Molecular findings in Beckwith-Wiedemann syndrome

Identification of potential candidate genes for the Huoyan trait in developing Wulong goose embryos by transcriptomic analysis

1. The Wulong goose is a Chinese breed and a source of high-quality meat and eggs. A characteristic of the Wulong goose is that a proportion of the birds do not have eyelids, known as the Huoyon trait.2. Wulong geese exhibiting the Huoyan trait at embryonic stages of 9 days (E9), 12 days (E12) and 14 days (E14) were selected alongside those with normal eyelids for comprehensive transcriptome sequencing. Differentially expressed gene (DEG) and functional enrichment analyses were performed and finally, eight DEG were chosen to verify the accuracy of qPCR sequencing.3. Overall, 466, 962 and 550 DEG were obtained from the three control groups, D9 vs. N9, D12 vs. N12 and D14 vs. N14, respectively, by differential analysis (p < 0.05). CDKN1C, CRH, CROCC and TYSND1 were significantly expressed in the three groups. Enrichment analysis revealed the enrichment of CROCC and TYSND1 in pathways of cell cycle process, endocytosis, microtubule-based process, microtubule organising centre organisation, protein processing and protein maturation. CDKN1C and CRH were enriched in the cell cycle and cAMP signalling pathway.4. Some collagen family genes were detected among the DEGs, including COL3A1, COL4A5, COL4A2 and COL4A1. FREM1 and FREM2 genes were detected in both Huoyan and normal eyelids. There was a significant difference (p < 0.01) in FREM1 expression between ED9 and ED14 in female embryos, but this difference was not observed in male embryos.

Beckwith-Wiedemann syndrome with juvenile fibrous nodules and lobular breast tumors: a case report and review of the literature

BACKGROUND

Beckwith-Wiedemann syndrome (BWS) is a genomic imprinting disorder caused by diverse genetic and/or epigenetic disorders of chromosome 11p15.5. BWS presents with a variety of clinical features, including overgrowth and an increased risk of embryonal tumors. Notably however, reports of patients with BWS and breast tumors are rare, and the association between these conditions is still unclear. Insulin-like growth factor-2 (IGF2) expression is known to be associated with the development of various cancers, including breast cancer, and patients with BWS with specific subtypes of molecular defects are known to show characteristic clinical features and IGF2 overexpression.

CASE PRESENTATION

A 17-year-old girl who had been diagnosed with BWS based on an umbilical hernia, hyperinsulinemia, and left hemihypertrophy at birth, visited our department with a gradually swelling left breast. Her left breast was markedly larger than her right breast on visual examination. Imaging examinations showed two tumors measuring about 10 cm each in the left breast, and she was diagnosed with juvenile fibroadenoma following core needle biopsy. The two breast tumors were removed surgically and the patient remained alive with no recurrence. The final diagnosis was juvenile fibroadenoma without malignant findings. Immunohistochemical staining using IGF2 antibody revealed overexpression of IGF2 in the cytoplasm of ductal epithelial cells. Because of her clinical features and IGF2 overexpression, molecular defects of 11p15.5 including a possible genetic background of paternal uniparental disomy of chromosome 11 or hypermethylation of imprinting center 1 was suspected.

CONCLUSIONS

In this case, overexpression of IGF2 suggested a possible relationship between BWS and breast tumors. Moreover, the characteristic clinical features and IGF2 staining predicted the subtype of 11p15.5 molecular defects in this patient.

Beckwith-Wiedemann Syndrome in Newborn of Mother with HELLP Syndrome/Preeclampsia: An Analysis of Literature and Case Report with Fetal Growth Restriction and Absence of CDKN1C Typical Pathogenic Genetic Variation

Beckwith-Wiedemann Syndrome (BWS) is an imprinting disorder, which manifests by overgrowth and predisposition to embryonal tumors. The evidence on the relationship between maternal complications such as HELLP (hemolysis, elevated liver enzymes, and low platelet count) and preeclampsia and the development of BWS in offspring is scarce. A comprehensive clinical evaluation, with genetic testing focused on screening for mutations in the CDKN1C gene, which is commonly associated with BWS, was conducted in a newborn diagnosed with BWS born to a mother with a history of preeclampsia and HELLP syndrome. The case study revealed typical clinical manifestations of BWS in the newborn, including hemihyperplasia, macroglossia, midfacial hypoplasia, omphalocele, and hypoglycemia. Surprisingly, the infant also exhibited fetal growth restriction, a finding less commonly observed in BWS cases. Genetic analysis, however, showed no mutations in the CDKN1C gene, which contrasts with the majority of BWS cases. This case report highlights the complex nature of BWS and its potential association with maternal complications such as preeclampsia and HELLP syndrome. The atypical presence of fetal growth restriction in the newborn and the absence of CDKN1C gene mutations have not been reported to date in BWS.

Hereditary Conditions Associated with Elevated Cancer Risk in Childhood

Received January, 31, 2023 Revised March, 16, 2023 Accepted March, 18, 2023 Widespread use of the next-generation sequencing (NGS) technologies revealed that a significant percentage of tumors in children develop as a part of monogenic hereditary diseases. Predisposition to the development of pediatric neoplasms is characteristic of a wide range of conditions including hereditary tumor syndromes, primary immunodeficiencies, RASopathies, and phakomatoses. The mechanisms of tumor molecular pathogenesis are diverse and include disturbances in signaling cascades, defects in DNA repair, chromatin remodeling, and microRNA processing. Timely diagnosis of tumor-associated syndromes is important for the proper choice of cancer treatment, genetic counseling of families, and development of the surveillance programs. The review describes the spectrum of neoplasms characteristic of the most common syndromes and molecular pathogenesis of these diseases.

Wilms tumor: A case report with typical clinical and radiologic features in a 3-year-old male

Wilms' tumor, also known as nephroblastoma, is a rare cancer of the kidney that occurs almost exclusively in children. In this case report, a 3-year-old male presented to the hospital with left flank swelling and recurrent fever of 4 months duration. On examination, the abdomen was distended, with associated left flank fullness and distension of the anterior abdominal wall veins. A left nontender firm flank mass was palpated. Upon extensive imaging, the mass was revealed to be a nephroblastoma. The study reviews the use of imaging as a means of achieving a diagnosis and accurately measuring the size and magnitude of the tumor in order that treatment, whether surgery or chemotherapy, be commenced.

