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Ngo C, Baluyot M, Bennetts B, Carmichael J, Clark A, Darmanian A, Gayagay T, Jones L, Nash B, Clark M, Jose N, Robinson S, St Heaps L, Wright D. SNP chromosome microarray genotyping for detection of uniparental disomy in the clinical diagnostic laboratory. Pathology 2023; 55:818-826. [PMID: 37414616 DOI: 10.1016/j.pathol.2023.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 01/21/2023] [Accepted: 04/17/2023] [Indexed: 07/08/2023]
Abstract
Single nucleotide polymorphism (SNP) chromosome microarray is well established for investigation of children with intellectual deficit/development delay and prenatal diagnosis of fetal malformation but has also emerged for uniparental disomy (UPD) genotyping. Despite published guidelines on clinical indications for testing there are no laboratory guidelines published for performing SNP microarray UPD genotyping. We evaluated SNP microarray UPD genotyping using Illumina beadchips on family trios/duos within a clinical cohort (n=98) and then explored our findings in a post-study audit (n=123). UPD occurred in 18.6% and 19.5% cases, respectively, with chromosome 15 most frequent (62.5% and 25.0%). UPD was predominantly maternal in origin (87.5% and 79.2%), highest in suspected genomic imprinting disorder cases (56.3% and 41.7%) but absent amongst children of translocation carriers. We assessed regions of homozygosity among UPD cases. The smallest interstitial and terminal regions were 2.5 Mb and 9.3 Mb, respectively. We found regions of homozygosity confounded genotyping in a consanguineous case with UPD15 and another with segmental UPD due to non-informative probes. In a unique case with chromosome 15q UPD mosaicism, we established the detection limit of mosaicism as ∼5%. From the benefits and pitfalls identified in this study, we propose a testing model and recommendations for UPD genotyping by SNP microarray.
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Affiliation(s)
- Con Ngo
- Sydney Genome Diagnostics, Cytogenetics, The Children's Hospital at Westmead, Westmead, NSW, Australia.
| | - Maria Baluyot
- Sydney Genome Diagnostics, Cytogenetics, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - Bruce Bennetts
- Specialty of Genomic Medicine, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia; Sydney Genome Diagnostics, Molecular Genetics, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - Johanna Carmichael
- Sydney Genome Diagnostics, Cytogenetics, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - Alissa Clark
- Sydney Genome Diagnostics, Cytogenetics, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - Artur Darmanian
- Sydney Genome Diagnostics, Cytogenetics, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - Thet Gayagay
- Sydney Genome Diagnostics, Molecular Genetics, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - Luke Jones
- Sydney Genome Diagnostics, Cytogenetics, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - Benjamin Nash
- Sydney Genome Diagnostics, Cytogenetics, The Children's Hospital at Westmead, Westmead, NSW, Australia; Specialty of Genomic Medicine, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Melanie Clark
- Sydney Genome Diagnostics, Cytogenetics, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - Ngaire Jose
- Sydney Genome Diagnostics, Cytogenetics, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - Samantha Robinson
- Sydney Genome Diagnostics, Cytogenetics, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - Luke St Heaps
- Sydney Genome Diagnostics, Cytogenetics, The Children's Hospital at Westmead, Westmead, NSW, Australia; Specialty of Genomic Medicine, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Dale Wright
- Sydney Genome Diagnostics, Cytogenetics, The Children's Hospital at Westmead, Westmead, NSW, Australia; Specialty of Genomic Medicine, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
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Duffy KA, Getz KD, Hathaway ER, Byrne ME, MacFarland SP, Kalish JM. Characteristics Associated with Tumor Development in Individuals Diagnosed with Beckwith-Wiedemann Spectrum: Novel Tumor-(epi)Genotype-Phenotype Associations in the BWSp Population. Genes (Basel) 2021; 12:genes12111839. [PMID: 34828445 PMCID: PMC8621885 DOI: 10.3390/genes12111839] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/17/2021] [Accepted: 11/19/2021] [Indexed: 01/14/2023] Open
Abstract
Beckwith–Wiedemann Spectrum (BWSp) is the most common epigenetic childhood cancer predisposition disorder. BWSp is caused by (epi)genetic changes affecting the BWS critical region on chromosome 11p15. Clinically, BWSp represents complex molecular and phenotypic heterogeneity resulting in a range of presentations from Classic BWS to milder features. The previously reported tumor risk based on Classic BWS cohorts is 8–10% and routine tumor screening has been recommended. This work investigated the tumor risk and correlation with phenotype within a cohort of patients from Classic BWS to BWSp using a mixed-methods approach to explore phenotype and epigenotype profiles associated with tumor development through statistical analyses with post-hoc retrospective case series review. We demonstrated that tumor risk across BWSp differs from Classic BWS and that certain phenotypic features are associated with specific epigenetic causes; nephromegaly and/or hyperinsulinism appear associated with cancer in some patients. We also demonstrated that prenatal and perinatal factors that are not currently part of the BWSp classification may factor into tumor risk. Additionally, blood testing results are not necessarily synonymous with tissue testing results. Together, it appears that the current understanding from Classic BWS of (epi)genetics and phenotype correlations with tumors is not represented in the BWSp. Further study is needed in this complex population.
