- mice, which have defective TGF-β signaling, develop multiple tumors that are phenotypically similar to those of BWS patients. Moreover, tumorigenesis-associated genes IGF2 and telomerase reverse transcriptase (TERT) were overexpressed in fibroblasts from BWS patients and TGF-β-defective mice. We further determined that chromatin insulator CCCTC-binding factor (CTCF) is TGF-β inducible and facilitates TGF-β-mediated repression of TERT transcription via interactions with β2SP and SMAD3. This regulation was abrogated in TGF-β-defective mice and BWS, resulting in TERT overexpression. Imprinting of the IGF2/H19 locus and the CDKN1C/KCNQ1 locus on chromosome 11p15.5 is mediated by CTCF, and this regulation is lost in BWS, leading to aberrant overexpression of growth-promoting genes. Therefore, we propose that loss of CTCF-dependent imprinting of tumor-promoting genes, such as IGF2 and TERT, results from a defective TGF-β pathway and is responsible at least in part for BWS-associated tumorigenesis as well as sporadic human cancers that are frequently associated with SPTBN1 and SMAD3 mutations.

Wofford J, Fenves AZ, Jackson JM, et al.
The spectrum of nephrocutaneous diseases and associations: Genetic causes of nephrocutaneous disease.
J Am Acad Dermatol. 2016; 74(2):231-44; quiz 245-6 [PubMed] Related Publications
There are a significant number of diseases and treatment considerations of considerable importance relating to the skin and renal systems. This emphasizes the need for dermatologists in practice or in clinical training to be aware of these associations. Part I of this 2-part continuing medical education article reviews the genetic syndromes with both renal and cutaneous involvement that are most important for the dermatologist to be able to identify, manage, and appropriately refer to nephrology colleagues. Part II reviews the inflammatory syndromes with relevant renal manifestations and therapeutic agents commonly used by dermatologists that have drug-induced effects on or require close consideration of renal function. In addition, we will likewise review therapeutic agents commonly used by nephrologists that have drug-induced effects on the skin that dermatologists are likely to encounter in clinical practice. In both parts of this continuing medical education article, we discuss diagnosis, management, and appropriate referral to our nephrology colleagues in the context of each nephrocutaneous association. There are a significant number of dermatoses associated with renal abnormalities and disease, emphasizing the need for dermatologists to be keenly aware of their presence in order to avoid overlooking important skin conditions with potentially devastating renal complications. This review discusses important nephrocutaneous disease associations with recommendations for the appropriate urgency of referral to nephrology colleagues for diagnosis, surveillance, and early management of potential renal sequelae.

Yu B, Zhou H, Liu M, et al.
Epigenetic Alterations in Density Selected Human Spermatozoa for Assisted Reproduction.
PLoS One. 2015; 10(12):e0145585 [PubMed] Free Access to Full Article Related Publications
Epidemiological evidence indicates that assisted reproductive technologies (ART) may be associated with several epigenetic diseases such as Beckwith-Wiedemann syndrome (BWS) or Silver-Russell syndrome (SRS). Selection of sperm by density-gradients in ART has improved DNA integrity and sperm quality; however, epigenetic alterations associated with this approach are largely unknown. In the present study, we investigated DNA methylation and histone retention profiles in raw sperm and selected sperm derived from the same individual and separated by using density-gradients. Results from a study group consisting of 93 males demonstrated that both global DNA methylation and histone retention levels decreased in density selected sperm. Compared to unselected raw sperm, histone transition rates decreased by an average of 27.2% in selected sperm, and the global methylation rate was 3.8% in unselected sperm and 3.3% in the selected sperm. DNA methylation and histone retention location profiling analyses suggested that these alterations displayed specific location patterns in the human genome. Changes in the pattern of hypomethylation largely occurred in transcriptional factor gene families such as HOX, FOX, and GATA. Histone retention increased in 67 genes, whereas it was significantly clustered in neural development-related gene families, particularly the olfactory sensor gene family. Although a causative relationship could not be established, the results of the present study suggest the possibility that sperm with good density also possess unique epigenetic profiles, particularly for genes involved in neural and olfactory development. As increasing evidence demonstrates that epigenetics plays a key role in embryonic development and offspring growth characteristics, the specific epigenetic alterations we observed in selected sperm may influence the transcriptional process and neural development in embryos.

Mussa A, Di Candia S, Russo S, et al.
Recommendations of the Scientific Committee of the Italian Beckwith-Wiedemann Syndrome Association on the diagnosis, management and follow-up of the syndrome.
Eur J Med Genet. 2016; 59(1):52-64 [PubMed] Related Publications
UNLABELLED: Beckwith-Wiedemann syndrome (BWS) is the most common (epi)genetic overgrowth-cancer predisposition disorder. Given the absence of consensual recommendations or international guidelines, the Scientific Committee of the Italian BWS Association (www.aibws.org) proposed these recommendations for the diagnosis, molecular testing, clinical management, follow-up and tumor surveillance of patients with BWS. The recommendations are intended to allow a timely and appropriate diagnosis of the disorder, to assist patients and their families, to provide clinicians and caregivers optimal strategies for an adequate and satisfactory care, aiming also at standardizing clinical practice as a national uniform approach. They also highlight the direction of future research studies in this setting. With recent advances in understanding the disease (epi)genetic mechanisms and in describing large cohorts of BWS patients, the natural history of the disease will be dissected. In the era of personalized medicine, the emergence of specific (epi)genotype-phenotype correlations in BWS will likely lead to differentiated follow-up approaches for the molecular subgroups, to the development of novel tools to evaluate the likelihood of cancer development and to the refinement and optimization of current tumor screening strategies.
CONCLUSIONS: In this article, we provide the first comprehensive recommendations on the complex management of patients with Beckwith-Wiedemann syndrome.