Co-Occurrence of Beckwith-Wiedemann Syndrome and Early-Onset Colorectal Cancer

CRC is an adult-onset carcinoma representing the third most common cancer and the second leading cause of cancer-related deaths in the world. EO-CRC (<45 years of age) accounts for 5% of the CRC cases and is associated with cancer-predisposing genetic factors in half of them. Here, we describe the case of a woman affected by BWSp who developed EO-CRC at age 27. To look for a possible molecular link between BWSp and EO-CRC, we analysed her whole-genome genetic and epigenetic profiles in blood, and peri-neoplastic and neoplastic colon tissues. The results revealed a general instability of the tumor genome, including copy number and methylation changes affecting genes of the WNT signaling pathway, CRC biomarkers and imprinted loci. At the germline level, two missense mutations predicted to be likely pathogenic were found in compound heterozygosity affecting the Cystic Fibrosis (CF) gene CFTR that has been recently classified as a tumor suppressor gene, whose dysregulation represents a severe risk factor for developing CRC. We also detected constitutional loss of methylation of the KCNQ1OT1:TSS-DMR that leads to bi-allelic expression of the lncRNA KCNQ1OT1 and BWSp. Our results support the hypothesis that the inherited CFTR mutations, together with constitutional loss of methylation of the KCNQ1OT1:TSS-DMR, initiate the tumorigenesis process. Further somatic genetic and epigenetic changes enhancing the activation of the WNT/beta-catenin pathway likely contributed to increase the growth advantage of cancer cells. Although this study does not provide any conclusive cause-effect relationship between BWSp and CRC, it is tempting to speculate that the imprinting defect of BWSp might accelerate tumorigenesis in adult cancer in the presence of predisposing genetic variants.

Implications of an Underlying Beckwith-Wiedemann Syndrome for Wilms Tumor Treatment Strategies

Beckwith-Wiedemann Syndrome (BWS) is a pediatric overgrowth disorder involving a predisposition to embryonal tumors. Most of the tumors associated with BWS occur in the first 8-10 years of life, and the most common is Wilms tumor (WT). BWS clinical heterogeneity includes subtle overgrowth features or even silent phenotypes, and WT may be the presenting symptom of BWS. WT in BWS individuals exhibit distinct characteristics from those of sporadic WT, and the management of these patients needs a peculiar approach. The most important feature is a higher risk of developing bilateral disease at some time in the course of the illness (synchronous bilateral disease at diagnosis or metachronous recurrence after initial presentation with unilateral disease). Accordingly, neoadjuvant chemotherapy is the recommended approach also for BWS patients with unilateral WT to facilitate nephron-sparing surgical approaches. This review emphasizes the importance of early BWS recognition, particularly if a WT has already occurred, as this will result in an urgent consideration of first-line cancer therapy.

Histopathologic Features of Adrenal Cortical Carcinoma

Adrenal cortical carcinoma (ACC) is a rare and aggressive malignancy that poses challenging issues regarding the diagnostic workup. Indeed, no presurgical technique or clinical parameters can reliably distinguish between adrenal cortical adenomas, which are more frequent and have a favorable outcome, and ACC, and the final diagnosis largely relies on histopathologic analysis of the surgical specimen. However, even the pathologic assessment of malignancy in an adrenal cortical lesion is not straightforward and requires a combined evaluation of multiple histopathologic features. Starting from the Weiss score, which was developed in 1984, several histopathologic scoring systems have been designed to tackle the difficulties of ACC diagnosis. Dealing with specific histopathologic variants (eg, Liss-Weiss-Bisceglia scoring system for oncocytic ACC) or patient characteristics (eg, Wieneke index in the pediatric setting), these scores remarkably improved the diagnostic workup of ACC and its subtypes. Nevertheless, cases with misleading features or discordant correlations between pathologic findings and clinical behavior still occur. Owing to multicentric collaborative studies integrating morphologic features with ancillary immunohistochemical markers and molecular analysis, ACC has eventually emerged as a multifaceted, heterogenous malignancy, and, while innovative and promising approaches are currently being tested, the future clinical management of patients with ACC will mainly rely on personalized medicine and target-therapy protocols. At the dawn of the new Fifth World Health Organization classification of endocrine tumors, this review will tackle ACC from the pathologist's perspective, thus focusing on the main available diagnostic, prognostic, and predictive tissue-tethered features and biomarkers and providing relevant clinical and molecular correlates.

Metastatic Phyllodes Tumor in a Patient With Beckwith-Wiedemann Syndrome

Beckwith-Wiedemann syndrome (BWS) is an epigenetic disorder of imprinting on the chromosome 11p15 region that presents with clinical features, such as macroglossia, abdominal wall defects, neonatal hypoglycemia, hemihypertrophy, and embryonal tumors. Phyllodes tumors (PTs) are rare fibroepithelial tumors that account for 0.3% to 1% of breast tumors and present in women aged 35 to 55 years. Here we describe a rare case of metastatic malignant phyllodes tumor in a 27-year-old woman with BWS and uniparental disomy (UPD) of chromosome 11p15.5. To our knowledge, this is the first case report in literature to describe metastatic malignant phyllodes tumor in a woman with BWS.

Hepatoblastoma in molecularly defined, congenital diseases

Beckwith-Wiedemann spectrum, Simpson-Golabi-Behmel syndrome, familial adenomatous polyposis and trisomy 18 are the most common congenital conditions associated with an increased incidence of hepatoblastoma (HB). In patients with these genetic disorders, screening protocols for HB are proposed that include periodic abdominal ultrasound and measurement of alpha-fetoprotein levels. Surveillance in these children may contribute to the early detection of HB and possibly improve their chances of overall survival. Therefore, physicians must be aware of the high HB incidence in children with certain predisposing genetic diseases.

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.

LncRNA-miRNA network analysis across the Th17 cell line reveals biomarker potency of lncRNA NEAT1 and KCNQ1OT1 in multiple sclerosis

Differentiation of CD⁴⁺ T cells into Th17 cells is an important factor in the onset and progression of multiple sclerosis (MS) and Th17/Treg imbalance. Little is known about the role of lncRNAs in the differentiation of CD⁴⁺ cells from Th17 cells. This study aimed to analyse the lncRNA‐miRNAs network involved in MS disease and its role in the differentiation of Th17 cells. The lncRNAs in Th17 differentiation were obtained from GSE66261 using the GEO datasets. Differential expression of lncRNAs in Th17 primary cells compared to Th17 effector cells was investigated by RNA‐seq analysis. Next, the most highlighted lncRNAs in autoimmune diseases were downloaded from the lncRNAs disease database, and the most critical miRNA was extracted by literature search. Then, the lncRNA‐miRNA interaction was achieved by the Starbase database, and the ceRNA network was designed by Cytoscape. Finally, using the CytoHubba application, two hub lncRNAs with the most interactions with miRNAs were identified by the MCODE plug‐in. The expression level of genes was measured by qPCR, and the plasma level of cytokines was analysed by ELISA kits. The results showed an increase in the expression of NEAT1, KCNQ1OT1 and RORC and a decrease in the expression of FOXP3. In plasma, an upregulation of IL17 and a downregulation of TGFB inflammatory cytokines were detected. The dysregulated expression of these genes could be attributed to relapsing‐remitting MS (RR‐MS) patients and help us understand MS pathogenesis better.

Loss of p57 Expression in Conceptions Other Than Complete Hydatidiform Mole: A Case Series With Emphasis on the Etiology, Genetics, and Clinical Significance

Combined p57 immunohistochemistry and DNA genotyping refines classification of products of conception specimens into specific types of hydatidiform moles and various nonmolar entities that can simulate them. p57 expression is highly correlated with genotyping and in practice can reliably be used to identify virtually all complete hydatidiform moles (CHM), but aberrant retained or lost p57 expression in rare CHMs and partial hydatidiform moles (PHM), as well as loss in some nonmolar abortuses, has been reported. Among a series of 2329 products of conceptions, we identified 10 cases for which loss of p57 expression was inconsistent with genotyping results (none purely androgenetic). They displayed a spectrum of generally mild abnormal villous morphology but lacked better developed features of CHMs/early CHMs, although some did suggest subtle forms of the latter. For 5 cases, genotyping (4 cases) and/or ancillary testing (1 case) determined a mechanism for the aberrant p57 results. These included 3 PHMs-2 diandric triploid and 1 triandric tetraploid-and 1 nonmolar specimen with loss of p57 expression attributable to partial or complete loss of the maternal copy of chromosome 11 and 1 nonmolar specimen with Beckwith-Wiedemann syndrome. For 5 cases, including 2 diandric triploid PHMs and 3 biparental nonmolar specimens, genotyping did not identify a mechanism, likely due to other genetic alterations which are below the resolution of or not targeted by genotyping. While overdiagnosis of a PHM as a CHM may cause less harm since appropriate follow-up with serum β-human chorionic gonadotropin levels would take place for both diagnoses, this could cause longer than necessary follow-up due to the expectation of a much greater risk of persistent gestational trophoblastic disease for CHM compared with PHM, which would be unfounded for the correct diagnosis of PHM. Overdiagnosis of a nonmolar abortus with loss of p57 expression as a CHM would lead to unnecessary follow-up and restriction on pregnancy attempts for patients with infertility. Genotyping is valuable for addressing discordance between p57 expression and morphology but cannot elucidate certain mechanisms of lost p57 expression. Future studies are warranted to determine whether chromosomal losses or gains, particularly involving imprinted genes such as p57, might play a role in modifying the risk of persistent gestational trophoblastic disease for PHMs and nonmolar conceptions that are not purely androgenetic but have some abnormal paternal imprinting of the type seen in CHMs.

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

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

Inherent mosaicism and extensive mutation of human placentas

Placentas can exhibit chromosomal aberrations that are absent from the fetus1. The basis of this genetic segregation, which is known as confined placental mosaicism, remains unknown. Here we investigated the phylogeny of human placental cells as reconstructed from somatic mutations, using whole-genome sequencing of 86 bulk placental samples (with a median weight of 28 mg) and of 106 microdissections of placental tissue. We found that every bulk placental sample represents a clonal expansion that is genetically distinct, and exhibits a genomic landscape akin to that of childhood cancer in terms of mutation burden and mutational imprints. To our knowledge, unlike any other healthy human tissue studied so far, the placental genomes often contained changes in copy number. We reconstructed phylogenetic relationships between tissues from the same pregnancy, which revealed that developmental bottlenecks genetically isolate placental tissues by separating trophectodermal lineages from lineages derived from the inner cell mass. Notably, there were some cases with full segregation-within a few cell divisions of the zygote-of placental lineages and lineages derived from the inner cell mass. Such early embryonic bottlenecks may enable the normalization of zygotic aneuploidy. We observed direct evidence for this in a case of mosaic trisomic rescue. Our findings reveal extensive mutagenesis in placental tissues and suggest that mosaicism is a typical feature of placental development.

Association of Assisted Reproductive Technology Treatments with Imprinting Disorders

Assisted reproductive technology (ART) is a broad field in infertility that encompasses different types of treatments. These revolutionary treatment methods aimed to aid infertile or subfertile couples. Treatment was expanded exponentially, as 1 to 3% of the births worldwide takes place with ART procedures. However, treatment is not flawless. Gametes and embryos are exposed to different chemicals and stress through treatment, which leads to disturbance in proper embryo development and results in prenatal and congenital anomalies. When compared with in-vivo development of gametes and preimplantation embryos in mice, in-vitro conditions during ART treatments have been suggested to disturb the gene expression levels, especially imprinted genes. Therefore, ART has been suggested to be associated with increased incidences of different imprinting disorders such as Beckwith–Wiedemann syndrome, Angelman syndrome, and Silver–Russell syndrome, as proved by different case reports and studies. This literature review aims to explain the association of imprinting disorders with this revolutionary treatment procedure.

Clinical Implications and Gender Differences of KCNQ1 p.Gly168Arg Pathogenic Variant in Long QT Syndrome

BACKGROUND

Long QT syndrome (LQTS) is an inheritable arrhythmogenic disorder associated with life-threatening arrhythmic events (LAEs). In general, patients with LQTS2 (KCNH2) and LQTS3 (SCN5A) are considered to be a greater risk of LAEs than LQTS1 (KCNQ1) patients. Gender differences are also important. Series analyzing families with the same pathogenic variants may help in the progress of elaborating strong specific genotype-phenotype management strategies. In this manuscript, we describe the phenotype of seven unrelated families, carriers of the KCNQ1 G168R pathogenic variant.

METHODS

we identified all consecutive index cases referred for genetic testing with LQTS diagnosis carriers of KCNQ1 G168R variant. Genetic and clinical screening for all available relatives was performed.

RESULTS

we evaluated seven unrelated families, with a total 34 KCNQ1 G168R carriers (two obligated carriers died without available EKGs to evaluate the phenotype). All index cases but one were women and three of them presented with aborted sudden cardiac death (SCD) or syncope. The presence of sudden death in these families is notable, with a total of nine unexplained sudden deaths and four aborted SCD. Phenotype penetrance was 100% in women and 37.5% in men.

CONCLUSIONS

KCNQ1 G168R is a pathogenic variant, with a high penetrance among women and mild penetrance among men. Risk for LAEs in this variant seems not negligible, especially among woman, and risk stratification should always be carefully evaluated.