Gripp KW, Robbins KM, Sheffield BS, et al.
Paternal uniparental disomy 11p15.5 in the pancreatic nodule of an infant with Costello syndrome: Shared mechanism for hyperinsulinemic hypoglycemia in neonates with Costello and Beckwith-Wiedemann syndrome and somatic loss of heterozygosity in Costello syndrome driving clonal expansion.
Am J Med Genet A. 2016; 170(3):559-64 [PubMed] Free Access to Full Article Related Publications
Costello syndrome (CS) entails a cancer predisposition and is caused by activating HRAS mutations, typically arising de novo in the paternal germline. Hypoglycemia is common in CS neonates. A previously reported individual with the rare HRAS p.Gln22Lys had hyperinsulinemic hypoglycemia. Autopsy showed a discrete pancreatic nodule. The morphologic and immunohistochemistry findings, including loss of p57(Kip2) protein, were identical to a focal lesion of congenital hyperinsulinism, however, no KCNJ11 or ABCC8 mutation was identified and germline derived DNA showed no alternation of the maternal or paternal 11p15 alleles. Here we report paternal uniparental disomy (pUPD) within the lesion, similar to the pUPD11p15.5 in Beckwith-Wiedemann syndrome (BWS). The similar extent of the pUPD suggests a similar mechanism driving hyperinsulinemia in both conditions. After coincidental somatic LOH and pUPD, the growth promoting effects of the paternally derived HRAS mutation, in combination with the increased function of the adjacent paternally expressed IGF2, may together result in clonal expansion. Although this somatic LOH within pancreatic tissue resulted in hyperinsulinism, similar LOH in mesenchymal cells may drive embryonal rhabdomyosarcoma (ERMS). Interestingly, biallelic IGF2 expression has been linked to rhabdomyosarcoma tumorigenesis and pUPD11 occurred in all 8 ERMS samples from CS individuals. Somatic KRAS and HRAS mutations occur with comparable frequency in isolated malignancies. Yet, the malignancy risk in CS is notably higher than in Noonan syndrome with a KRAS mutation. It is conceivable that HRAS co-localization with IGF2 and the combined effect of pUPD 11p15.5 on both genes contributes to the oncogenic potential.

Kalish JM, Boodhansingh KE, Bhatti TR, et al.
Congenital hyperinsulinism in children with paternal 11p uniparental isodisomy and Beckwith-Wiedemann syndrome.
J Med Genet. 2016; 53(1):53-61 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Congenital hyperinsulinism (HI) can have monogenic or syndromic causes. Although HI has long been recognised to be common in children with Beckwith-Wiedemann syndrome (BWS), the underlying mechanism is not known.
METHODS: We characterised the clinical features of children with both HI and BWS/11p overgrowth spectrum, evaluated the contribution of KATP channel mutations to the molecular pathogenesis of their HI and assessed molecular pathogenesis associated with features of BWS.
RESULTS: We identified 28 children with HI and BWS/11p overgrowth from 1997 to 2014. Mosaic paternal uniparental isodisomy for chromosome 11p (pUPD11p) was noted in 26/28 cases. Most were refractory to diazoxide treatment and half required subtotal pancreatectomies. Patients displayed a wide range of clinical features from classical BWS to only mild hemihypertrophy (11p overgrowth spectrum). Four of the cases had a paternally transmitted KATP mutation and had a much more severe HI course than patients with pUPD11p alone.
CONCLUSIONS: We found that patients with pUPD11p-associated HI have a persistent and severe HI phenotype compared with transient hypoglycaemia of BWS/11p overgrowth patients caused by other aetiologies. Testing for pUPD11p should be considered in all patients with persistent congenital HI, especially for those without an identified HI gene mutation.

Vals MA, Yakoreva M, Kahre T, et al.
The Frequency of Methylation Abnormalities Among Estonian Patients Selected by Clinical Diagnostic Scoring Systems for Silver-Russell Syndrome and Beckwith-Wiedemann Syndrome.
Genet Test Mol Biomarkers. 2015; 19(12):684-91 [PubMed] Free Access to Full Article Related Publications
AIMS: To study the frequency of methylation abnormalities among Estonian patients selected according to published clinical diagnostic scoring systems for Silver-Russell syndrome (SRS) and Beckwith-Wiedemann syndrome (BWS).
MATERIALS AND METHODS: Forty-eight patients with clinical suspicion of SRS (n = 20) or BWS (n = 28) were included in the study group, to whom methylation-specific multiplex ligation-dependant probe amplification analysis of 11p15 region was made. In addition, to patients with minimal diagnostic score for either SRS or BWS, multilocus methylation-specific single nucleotide primer extension assay was performed.
RESULTS: Five (38%) SRS patients with positive clinical scoring had abnormal methylation pattern at chromosome 11p15, whereas in the BWS group, only one patient was diagnosed with imprinting control region 2 (ICR2) hypomethylation (8%). An unexpected hypomethylation of the PLAGL1 (6q24) and IGF2R (6q25) genes in the patient with the highest BWS scoring was found.
CONCLUSIONS: Compared to BWS, diagnostic criteria used for selecting SRS patients gave us a similar detection rate of 11p15 imprinting disorders as seen in other studies. A more careful selection of patients with possible BWS should be considered to improve the detection of molecularly confirmed cases. Genome-wide multilocus methylation tests could be used in routine clinical practice as it increases the detection rates of imprinting disorders.