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.

In-utero stress and mode of conception: impact on regulation of imprinted genes, fetal development and future health

BACKGROUND

Genomic imprinting is an epigenetic gene regulatory mechanism; disruption of this process during early embryonic development can have major consequences on both fetal and placental development. The periconceptional period and intrauterine life are crucial for determining long-term susceptibility to diseases. Treatments and procedures in assisted reproductive technologies (ART) and adverse in-utero environments may modify the methylation levels of genomic imprinting regions, including insulin-like growth factor 2 (IGF2)/H19, mesoderm-specific transcript (MEST), and paternally expressed gene 10 (PEG10), affecting the development of the fetus. ART, maternal psychological stress, and gestational exposures to chemicals are common stressors suspected to alter global epigenetic patterns including imprinted genes.

OBJECTIVE AND RATIONALE

Our objective is to highlight the effect of conception mode and maternal psychological stress on fetal development. Specifically, we monitor fetal programming, regulation of imprinted genes, fetal growth, and long-term disease risk, using the imprinted genes IGF2/H19, MEST, and PEG10 as examples. The possible role of environmental chemicals in genomic imprinting is also discussed.

SEARCH METHODS

A PubMed search of articles published mostly from 2005 to 2019 was conducted using search terms IGF2/H19, MEST, PEG10, imprinted genes, DNA methylation, gene expression, and imprinting disorders (IDs). Studies focusing on maternal prenatal stress, psychological well-being, environmental chemicals, ART, and placental/fetal development were evaluated and included in this review.

OUTCOMES

IGF2/H19, MEST, and PEG10 imprinted genes have a broad developmental effect on fetal growth and birth weight variation. Their disruption is linked to pregnancy complications, metabolic disorders, cognitive impairment, and cancer. Adverse early environment has a major impact on the developing fetus, affecting mostly growth, the structure, and subsequent function of the hypothalamic-pituitary-adrenal axis and neurodevelopment. Extensive evidence suggests that the gestational environment has an impact on epigenetic patterns including imprinting, which can lead to adverse long-term outcomes in the offspring. Environmental stressors such as maternal prenatal psychological stress have been found to associate with altered DNA methylation patterns in placenta and to affect fetal development. Studies conducted during the past decades have suggested that ART pregnancies are at a higher risk for a number of complications such as birth defects and IDs. ART procedures involve multiple steps that are conducted during critical windows for imprinting establishment and maintenance, necessitating long-term evaluation of children conceived through ART. Exposure to environmental chemicals can affect placental imprinting and fetal growth both in humans and in experimental animals. Therefore, their role in imprinting should be better elucidated, considering the ubiquitous exposure to these chemicals.

WIDER IMPLICATIONS

Dysregulation of imprinted genes is a plausible mechanism linking stressors such as maternal psychological stress, conception using ART, and chemical exposures with fetal growth. It is expected that a greater understanding of the role of imprinted genes and their regulation in fetal development will provide insights for clinical prevention and management of growth and IDs. In a broader context, evidence connecting impaired imprinted gene function to common diseases such as cancer is increasing. This implies early regulation of imprinting may enable control of long-term human health, reducing the burden of disease in the population in years to come.

Frequency of KCNQ1 variants causing loss of methylation of Imprinting Centre 2 in Beckwith-Wiedemann syndrome

Background

Beckwith-Wiedemann syndrome (BWS) is an imprinting disorder caused by disturbances of the chromosomal region 11p15.5. The most frequent molecular finding in BWS is loss of methylation (LOM) of the Imprinting Centre 2 (IC2) region on the maternal allele, which is localised in intron 10 of the KCNQ1 gene. In rare cases, LOM of IC2 has been reported in families with KCNQ1 germline variants which additionally cause long-QT syndrome (LQTS). Thus, a functional link between disrupted KCNQ1 transcripts and altered IC2 methylation has been suggested, resulting in the co-occurrence of LQTS and BWS in case of maternal inheritance. Whereas these cases were identified by chance or in patients with abnormal electrocardiograms, a systematic screen for KCNQ1 variants in IC2 LOM carriers has not yet been performed.

Results

We analysed 52 BWS patients with IC2 LOM to determine the frequency of germline variants in KCNQ1 by MLPA and an amplicon-based next generation sequencing approach. We identified one patient with a splice site variant causing premature transcription termination of KCNQ1.

Conclusions

Our study strengthens the hypothesis that proper KCNQ1 transcription is required for the establishment of IC2 methylation, but that KCNQ1 variants cause IC2 LOM only in a small number of BWS patients.

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

Background

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

Methods

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

Results

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

Conclusions

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

Deletion of BAF250a affects oocyte epigenetic modifications and embryonic development

BRG1-associated factor 250a (BAF250a) is a component of the SWI/SNF adenosine triphosphate-dependent chromatin remodeling complex, which has been shown to control chromatin structure and transcription. BAF250a was reported to be a key component of the gene regulatory machinery in embryonic stem cells controlling self-renewal, differentiation, and cell lineage decisions. Here we constructed Baf250a^F/F ;Gdf9-cre (Baf250a^CKO ) mice to specifically delete BAF250a in oocytes to investigate the role of maternal BAF250a in female germ cells and embryo development. Our results showed that BAF250a deletion did not affect folliculogenesis, ovulation, and fertilization, but it caused late embryonic death. RNA sequencing analysis showed that the expression of genes involved in cell proliferation and differentiation, tissue morphogenesis, histone modification, and nucleosome remodeling were perturbed in Baf250a^CKO MII oocytes. We showed that covalent histone modifications such as H3K27me3 and H3K27ac were also significantly affected in oocytes, which may reduce oocyte quality and lead to birth defects. In addition, the DNA methylation level of Igf2r, Snrpn, and Peg3 differentially methylated regions was decreased in Baf250a^CKO oocytes. Quantitative real-time polymerase chain reaction analysis showed that the relative messenger RNA (mRNA) expression levels of Igf2r and Snrpn were significantly increased. The mRNA expression level of Dnmt1, Dnmt3a, Dnmt3l, and Uhrf1 was decreased, and the protein expression in these genes was also reduced, which might be the cause for impaired imprinting establishment. In conclusion, our results demonstrate that BAF250a plays an important role in oocyte transcription regulation, epigenetic modifications, and embryo development.