Bakker B, Sonneveld LJ, Woltering MC, et al.
A Girl With Beckwith-Wiedemann Syndrome and Pseudohypoparathyroidism Type 1B Due to Multiple Imprinting Defects.
J Clin Endocrinol Metab. 2015; 100(11):3963-6 [PubMed] Related Publications
CONTEXT: Several patients with Beckwith-Wiedemann Syndrome (BWS) with multiple imprinting defects found by genetic analysis have been described. However, only two cases have been described with both genetic and clinical signs and symptoms of multiple diseases caused by imprinting defects.
CASE DESCRIPTION: The girl in this case presented at the age of 6 months with morbid obesity (body mass index, +7.5 SDS) and a large umbilical hernia. Genetic analysis showed BWS (hypomethylation of the KCNQ1OT1 gene). Calcium homeostasis was normal, and she had no signs of Albright hereditary osteodystrophy. At the age of 10 years, she presented with fatigue, and laboratory analyses showed marked hypocalcemia with signs of PTH resistance, but without evidence for Albright hereditary osteodystrophy, thus suggesting pseudohypoparathyroidism type 1B. Consistent with this diagnosis, methylation analysis of the GNAS complex revealed hypomethylation (about 20%) of the GNAS exon 1A, NESPAS, and GNASXL loci and hypermethylation (100% methylation) of the NESP locus.
CONCLUSIONS: Imprinting defects at several different loci can occur in some patients, thus causing multiple different diseases. Symptoms of pseudohypoparathyroidism type 1B may be absent at diagnosis of BWS, yet prolonged subclinical hypocalcemia and/or hyperphosphatemia can have negative consequences (eg, intracerebral calcifications, myocardial dysfunction). We therefore suggest that patients with an imprinting disorder should be monitored for elevations in PTH, and epigenetic analysis of the GNAS complex locus should be considered.

Docherty LE, Rezwan FI, Poole RL, et al.
Mutations in NLRP5 are associated with reproductive wastage and multilocus imprinting disorders in humans.
Nat Commun. 2015; 6:8086 [PubMed] Free Access to Full Article Related Publications
Human-imprinting disorders are congenital disorders of growth, development and metabolism, associated with disturbance of parent of origin-specific DNA methylation at imprinted loci across the genome. Some imprinting disorders have higher than expected prevalence of monozygotic twinning, of assisted reproductive technology among parents, and of disturbance of multiple imprinted loci, for which few causative trans-acting mutations have been found. Here we report mutations in NLRP5 in five mothers of individuals affected by multilocus imprinting disturbance. Maternal-effect mutations of other human NLRP genes, NLRP7 and NLRP2, cause familial biparental hydatidiform mole and multilocus imprinting disturbance, respectively. Offspring of mothers with NLRP5 mutations have heterogenous clinical and epigenetic features, but cases include a discordant monozygotic twin pair, individuals with idiopathic developmental delay and autism, and families affected by infertility and reproductive wastage. NLRP5 mutations suggest connections between maternal reproductive fitness, early zygotic development and genomic imprinting.

Darcy D, Atwal PS, Angell C, et al.
Mosaic paternal genome-wide uniparental isodisomy with down syndrome.
Am J Med Genet A. 2015; 167A(10):2463-9 [PubMed] Related Publications
We report on a 6-month-old girl with two apparent cell lines; one with trisomy 21, and the other with paternal genome-wide uniparental isodisomy (GWUPiD), identified using single nucleotide polymorphism (SNP) based microarray and microsatellite analysis of polymorphic loci. The patient has Beckwith-Wiedemann syndrome (BWS) due to paternal uniparental disomy (UPD) at chromosome location 11p15 (UPD 11p15), which was confirmed through methylation analysis. Hyperinsulinemic hypoglycemia is present, which is associated with paternal UPD 11p15.5; and she likely has medullary nephrocalcinosis, which is associated with paternal UPD 20, although this was not biochemically confirmed. Angelman syndrome (AS) analysis was negative but this testing is not completely informative; she has no specific features of AS. Clinical features of this patient include: dysmorphic features consistent with trisomy 21, tetralogy of Fallot, hemihypertrophy, swirled skin hyperpigmentation, hepatoblastoma, and Wilms tumor. Her karyotype is 47,XX,+21[19]/46,XX[4], and microarray results suggest that the cell line with trisomy 21 is biparentally inherited and represents 40-50% of the genomic material in the tested specimen. The difference in the level of cytogenetically detected mosaicism versus the level of mosaicism observed via microarray analysis is likely caused by differences in the test methodologies. While a handful of cases of mosaic paternal GWUPiD have been reported, this patient is the only reported case that also involves trisomy 21. Other GWUPiD patients have presented with features associated with multiple imprinted regions, as does our patient.

Liu W, Zhang R, Wei J, et al.
Rapid Diagnosis of Imprinting Disorders Involving Copy Number Variation and Uniparental Disomy Using Genome-Wide SNP Microarrays.
Cytogenet Genome Res. 2015; 146(1):9-18 [PubMed] Related Publications
Imprinting disorders, such as Beckwith-Wiedemann syndrome (BWS), Prader-Willi syndrome (PWS) and Angelman syndrome (AS), can be detected via methylation analysis, methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA), or other methods. In this study, we applied single nucleotide polymorphism (SNP)-based chromosomal microarray analysis to detect copy number variations (CNVs) and uniparental disomy (UPD) events in patients with suspected imprinting disorders. Of 4 patients, 2 had a 5.25-Mb microdeletion in the 15q11.2q13.2 region, 1 had a 38.4-Mb mosaic UPD in the 11p15.4 region, and 1 had a 60-Mb detectable UPD between regions 14q13.2 and 14q32.13. Although the 14q32.2 region was classified as normal by SNP array for the 14q13 UPD patient, it turned out to be a heterodisomic UPD by short tandem repeat marker analysis. MS-MLPA analysis was performed to validate the variations. In conclusion, SNP-based microarray is an efficient alternative method for quickly and precisely diagnosing PWS, AS, BWS, and other imprinted gene-associated disorders when considering aberrations due to CNVs and most types of UPD.

Brioude F, Netchine I, Praz F, et al.
Mutations of the Imprinted CDKN1C Gene as a Cause of the Overgrowth Beckwith-Wiedemann Syndrome: Clinical Spectrum and Functional Characterization.
Hum Mutat. 2015; 36(9):894-902 [PubMed] Related Publications
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.

Paganini L, Carlessi N, Fontana L, et al.
Beckwith-Wiedemann syndrome prenatal diagnosis by methylation analysis in chorionic villi.
Epigenetics. 2015; 10(7):643-9 [PubMed] Free Access to Full Article Related Publications
Beckwith-Wiedemann syndrome (BWS) is an imprinting disorder that can be prenatally suspected or diagnosed based on established clinical guidelines. Molecular confirmation is commonly performed on amniocytes. The possibility to use fresh (CVF) and cultured (CVC) chorionic villi has never been investigated. To verify whether CVF and CVC are reliable sources of DNA to study fetal methylation, we used pyrosequencing to test the methylation level of a number of differentially methylated regions (DMRs) at several imprinted loci (ICR1, ICR2, H19, PWS/AS-ICR, GNASXL, GNAS1A, ZAC/PLAGL1, and MEST) and at non-imprinted MGMT and RASSF1A promoters. We analyzed these regions in 19 healthy pregnancies and highlighted stable methylation levels between CVF and CVC at ICR1, ICR2, GNASXL, PWS/AS-ICR, and MEST. Conversely, the methylation levels at H19 promoter, GNAS1A and ZAC/PLAGL1 were different in CVC compared to fresh CV. We also investigated ICR1 and ICR2 methylation level of CVF/CVC of 2 BWS-suspected fetuses (P1 and P2). P1 showed ICR2 hypomethylation, P2 showed normal methylation at both ICR1 and ICR2. Our findings, although limited to one case of BWS fetus with an imprinting defect, can suggest that ICR1 and ICR2, but not H19, could be reliable targets for prenatal BWS diagnosis by methylation test in CVF and CVC. In addition, PWS/AS-ICR, GNASXL, and MEST, but not GNAS1A and ZAC/PLAGL1, are steadily hemimethylated in CV from healthy pregnancies, independently from culture. Thus, prenatal investigation of genomic imprinting in CV needs to be validated in a locus-specific manner.

Jurkiewicz D, Kugaudo M, Tańska A, et al.
11p15 duplication and 13q34 deletion with Beckwith-Wiedemann syndrome and factor VII deficiency.
Pediatr Int. 2015; 57(3):486-91 [PubMed] Related Publications
Here we report a patient with 11p15.4p15.5 duplication and 13q34 deletion presenting with Beckwith-Wiedemann syndrome (BWS) and moderate deficiency of factor VII (FVII). The duplication was initially diagnosed on methylation-sensitive multiplex ligation-dependent probe amplification. Array comparative genome hybridization confirmed its presence and indicated a 13q34 distal deletion. The patient's clinical symptoms, including developmental delay and facial dysmorphism, were typical of BWS with paternal 11p15 trisomy. Partial 13q monosomy in this patient is associated with moderate deficiency of FVII and may also overlap with a few symptoms of paternal 11p15 trisomy such as developmental delay and some facial features. To our knowledge this is the first report of 11p15.4p15.5 duplication associated with deletion of 13q34 and FVII deficiency. Moreover, this report emphasizes the importance of detailed clinical as well as molecular examinations in patients with BWS features and developmental delay.