In-depth characterization of the placental imprintome reveals novel differentially methylated regions across birth weight categories

Imprinted genes play a pivotal role in placental processes underlying fetal development, and much interest centers on discerning whether these loci, via changes in DNA methylation and/or gene expression, inform disruptions in appropriate fetal growth. In this study, we comprehensively profiled DNA methylation across the placental imprintome and assessed the relationship with gene expression levels and aberrant fetal growth.Placental DNA methylation across 153 imprinted loci, including imprint control regions (ICR) and surrounding non-ICR regions, was surveyed using the Nimblegen TruSeq bisulfite sequencing platform among participants enrolled in the Rhode Island Child Health Study (RICHS, n = 163). Methylation and gene expression associations were assessed using eQTM analysis. Differential methylation analysis contrasting small (SGA) and large for gestational age (LGA) infants against appropriate for gestational age (AGA) infants was assessed using the DMRcate R package.We identified 34 SGA-related differentially methylated regions (DMRs) and 9 LGA-related DMRs (FDR<0.05), and these BW-DMRs predominated in promoter and intronic regions. We observed overall hypomethylation among SGA-DMRs overlapping maternally expressed (paternally imprinted) genes while no parent-of-origin effect was observed among LGA DMRs. Three BW-DMRs, mapping to GABRG3, IGF1R and MEST, were common to SGA and LGA placenta. We did not observe significant correlations between BW-DMR-associated CpG methylation and gene expression levels.We report the first in-depth characterization of the placental imprintome in a population-wide setting. Our findings reveal growth-related differences in methylation without concomitant expression differences in regions that extend beyond typically interrogated imprinted loci, highlighting potentially novel placental biomarkers of growth and development.

Complex Phenotypes: Mechanisms Underlying Variation in Human Stature

PURPOSE OF REVIEW

The goal of the review is to provide a comprehensive overview of the current understanding of the mechanisms underlying variation in human stature.

RECENT FINDINGS

Human height is an anthropometric trait that varies considerably within human populations as well as across the globe. Historically, much research focus was placed on understanding the biology of growth plate chondrocytes and how modifications to core chondrocyte proliferation and differentiation pathways potentially shaped height attainment in normal as well as pathological contexts. Recently, much progress has been made to improve our understanding regarding the mechanisms underlying the normal and pathological range of height variation within as well as between human populations, and today, it is understood to reflect complex interactions among a myriad of genetic, environmental, and evolutionary factors. Indeed, recent improvements in genetics (e.g., GWAS) and breakthroughs in functional genomics (e.g., whole exome sequencing, DNA methylation analysis, ATAC-sequencing, and CRISPR) have shed light on previously unknown pathways/mechanisms governing pathological and common height variation. Additionally, the use of an evolutionary perspective has also revealed important mechanisms that have shaped height variation across the planet. This review provides an overview of the current knowledge of the biological mechanisms underlying height variation by highlighting new research findings on skeletal growth control with an emphasis on previously unknown pathways/mechanisms influencing pathological and common height variation. In this context, this review also discusses how evolutionary forces likely shaped the genomic architecture of height across the globe.

How Does Reprogramming to Pluripotency Affect Genomic Imprinting?

Human induced Pluripotent Stem Cells (hiPSCs) have the capacity to generate a wide range of somatic cells, thus representing an ideal tool for regenerative medicine. Patient-derived hiPSCs are also used for in vitro disease modeling and drug screenings. Several studies focused on the identification of DNA mutations generated, or selected, during the derivation of hiPSCs, some of which are known to drive cancer formation. Avoiding such stable genomic aberrations is paramount for successful use of hiPSCs, but it is equally important to ensure that their epigenetic information is correct, given the critical role of epigenetics in transcriptional regulation and its involvement in a plethora of pathologic conditions. In this review we will focus on genomic imprinting, a prototypical epigenetic mechanism whereby a gene is expressed in a parent-of-origin specific manner, thanks to the differential methylation of specific DNA sequences. Conventional hiPSCs are thought to be in a pluripotent state primed for differentiation. They display a hypermethylated genome with an unexpected loss of DNA methylation at imprinted loci. Several groups recently reported the generation of hiPSCs in a more primitive developmental stage, called naïve pluripotency. Naïve hiPSCs share several features with early human embryos, such as a global genome hypomethylation, which is also accompanied by a widespread loss of DNA methylation at imprinted loci. Given that loss of imprinting has been observed in genetic developmental disorders as well as in a wide range of cancers, it is fundamental to make sure that hiPSCs do not show such epigenetic aberrations. We will discuss what specific imprinted genes, associated with human pathologies, have been found commonly misregulated in hiPSCs and suggest strategies to effectively detect and avoid such undesirable epigenetic abnormalities.

Acute leukemia in a patient with 15q overgrowth syndrome

Overgrowth syndromes are rare genetic conditions which present as global or segmental hyperplasia and are sometimes associated with increased risk of malignancy. Trisomy of the terminal portion of 15q which includes the IGFR1 gene, produces a rare overgrowth phenotype that has been termed 15q overgrowth syndrome (15q OGS). Upregulation of IGF1R has long been implicated in oncogenesis of multiple cancer types, including acute leukemias, and has been shown to render cells more susceptible to other transforming events. To date, too few cases of 15q OGS have been reported to identify any cancer predisposition. We present a case of a 34-year-old female with intellectual disability, macrocephaly, and subtle dysmorphic features who was diagnosed with mixed phenotype acute leukemia (lymphoid and myeloid). Prior to initiation of therapy she was referred to medical genetics for further evaluation and was identified as having a chromosomal translocation resulting in a partial trisomy of chromosome 15q, consistent with 15q OGS. A review of the literature for cases of malignancy in individuals with increased copy number of 15q revealed only one other reported patient. Given the small number of reported individuals, we cannot rule out an increased risk of cancer associated with this chromosomal overgrowth syndrome. Although concerns have been raised regarding treatment feasibility in the setting of chromosomal disorders, the reported patient underwent successful treatment with allogeneic hematopoietic stem-cell transplant.

RNA-seq of Isolated Chromaffin Cells Highlights the Role of Sex-Linked and Imprinted Genes in Adrenal Medulla Development

Adrenal chromaffin cells and sympathetic neurons synthesize and release catecholamines, and both cell types are derived from neural crest precursors. However, they have different developmental histories, with sympathetic neurons derived directly from neural crest precursors while adrenal chromaffin cells arise from neural crest-derived cells that express Schwann cell markers. We have sought to identify the genes, including imprinted genes, which regulate the development of the two cell types in mice. We developed a method of separating the two cell types as early as E12.5, using differences in expression of enhanced yellow fluorescent protein driven from the tyrosine hydroxylase gene, and then used RNA sequencing to confirm the characteristic molecular signatures of the two cell types. We identified genes differentially expressed by adrenal chromaffin cells and sympathetic neurons. Deletion of a gene highly expressed by adrenal chromaffin cells, NIK-related kinase, a gene on the X-chromosome, results in reduced expression of adrenaline-synthesizing enzyme, phenyl-N-methyl transferase, by adrenal chromaffin cells and changes in cell cycle dynamics. Finally, many imprinted genes are up-regulated in chromaffin cells and may play key roles in their development.