Fryssira H, Amenta S, Kanber D, et al.
A novel large deletion of the ICR1 region including H19 and putative enhancer elements.
BMC Med Genet. 2015; 16:30 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Beckwith-Wiedemann syndrome (BWS) is a rare pediatric overgrowth disorder with a variable clinical phenotype caused by deregulation affecting imprinted genes in the chromosomal region 11p15. Alterations of the imprinting control region 1 (ICR1) at the IGF2/H19 locus resulting in biallelic expression of IGF2 and biallelic silencing of H19 account for approximately 10% of patients with BWS. The majority of these patients have epimutations of the ICR1 without detectable DNA sequence changes. Only a few patients were found to have deletions. Most of these deletions are small affecting different parts of the ICR1 differentially methylated region (ICR1-DMR) removing target sequences for CTCF. Only a very few deletions reported so far include the H19 gene in addition to the CTCF binding sites. None of these deletions include IGF2.
CASE PRESENTATION: A male patient was born with hypotonia, facial dysmorphisms and hypoglycemia suggestive of Beckwith-Wiedemann syndrome. Using methylation-specific (MS)-MLPA (Multiplex ligation-dependent probe amplification) we have identified a maternally inherited large deletion of the ICR1 region in a patient and his mother. The deletion results in a variable clinical expression with a classical BWS in the mother and a more severe presentation of BWS in her son. By genome-wide SNP array analysis the deletion was found to span ~100 kb genomic DNA including the ICR1DMR, H19, two adjacent non-imprinted genes and two of three predicted enhancer elements downstream to H19. Methylation analysis by deep bisulfite next generation sequencing revealed hypermethylation of the maternal allele at the IGF2 locus in both, mother and child, although IGF2 is not affected by the deletion.
CONCLUSIONS: We here report on a novel large familial deletion of the ICR1 region in a BWS family. Due to the deletion of the ICR1-DMR CTCF binding cannot take place and the residual enhancer elements have access to the IGF2 promoters. The aberrant methylation (hypermethylation) of the maternal IGF2 allele in both affected family members may reflect the active state of the normally silenced maternal IGF2 copy and can be a consequence of the deletion. The deletion results in a variable clinical phenotype and expression.

Mussa A, Russo S, De Crescenzo A, et al.
(Epi)genotype-phenotype correlations in Beckwith-Wiedemann syndrome.
Eur J Hum Genet. 2016; 24(2):183-90 [PubMed] Free Access to Full Article Related Publications
Beckwith-Wiedemann syndrome (BWS) is characterized by cancer predisposition, overgrowth and highly variable association of macroglossia, abdominal wall defects, nephrourological anomalies, nevus flammeus, ear malformations, hypoglycemia, hemihyperplasia, and organomegaly. BWS molecular defects, causing alteration of expression or activity of the genes regulated by two imprinting centres (IC) in the 11p15 chromosomal region, are also heterogeneous. In this paper we define (epi)genotype-phenotype correlations in molecularly confirmed BWS patients. The characteristics of 318 BWS patients with proven molecular defect were compared among the main four molecular subclasses: IC2 loss of methylation (IC2-LoM, n=190), IC1 gain of methylation (IC1-GoM, n=31), chromosome 11p15 paternal uniparental disomy (UPD, n=87), and cyclin-dependent kinase inhibitor 1C gene (CDKN1C) variants (n=10). A characteristic growth pattern was found in each group; neonatal macrosomia was almost constant in IC1-GoM, postnatal overgrowth in IC2-LoM, and hemihyperplasia more common in UPD (P<0.001). Exomphalos was more common in IC2/CDKN1C patients (P<0.001). Renal defects were typical of UPD/IC1 patients, uretheral malformations of IC1-GoM cases (P<0.001). Ear anomalies and nevus flammeus were associated with IC2/CDKN1C genotype (P<0.001). Macroglossia was less common among UPD patients (P<0.001). Wilms' tumor was associated with IC1-GoM or UPD and never observed in IC2-LoM patients (P<0.001). Hepatoblastoma occurred only in UPD cases. Cancer risk was lower in IC2/CDKN1C, intermediate in UPD, and very high in IC1 cases (P=0.009). In conclusion, (epi)genotype-phenotype correlations define four different phenotypic BWS profiles with some degree of clinical overlap. These observations impact clinical care allowing to move toward (epi) genotype-based follow-up and cancer screening.

Adams DJ, Clark DA
Common genetic and epigenetic syndromes.
Pediatr Clin North Am. 2015; 62(2):411-26 [PubMed] Related Publications
Cytogenetic anomalies should be considered in individuals with multiple congenital anomalies. DNA methylation analysis is the most sensitive initial test in evaluating for Prader-Willi and Angelman syndromes. The timely identification of cytogenetic anomalies allows for prompt initiation of early intervention services to maximize the potential of every individual as they grow older. Although many of these conditions are rare, keeping them in mind can have a profound impact on the clinical course of affected individuals. This article reviews some of the more common genetic syndromes.

Chen Z, Hagen DE, Elsik CG, et al.
Characterization of global loss of imprinting in fetal overgrowth syndrome induced by assisted reproduction.
Proc Natl Acad Sci U S A. 2015; 112(15):4618-23 [PubMed] Free Access to Full Article Related Publications
Embryos generated with the use of assisted reproductive technologies (ART) can develop overgrowth syndromes. In ruminants, the condition is referred to as large offspring syndrome (LOS) and exhibits variable phenotypic abnormalities including overgrowth, enlarged tongue, and abdominal wall defects. These characteristics recapitulate those observed in the human loss-of-imprinting (LOI) overgrowth syndrome Beckwith-Wiedemann (BWS). We have recently shown LOI at the KCNQ1 locus in LOS, the most common epimutation in BWS. Although the first case of ART-induced LOS was reported in 1995, studies have not yet determined the extent of LOI in this condition. Here, we determined allele-specific expression of imprinted genes previously identified in human and/or mouse in day ∼105 Bos taurus indicus × Bos taurus taurus F1 hybrid control and LOS fetuses using RNAseq. Our analysis allowed us to determine the monoallelic expression of 20 genes in tissues of control fetuses. LOS fetuses displayed variable LOI compared with controls. Biallelic expression of imprinted genes in LOS was associated with tissue-specific hypomethylation of the normally methylated parental allele. In addition, a positive correlation was observed between body weight and the number of biallelically expressed imprinted genes in LOS fetuses. Furthermore, not only was there loss of allele-specific expression of imprinted genes in LOS, but also differential transcript amounts of these genes between control and overgrown fetuses. In summary, we characterized previously unidentified imprinted genes in bovines and identified misregulation of imprinting at multiple loci in LOS. We concluded that LOS is a multilocus LOI syndrome, as is BWS.

Kagami M, Kurosawa K, Miyazaki O, et al.
Comprehensive clinical studies in 34 patients with molecularly defined UPD(14)pat and related conditions (Kagami-Ogata syndrome).
Eur J Hum Genet. 2015; 23(11):1488-98 [PubMed] Free Access to Full Article Related Publications
Paternal uniparental disomy 14 (UPD(14)pat) and epimutations and microdeletions affecting the maternally derived 14q32.2 imprinted region lead to a unique constellation of clinical features such as facial abnormalities, small bell-shaped thorax with a coat-hanger appearance of the ribs, abdominal wall defects, placentomegaly, and polyhydramnios. In this study, we performed comprehensive clinical studies in patients with UPD(14)pat (n=23), epimutations (n=5), and microdeletions (n=6), and revealed several notable findings. First, a unique facial appearance with full cheeks and a protruding philtrum and distinctive chest roentgenograms with increased coat-hanger angles to the ribs constituted the pathognomonic features from infancy through childhood. Second, birth size was well preserved, with a median birth length of ±0 SD (range, -1.7 to +3.0 SD) and a median birth weight of +2.3 SD (range, +0.1 to +8.8 SD). Third, developmental delay and/or intellectual disability was invariably present, with a median developmental/intellectual quotient of 55 (range, 29-70). Fourth, hepatoblastoma was identified in three infantile patients (8.8%), and histological examination in two patients showed a poorly differentiated embryonal hepatoblastoma with focal macrotrabecular lesions and well-differentiated hepatoblastoma, respectively. These findings suggest the necessity of an adequate support for developmental delay and periodical screening for hepatoblastoma in the affected patients, and some phenotypic overlap between UPD(14)pat and related conditions and Beckwith-Wiedemann syndrome. On the basis of our previous and present studies that have made a significant contribution to the clarification of underlying (epi)genetic factors and the definition of clinical findings, we propose the name 'Kagami-Ogata syndrome' for UPD(14)pat and related conditions.

Kagan KO, Berg C, Dufke A, et al.
Novel fetal and maternal sonographic findings in confirmed cases of Beckwith-Wiedemann syndrome.
Prenat Diagn. 2015; 35(4):394-9 [PubMed] Related Publications
OBJECTIVE: The objective of the study was to examine the prenatal anomalies in fetuses with Beckwith-Wiedemann syndrome (BWS).
METHODS: The study included a retrospective assessment of 12 pregnancies that were seen at three tertiary referral centres (Universities of Tübingen, Bonn, and Cologne/Germany). The genetic mutation, the results of the second trimester ultrasound examination, and the outcome of the pregnancies are shown. Biometric data were transformed into z-values.
RESULTS: Median gestational age at the time of examination was 22.6 (range 19.0-29.7) weeks of gestation. In all cases, the head circumference (HC) and the femur length (FL) were within the normal range, but the HC-FL ratio was above the 95th centile in 75% of the cases. An exomphalos, macroglossia, and visceromegaly were observed in 67%, 50%, and 83% of the cases, and in 58% and 83%, there were polyhydramnios and placentamegaly respectively. The fetal pancreas was identified in three quarters of the cases. A third of the women had large, overstimulation-like ovaries, although each pregnancy was conceived naturally. In four cases, beta-human chorionic gonadotropin (hCG) levels were measured and mean hCG levels were 498 106 IU/L.
DISCUSSION: Besides exomphalos, BWS should be considered if there is macroglossia, a distinct growth pattern, pancreatic hyperplasia, placentamegaly, and substantially increased levels of beta-hCG. © 2015 John Wiley & Sons, Ltd.

Puumala SE, Hoyme HE
Epigenetics in pediatrics.
Pediatr Rev. 2015; 36(1):14-21 [PubMed] Related Publications
Epigenetic mechanisms are external modifications of DNA that cause changes in gene function and are involved in many diseases. Specific examples of pediatric diseases with a known or suspected epigenetic component include Beckwith-Wiedemann syndrome, childhood leukemia, allergies, asthma, fetal alcohol spectrum disorders, childhood obesity, and type 2 diabetes mellitus. Currently, epigenetically active treatments are being used to treat childhood leukemia. Potential epigenetically active treatments and preventive regimens are under study for other diseases. Pediatricians need to be aware of the epigenetic basis of disease to help inform clinical decision making in the future.