The Role of AKT3 Copy Number Changes in Brain Abnormalities and Neurodevelopmental Disorders: Four New Cases and Literature Review

Microdeletions at 1q43-q44 have been described as resulting in a clinically recognizable phenotype of intellectual disability (ID), facial dysmorphisms and microcephaly (MIC). In contrast, the reciprocal microduplications of 1q43-q44 region have been less frequently reported and patients showed a variable phenotype, including macrocephaly. Reports of a large number of patients with copy number variations involving this region highlighted the AKT3 gene as a likely key player in head size anomalies. We report four novel patients with copy number variations in the 1q43-q44 region: one with a larger deletion (3.7Mb), two with smaller deletions affecting AKT3 and SDCCAG8 genes (0.16 and 0.18Mb) and one with a quadruplication (1Mb) that affects the entire AKT3 gene. All patients with deletions presented MIC without structural brain abnormalities, whereas the patient with quadruplication had macrocephaly, but his carrier father had normal head circumference. Our report also includes a comparison of phenotypes in cases with 1q43-q44 duplications to assist future genotype-phenotype correlations. Our observations implicate AKT3 as a contributor to ID/development delay (DD) and head size but raise doubts about its straightforward impact on the latter aspect of the phenotype in patients with 1q43-q44 deletion/duplication syndrome.

Disruption of KCNQ1 prevents methylation of the ICR2 and supports the hypothesis that its transcription is necessary for imprint establishment

Beckwith-Wiedemann syndrome (BWS; OMIM #130650) is an imprinting disorder caused by genetic or epigenetic alterations of one or both imprinting control regions on chromosome 11p15.5. Hypomethylation of the centromeric imprinting control region (KCNQ1OT1:TSS-DMR, ICR2) is the most common molecular cause of BWS and is present in about half of the cases. Based on a BWS family with a maternal deletion of the 5' part of KCNQ1 we have recently hypothesised that transcription of KCNQ1 is a prerequisite for the establishment of methylation at the KCNQ1OT1:TSS-DMR in the oocyte. Further evidence for this hypothesis came from a mouse model where methylation failed to be established when a poly(A) truncation cassette was inserted into this locus to prevent transcription through the DMR. Here we report on a family where a balanced translocation disrupts the KCNQ1 gene in intron 9. Maternal inheritance of this translocation is associated with hypomethylation of the KCNQ1OT1:TSS-DMR and BWS. This finding strongly supports our previous hypothesis that transcription of KCNQ1 is required for establishing the maternal methylation imprint at the KCNQ1OT1:TSS-DMR.

Tumor risk and surveillance for children with hereditary disorders affecting growth

PURPOSE OF REVIEW

Hereditary disorders affecting growth (both overgrowth and growth retardation) are frequently associated with heightened risk of neoplastic disease. This review summarizes the tumor spectra associated with these conditions and identifies disease-specific screening approaches.

RECENT FINDINGS

An understanding of the molecular events underlying many of these growth disorders has evolved significantly over the past several years. Recognition of genotype-phenotype associations, in many cases, informs the cancer risk profile. Additionally, accumulating data suggest a benefit of rational presymptomatic surveillance for at-risk individuals, with a reduction in tumor-associated morbidity. Recent clinical practice recommendations have established risk-driven paradigms for tumor surveillance in the context of hereditary tumor predisposition syndromes, including those affecting growth.

SUMMARY

Clinicians caring for children with growth disorders should be aware of syndromic associations and the associated cancer risks. Knowledge of tumor spectra and recommended surveillance strategies may facilitate tumor diagnosis at an early stage and reduce morbidity of the disease and associated treatments.

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.

Children's biobehavioral reactivity to challenge predicts DNA methylation in adolescence and emerging adulthood

A growing body of research has documented associations between adverse childhood environments and DNA methylation, highlighting epigenetic processes as potential mechanisms through which early external contexts influence health across the life course. The present study tested a complementary hypothesis: indicators of children's early internal, biological, and behavioral responses to stressful challenges may also be linked to stable patterns of DNA methylation later in life. Children's autonomic nervous system reactivity, temperament, and mental health symptoms were prospectively assessed from infancy through early childhood, and principal components analysis (PCA) was applied to derive composites of biological and behavioral reactivity. Buccal epithelial cells were collected from participants at 15 and 18 years of age. Findings revealed an association between early life biobehavioral inhibition/disinhibition and DNA methylation across many genes. Notably, reactive, inhibited children were found to have decreased DNA methylation of the DLX5 and IGF2 genes at both time points, as compared to non‐reactive, disinhibited children. Results of the present study are provisional but suggest that the gene's profile of DNA methylation may constitute a biomarker of normative or potentially pathological differences in reactivity. Overall, findings provide a foundation for future research to explore relations among epigenetic processes and differences in both individual‐level biobehavioral risk and qualities of the early, external childhood environment.

Macrocephaly: Solving the Diagnostic Dilemma

Macrocephaly is a relatively common clinical condition affecting up to 5% of the pediatric population. It is defined as an abnormally large head with an occipitofrontal circumference greater than 2 standard deviations above the mean for a given age and sex. Megalencephaly refers exclusively to brain overgrowth exceeding twice the standard deviation. Macrocephaly can be isolated and benign or may be the first indication of an underlying congenital, genetic, or acquired disorder, whereas megalencephaly is more often syndromic. Megalencephaly can be divided into 2 subtypes: metabolic and developmental, caused by genetic defects in cellular metabolism and alterations in signaling pathways, respectively. Neuroimaging plays an important role in the evaluation of macrocephaly, especially in the metabolic subtype which may not be overtly apparent clinically. This article outlines the diverse etiologies of macrocephaly, delineates their clinical and radiographic features, and suggests a clinicoradiological algorithm for evaluation.