Takama Y, Kubota A, Nakayama M, et al.
Fibroadenoma in Beckwith-Wiedemann syndrome with paternal uniparental disomy of chromosome 11p15.5.
Pediatr Int. 2014; 56(6):931-4 [PubMed] Related Publications
Herein is described a case of breast fibroadenomas in a 16-year-old girl with Beckwith-Wiedemann syndrome (BWS) and uniparental disomy (UPD) of chromosome 11p15.5. She was clinically diagnosed with BWS and direct closure was performed for an omphalocele at birth. Subtotal and 90% pancreatectomy were performed for nesidioblastosis at the ages 2 months and 8 years, respectively. Bilateral multiple breast fibroadenomas were noted at the age of 16 and 17 years. In this case, paternal UPD of chromosome 11p15.5 was identified on microsatellite marker analysis. The relevant imprinted chromosomal region in BWS is 11p15.5, and UPD of chromosome 11p15 is a risk factor for BWS-associated tumorigenicity. Chromosome 11p15.5 consists of imprinting domains of IGF2, the expression of which is associated with the tumorigenesis of various breast cancers. This case suggests that fibroadenomas occurred in association with BWS.

Bertoin F, Letouzé E, Grignani P, et al.
Genome-wide paternal uniparental disomy as a cause of Beckwith-Wiedemann syndrome associated with recurrent virilizing adrenocortical tumors.
Horm Metab Res. 2015; 47(7):497-503 [PubMed] Related Publications
Beckwith-Wiedemann syndrome (BWS) is an overgrowth syndrome characterized by fetal macrosomia, macroglossia, and abdominal wall defects. BWS patients are at risk to develop Wilms tumor, neuroblastoma, hepatoblastoma, and adrenal tumors. A young woman with BWS features, but with inconclusive genetic evidence for the disease, came to clinical observation for signs of virilization at the age of 16 years. An adrenocortical tumor was diagnosed and surgically resected. The tumor underwent 2 local relapses that were also surgically treated. The patient was also operated to remove a breast fibroadenoma. SNP arrays were used to analyze chromosome abnormalities in normal and tumor samples from the patient and her parents. The patient presented genome-wide mosaic paternal uniparental disomy (patUPD) both in the adrenocortical and the breast tumors, with different degrees of loss of heterozygosity (LOH). The more recent relapses of the adrenocortical tumor showed a loss of part of chromosome 17p that was absent in the first tumor. Analysis of a skin biopsy sample also showed mosaic patUPD with partial LOH, while no LOH was detected in leukocyte DNA. This case shows that virilizing adrenocortical tumors may be a clinical feature of patients with BWS. The SNP array technology is useful to diagnose genome-wide patUPD mosaicism in BWS patients with an inconclusive molecular diagnosis and underlines the tumorigenic potential of the absence of the maternal genome combined with an excess of the paternal genome.

Eggermann T, Binder G, Brioude F, et al.
CDKN1C mutations: two sides of the same coin.
Trends Mol Med. 2014; 20(11):614-22 [PubMed] Related Publications
Cyclin-dependent kinase (CDK)-inhibitor 1C (CDKN1C) negatively regulates cellular proliferation and it has been shown that loss-of-function mutations in the imprinted CDKN1C gene (11p15.5) are associated with the overgrowth disorder Beckwith-Wiedemann syndrome (BWS). With recent reports of gain-of-function mutations of the PCNA domain of CDKN1C in growth-retarded patients with IMAGe syndrome or Silver-Russell syndrome (SRS), its key role for growth has been confirmed. Thereby, the last gap in the spectrum of molecular alterations in 11p15.5 in growth-retardation and overgrowth syndromes could be closed. Recent functional studies explain the strict association of CDKN1C mutations with clinically opposite phenotypes and thereby contribute to our understanding of the function and regulation of the gene in particular and epigenetic regulation in general.

Ohtsuka Y, Higashimoto K, Sasaki K, et al.
Autosomal recessive cystinuria caused by genome-wide paternal uniparental isodisomy in a patient with Beckwith-Wiedemann syndrome.
Clin Genet. 2015; 88(3):261-6 [PubMed] Related Publications
Approximately 20% of Beckwith-Wiedemann syndrome (BWS) cases are caused by mosaic paternal uniparental disomy of chromosome 11 (pUPD11). Although pUPD11 is usually limited to the short arm of chromosome 11, a small minority of BWS cases show genome-wide mosaic pUPD (GWpUPD). These patients show variable clinical features depending on mosaic ratio, imprinting status of other chromosomes, and paternally inherited recessive mutations. To date, there have been no reports of a mosaic GWpUPD patient with an autosomal recessive disease caused by a paternally inherited recessive mutation. Here, we describe a patient concurrently showing the clinical features of BWS and autosomal recessive cystinuria. Genetic analyses revealed that the patient has mosaic GWpUPD and an inherited paternal homozygous mutation in SLC7A9. This is the first report indicating that a paternally inherited recessive mutation can cause an autosomal recessive disease in cases of GWpUPD mosaicism. Investigation into recessive mutations and the dysregulation of imprinting domains is critical in understanding precise clinical conditions of patients with mosaic GWpUPD.