Molecular pathogenesis of pancreatic ductal adenocarcinoma: Impact of passenger strand of pre-miR-148a on gene regulation

We previously used RNA sequencing to establish the microRNA (miRNA) expression signature of pancreatic ductal adenocarcinoma (PDAC). We found that both strands of pre-miR-148a (miR-148a-5p: the passenger strand and miR-148a-3p: the guide strand) were downregulated in cancer tissues. Ectopic expression of miR-148a-5p and miR-148a-3p significantly inhibited cancer cell migration and invasion, indicating that both strands of pre-miR-148a had tumor-suppressive roles in PDAC cells. In silico database and genome-wide gene expression analyses identified a total of 15 genes that were putative targets regulated by these miRNAs. High expression of miR-148a-5p targets (PHLDA2, LPCAT2 and AP1S3) and miR-148a-3p targets (SMA, ENDOD1 and UHMK1) was associated with poor prognosis of patients with PDAC. Moreover, knockdown of PHLDA2 expression inhibited cancer cell aggressiveness, suggesting PHLDA2 acted as an oncogene in PDAC cells. Involvement of the passenger strand of pre-miR-148a (miR-148-5p) is a new concept in cancer research. Novel approaches that identify tumor-suppressive miRNA regulatory networks in lethal PDAC might provide new prognostic markers and therapeutic targets for this disease.

Assisted Reproductive Technologies and imprinting disorders: Results of a study from a French congenital malformations registry

INTRODUCTION

Assisted Reproductive Technologies (ART) is increasingly used to help infertile couples to have children around the world. A number of studies have been published reporting an increased risk of major malformations in children born following ART, especially an increased incidence of epigenetic diseases (ED). This study aimed to assess the incidence of epigenetic diseases with affected imprinting genes in infants or children from pregnancies obtained through IVF/ICSI compared to infants or children from pregnancies obtained spontaneously.

PATIENT DATA

This is a monocentric retrospective epidemiological study based on data from a French congenital malformations registry called REMERA (Registre des Malformations en Rhône-Alpes) which exhaustively monitors all pregnancies in Rhone-Alpes region, whatever their nature of onset (spontaneous pregnancies or pregnancies from ART). This registry collects all malformations, except minor malformations (EUROCAT), and all polymalformative syndromes concerning all fetuses and children born alive or not, from 20 weeks of pregnancy (or 22 weeks of amenorrhea) and all medical termination of pregnancy whatever the term. Inclusion criteria are all diagnoses of epigenetic diseases (ED) related to parental imprinting recorded in the period January 2006 to December 2015.

METHODS

For each year, the total number of births (including stillbirths) was collected from the annual activity reports of the registry. The exhaustive number of cases of epigenetic diseases was known in the registry. Were collected the number of births resulting from ART pregnancies in the study population. This incidence of ED was compared between births from spontaneous pregnancies and those obtained through ART (IVF/ICSI) with a generalized linear model (GLM: binomial regression).

RESULTS

In total, 46 cases of epigenetic diseases were analyzed on the REMERA registry files from 2006 to 2015. 4 cases from the 46 analyzed cases were from pregnancies induced by ART. ART was a risk factor for epigenetic disease (OR = 2.9 [1.06-8.22] (p = .039)). In ART-pregnancies there were 2 diagnoses: Beckwith-Wiedemann syndrome (BWS) (3 cases out of 4) and Silver-Russell syndrome (SRS) (1 out of 4).

DISCUSSION

Infants and children obtained through IVF/ICSI appear to be related to a higher risk of epigenetic diseases compared to naturally conceived children. The perspectives of this study are to raise awareness about the creation of registries of congenital malformations and genetic and epigenetic syndromes with systematic and strict reports of all the cases on all the French territory and thus to widen this study with a bigger cohort.

Virginal breast hypertrophy in a patient with Beckwith-Wiedemann syndrome

Virginal breast hypertrophy is a multidisciplinary condition including surgical, pediatric, and endocrine/gynecological disciplines, and its successful diagnosis and management requires complex, team approach.

Seltene Tumordispositionssyndrome mit Manifestation im Kindesalter

Bei etwa 7–10 % der pädiatrischen Krebspatienten werden zugrunde liegende Tumordispositionssyndrome (TDS) vermutet. Das Erkennen von TDS hat klinische Implikationen für die Krebsprävention und -früherkennung, die Krebstherapie und -nachsorge, die psychosoziale Unterstützung sowie die Beratung von Angehörigen und Identifizierung weiterer Anlageträger in den betroffenen Familien. Hinweise auf das Vorliegen eines TDS anhand von Eigen- und Familienanamnese, Untersuchungsbefund sowie gegebenenfalls Tumorhistologie und -genetik müssen daher möglichst früh erkannt werden, um bei Verdacht auf Vorliegen eines TDS eine humangenetische Beratung und gegebenenfalls genetische Diagnostik zu veranlassen. Wissenschaftliche Untersuchungen zu TDS liefern Einblicke in die Biologie der Gewebe- und Tumorentwicklung und weisen auf mögliche Ansatzpunkte zielgerichteter Therapien hin. Die vorliegende Arbeit gibt eine Übersicht über TDS mit erhöhtem Risiko für Wilms-Tumoren (Nephroblastome), Neuroblastome oder Medulloblastome. Zusätzlich werden zwei vergleichsweise neu beschriebene Syndrome mit breitem Neoplasiespektrum erläutert: die konstitutionelle Mismatch-Reparatur-Defizienz (CMMRD) und das DICER1-Syndrom. Neben der Erläuterung der klinischen Charakteristika und der genetischen Grundlagen werden für die tägliche Praxis Hinweise zur Indikation von genetischen Untersuchungen und Früherkennung bei TDS aufgeführt. Die Betreuung der Betroffenen und ihrer Angehörigen sollte möglichst interdisziplinär erfolgen. Forschung zu TDS, zum Beispiel im Rahmen von Registern für TDS, ist essenziell, um langfristig die medizinische Versorgung von Menschen zu verbessern, die bedingt durch konstitutionelle genetische Veränderungen ein erhöhtes Krebsrisiko haben.

Wilms tumour in Beckwith-Wiedemann Syndrome and loss of methylation at imprinting centre 2: revisiting tumour surveillance guidelines

Beckwith-Wiedemann Syndrome (BWS) is an overgrowth syndrome caused by a variety of molecular changes on chromosome 11p15.5. Children with BWS have a significant risk of developing Wilms tumours with the degree of risk being dependent on the underlying molecular mechanism. In particular, only a relatively small number of children with loss of methylation at the centromeric imprinting centre (IC2) were reported to have developed Wilms tumour. Discontinuation of tumour surveillance for children with BWS and loss of methylation at IC2 has been proposed in several recent publications. We report here three children with BWS reported to have loss of methylation at IC2 on clinical testing who developed Wilms tumour or precursor lesions. Using multiple molecular approaches and multiple tissues, we reclassified one of these cases to paternal uniparental disomy for chromosome 11p15.5. These cases highlight the current challenges in definitively assigning tumour risk based on molecular classification in BWS. The confirmed cases of loss of methylation at IC2 also suggest that the risk of Wilms tumour in this population is not as low as previously thought. Therefore, we recommend that for now, all children with a clinical or molecular diagnosis of BWS be screened for Wilms tumour by abdominal ultrasonography until the age of eight years regardless of the molecular classification.