Mussa A, Pagliardini S, Pagliardini V, et al.
α-Fetoprotein assay on dried blood spot for hepatoblastoma screening in children with overgrowth-cancer predisposition syndromes.
Pediatr Res. 2014; 76(6):544-8 [PubMed] Related Publications
BACKGROUND: Beckwith-Wiedemann syndrome (BWS) and hemihyperplasia (HH) are overgrowth conditions with predisposition to hepatoblastoma for which early diagnosis patients undergo cancer screening based on determination of the tumor marker α-fetoprotein (αFP). Repeated blood draws are a burden for patients with consequent compliance issues and poor adherence to surveillance protocol. We sought to analyze feasibility and reliability of αFP dosage using an analytical micromethod based on blood dried on filter paper (DBS).
METHODS: Overall 143 coupled αFP determinations on plasma and DBS collected simultaneously were performed, of which 31 were in patients with hepatoblastoma predisposition syndromes and 112 were in controls. The plasma αFP dosage method was adapted to DBS adsorbed on paper matrix for newborn screening.
RESULTS: There was strong correlation between plasmatic and DBS αFP (r2 = 0.999, P < 0.001). Cohen's k coefficient for correlation was 0.96 for diagnostic cut-off of 10 U/ml (P < 0.001), commonly employed in clinical practice. The measurements on plasma and DBS were highly overlapping and consistent.
CONCLUSION: The DBS method allowed to dose αFP reliably and consistently for the concentrations commonly employed in clinical settings for the screening of hepatoblastoma, opening new scenarios about conducting cancer screening in overgrowth syndromes.

Kerns SL, Guevara-Aguirre J, Andrew S, et al.
A novel variant in CDKN1C is associated with intrauterine growth restriction, short stature, and early-adulthood-onset diabetes.
J Clin Endocrinol Metab. 2014; 99(10):E2117-22 [PubMed] Free Access to Full Article Related Publications
CONTEXT: CDKN1C, a cyclin-dependent kinase inhibitor and negative regulator of cellular proliferation, is paternally imprinted and has been shown to regulate β-cell proliferation. CDKN1C mutations are associated with growth disorders, including Beckwith-Wiedemann syndrome and IMAGe syndrome.
OBJECTIVE: To investigate the genetic basis for a familial disorder characterized by intrauterine growth restriction, short stature, and early-adulthood-onset diabetes.
DESIGN, SETTING, AND PARTICIPANTS: Genomic DNA samples (15 affected and 26 unaffected from a six-generation pedigree) were analyzed by genome-wide single nucleotide polymorphism arrays, whole exome and Sanger sequencing, and multiplex ligation-dependent probe amplification.
MAIN OUTCOME MEASURE(S): Subjects were assessed for height, weight, adrenal gland size, ACTH, diabetes status, and testis volume. Linkage and sequence analyses were performed, and the identified genetic variant was functionally evaluated in reconstitution studies.
RESULTS: The pedigree followed a paternally imprinted pattern of inheritance, and genetic linkage analysis identified a single significant 2.6-megabase locus on chromosome 11p15, within the imprinting center region 2. Multiplex ligation-dependent probe amplification did not detect copy number variants or methylation abnormalities. Whole exome sequencing revealed a single novel variant in the proliferating cell nuclear antigen-binding region of CDKN1C (c.842G>T, p.R281I) that co-segregated with affected status and, unlike variants found in IMAGe, did not entirely abrogate proliferating cell nuclear antigen binding. Clinical assessments revealed that affected individuals had low testicular volume but normal adrenal function.
CONCLUSIONS: We report a novel CDKN1C mutation associated with features of IMAGe syndrome, but without adrenal insufficiency or metaphyseal dysplasia, and characterized by early-adulthood-onset diabetes. Our data expand the range of phenotypes observed with CDKN1C defects and suggest that CDKN1C mutations may represent a novel monogenic form of diabetes.

Demars J, Shmela ME, Khan AW, et al.
Genetic variants within the second intron of the KCNQ1 gene affect CTCF binding and confer a risk of Beckwith-Wiedemann syndrome upon maternal transmission.
J Med Genet. 2014; 51(8):502-11 [PubMed] Related Publications
BACKGROUND: Disruption of 11p15 imprinting results in two fetal growth disorders with opposite phenotypes: the Beckwith-Wiedemann (BWS; MIM 130650) and the Silver-Russell (SRS; MIM 180860) syndromes. DNA methylation defects account for 60% of BWS and SRS cases and, in most cases, occur without any identified mutation in a cis-acting regulatory sequence or a trans-acting factor.
METHODS: We investigated whether 11p15 cis-acting sequence variants account for primary DNA methylation defects in patients with SRS and BWS with loss of DNA methylation at ICR1 and ICR2, respectively.
RESULTS: We identified a 4.5 kb haplotype that, upon maternal transmission, is associated with a risk of ICR2 loss of DNA methylation in patients with BWS. This novel region is located within the second intron of the KCNQ1 gene, 170 kb upstream of the ICR2 imprinting centre and encompasses two CTCF binding sites. We showed that, within the 4.5 kb region, two SNPs (rs11823023 and rs179436) affect CTCF occupancy at DNA motifs flanking the CTCF 20 bp core motif.
CONCLUSIONS: This study shows that genetic variants confer a risk of DNA methylation defect with a parent-of-origin effect and highlights the crucial role of CTCF for the regulation of genomic imprinting of the CDKN1C/KCNQ1 domain.

Weksberg R, Shuman C, Beckwith JB
Beckwith-Wiedemann syndrome.
Eur J Hum Genet. 2010; 18(1):8-14 [PubMed] Free Access to Full Article Related Publications
Beckwith-Wiedemann syndrome (BWS) is a model disorder for the study of imprinting, growth dysregulation, and tumorigenesis. Unique observations in this disorder point to an important embryonic developmental window relevant to the observations of increased monozygotic twinning and an increased rate of epigenetic errors after subfertility/assisted reproduction.

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