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.

Role of DNA methylation in imprinting disorders: an updated review

Genomic imprinting is a complex epigenetic process that contributes substantially to embryogenesis, reproduction, and gametogenesis. Only small fraction of genes within the whole genome undergoes imprinting. Imprinted genes are expressed in a monoallelic parent-of-origin-specific manner, which means that only one of the two inherited alleles is expressed either from the paternal or maternal side. Imprinted genes are typically arranged in clusters controlled by differentially methylated regions or imprinting control regions. Any defect or relaxation in imprinting process can cause loss of imprinting in the key imprinted loci. Loss of imprinting in most cases has a harmful effect on fetal development and can result in neurological, developmental, and metabolic disorders. Since DNA methylation and histone modifications play a key role in the process of imprinting. This review focuses on the role of DNA methylation in imprinting process and describes DNA methylation aberrations in different imprinting disorders.

Advanced paternal age effects in neurodevelopmental disorders-review of potential underlying mechanisms

Multiple epidemiological studies suggest a relationship between advanced paternal age (APA) at conception and adverse neurodevelopmental outcomes in offspring, particularly with regard to increased risk for autism and schizophrenia. Conclusive evidence about how age-related changes in paternal gametes, or age-independent behavioral traits affect neural development is still lacking. Recent evidence suggests that the origins of APA effects are likely to be multidimensional, involving both inherited predisposition and de novo events. Here we provide a review of the epidemiological and molecular findings to date. Focusing on the latter, we present the evidence for genetic and epigenetic mechanisms underpinning the association between late fatherhood and disorder in offspring. We also discuss the limitations of the APA literature. We propose that different hypotheses relating to the origins of the APA effects are not mutually exclusive. Instead, multiple mechanisms likely contribute, reflecting the etiological complexity of neurodevelopmental disorders.

An Update on Molecular Diagnostic Testing of Human Imprinting Disorders

Imprinted genes are expressed in a parent of origin manner. Dysregulation of imprinted genes expression causes various disorders associated with abnormalities of growth, neurodevelopment, and metabolism. Molecular mechanisms leading to imprinting disorders and strategies for their diagnosis are discussed in this review article.

Approach to the Diagnosis of Overgrowth Syndromes

Overgrowth syndromes comprise a group of disorders associated with excessive growth and other features such as facial dysmorphism, developmental delay or intellectual disability, congenital anomalies, neurological problems and an increased risk of neoplasia. Recent advances in understanding the genetic basis of overgrowth syndromes has resulted in a move away from clinical classification to molecular classification of overgrowth syndromes. This review provides a structured clinical approach to patients with this group of disorders and includes most of the currently known overgrowth syndromes.

Cancer Risk in Beckwith-Wiedemann Syndrome: A Systematic Review and Meta-Analysis Outlining a Novel (Epi)Genotype Specific Histotype Targeted Screening Protocol

OBJECTIVE

To compare tumor risk in the 4 Beckwith-Wiedemann syndrome (BWS) molecular subgroups: Imprinting Control Region 1 Gain of Methylation (ICR1-GoM), Imprinting Control Region 2 Loss of Methylation (ICR2-LoM), Chromosome 11p15 Paternal Uniparental Disomy (UPD), and Cyclin-Dependent Kinase Inhibitor 1C gene (CDKN1C) mutation.

STUDY DESIGN

Studies on BWS and tumor development published between 2000 and 2015 providing (epi)genotype-cancer correlations with histotype data were reviewed and meta-analysed with cancer histotypes as measured outcome and (epi)genotype as exposure.

RESULTS

A total of 1370 patients with BWS were included: 102 developed neoplasms (7.4%). Tumor prevalence was 2.5% in ICR2-LoM, 13.8% in UPD, 22.8% in ICR1-GoM, and 8.6% in patients with CDKN1C mutations. Cancer ORs were 12.8 in ICR1-GoM, 6.5 in UPD, and 2.9 in patients with CDKN1C mutations compared with patients with ICR2-LoM. Wilms tumor was associated with ICR1-GoM (OR 68.3) and UPD (OR 13.2). UPD also was associated with hepatoblastoma (OR 5.2) and adrenal carcinoma (OR 7.0), and CDKN1C mutations with neuroblastic tumors (OR 7.2).

CONCLUSION

Cancer screening in BWS could be differentiated on the basis of (epi)genotype and target specific histotypes. Patients with ICR1-GoM and UPD should undergo renal ultrasonography scanning, given their risk of Wilms tumor. Alpha feto protein monitoring for heptaoblastoma is suggested in patients with UPD. Adrenal carcinoma may deserve screening in patients with UPD. Patients with CDKN1C mutations may deserve neuroblastoma screening based on urinary markers and ultrasonography scanning. Finally, screening appears questionable in cases of ICR2-LoM, given low tumor risk.

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.

Phenotype, cancer risk, and surveillance in Beckwith-Wiedemann syndrome depending on molecular genetic subgroups

Patients with Beckwith-Wiedemann syndrome (BWS) have an increased risk to develop cancer in childhood, especially Wilms tumor and hepatoblastoma. The risk varies depending on the cause of BWS. We obtained clinical and molecular data in our cohort of children with BWS, including tumor occurrences, and correlated phenotype and genotype. We obtained similar data from larger cohorts reported in the literature. Phenotype, genotype and tumor occurrence were available in 229 of our own patients. Minor differences in phenotype existed depending on genotype/epigenotype, similar to earlier studies. By adding patients from the literature, we obtained data on genotype and tumor occurrence of in total 1,971 BWS patients. Tumor risks were highest in the IC1 (H19/IGF2:IG-DMR) hypermethylation subgroup (28%) and pUPD subgroup (16%) and were lower in the KCNQ1OT1:TSS-DMR (IC2) subgroup (2.6%), CDKN1C (6.9%) subgroup, and the group in whom no molecular defect was detectable (6.7%). Wilms tumors (median age 24 months) were frequent in the IC1 (24%) and pUPD (7.9%) subgroups. Hepatoblastoma occurred mostly in the pUPD (3.5%) and IC2 (0.7%) subgroups, never in the IC1 and CDKN1C subgroups, and always before 30 months of age. In the CDKN1C subgroup 2.8% of patients developed neuroblastoma. We conclude tumor risks in BWS differ markedly depending on molecular background. We propose a differentiated surveillance protocol, based on tumor risks in the various molecular subgroups causing BWS. © 2016 Wiley Periodicals, Inc.