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Affiliation(s)
- Kelly A. Duffy
- Division of Human Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (K.A.D.); (E.R.H.); (M.E.B.)
| | - Kelly D. Getz
- Department of Biostatistics and Epidemiology, Perelman School of Medicine, Philadelphia, PA 19104, USA;
- Department of Pediatrics, Perelman School of Medicine, Philadelphia, PA 19104, USA;
| | - Evan R. Hathaway
- Division of Human Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (K.A.D.); (E.R.H.); (M.E.B.)
| | - Mallory E. Byrne
- Division of Human Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (K.A.D.); (E.R.H.); (M.E.B.)
| | - Suzanne P. MacFarland
- Department of Pediatrics, Perelman School of Medicine, Philadelphia, PA 19104, USA;
- Division of Oncology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Center for Childhood Cancer Research, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Jennifer M. Kalish
- Division of Human Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (K.A.D.); (E.R.H.); (M.E.B.)
- Department of Pediatrics, Perelman School of Medicine, Philadelphia, PA 19104, USA;
- Center for Childhood Cancer Research, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, Philadelphia, PA 19104, USA
- Correspondence: ; Tel.: +1-215-590-1278
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Quantitative DNA Methylation Analysis and Epigenotype-Phenotype Correlations in Taiwanese Patients with Beckwith-Wiedemann Syndrome. J Pers Med 2021; 11:jpm11111066. [PMID: 34834418 PMCID: PMC8622080 DOI: 10.3390/jpm11111066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/17/2021] [Accepted: 10/21/2021] [Indexed: 11/17/2022] Open
Abstract
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.
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Cancer incidence and spectrum among children with genetically confirmed Beckwith-Wiedemann spectrum in Germany: a retrospective cohort study. Br J Cancer 2020; 123:619-623. [PMID: 32451468 PMCID: PMC7434760 DOI: 10.1038/s41416-020-0911-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 04/22/2020] [Accepted: 05/06/2020] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Beckwith-Wiedemann syndrome (BWS) is a cancer predisposition syndrome caused by defects on chromosome 11p15.5. The quantitative cancer risks in BWS patients depend on the underlying (epi)genotype but have not yet been assessed in a population-based manner. METHODS We identified a group of 321 individuals with a molecularly confirmed diagnosis of BWS and analysed the cancer incidence up to age 15 years and cancer spectrum by matching their data with the German Childhood Cancer Registry. RESULTS We observed 13 cases of cancer in the entire BWS cohort vs 0.4 expected. This corresponds to a 33-fold increased risk (standardised incidence ratio (SIR) = 32.6; 95% confidence interval = 17.3-55.7). The specific cancers included hepatoblastoma (n = 6); nephroblastoma (n = 4); astrocytoma (n = 1); neuroblastoma (n = 1) and adrenocortical carcinoma (n = 1). The cancer SIR was highest in patients with a paternal uniparental disomy of 11p15.5 (UPDpat). A high cancer risk remained when cases of cancer diagnosed prior to the BWS diagnosis were excluded. CONCLUSIONS This study confirms an increased cancer risk in children with BWS. Our findings suggest that the highest cancer risk is associated with UPDpat. We were unable to confirm an excessive cancer risk in patients with IC1 gain of methylation (IC1-GOM) and this finding requires further investigation.
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Baker SW, Duffy KA, Richards-Yutz J, Deardorff MA, Kalish JM, Ganguly A. Improved molecular detection of mosaicism in Beckwith-Wiedemann Syndrome. J Med Genet 2020; 58:178-184. [PMID: 32430359 DOI: 10.1136/jmedgenet-2019-106498] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 03/19/2020] [Accepted: 04/02/2020] [Indexed: 12/17/2022]
Abstract
BACKGROUND Beckwith-Wiedemann Syndrome (BWS) is characterised by overgrowth and tumour predisposition. While multiple epigenetic and genetic mechanisms cause BWS, the majority are caused by methylation defects in imprinting control regions on chromosome 11p15.5. Disease-causing methylation defects are often mosaic within affected individuals. Phenotypic variability among individuals with chromosome 11p15.5 defects and tissue mosaicism led to the definition of the Beckwith-Wiedemann Spectrum (BWSp). Molecular diagnosis of BWSp requires use of multiple sensitive diagnostic techniques to reliably detect low-level aberrations. METHODS Multimodal BWS diagnostic testing was performed on samples from 1057 individuals. Testing included use of a sensitive qRT-PCR-based quantitation method enabling identification of low-level mosaic disease, identification of CNVs within 11p15.5 via array comparative genomic hybridisation or qRT-PCR, and Sanger sequencing of CDKN1C. RESULTS A molecular diagnosis was confirmed for 27.4% of individuals tested, of whom 43.4% had mosaic disease. The presence of a single cardinal feature was associated with a molecular diagnosis of BWSp in 20% of cases. Additionally, significant differences in the prevalence of mosaic disease among BWS molecular subtypes were identified. Finally, the diagnostic yield obtained by testing solid tissue samples from individuals with negative blood testing results shows improved molecular diagnosis. CONCLUSION This study highlights the prevalence of mosaic disease among individuals with BWSp and the increases in diagnostic yield obtained via testing both blood and solid tissue samples from affected individuals. Additionally, the results establish the presence of a molecular diagnosis in individuals with very subtle features of BWSp.
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Affiliation(s)
- Samuel W Baker
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Kelly A Duffy
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Jennifer Richards-Yutz
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Matthew A Deardorff
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Jennifer M Kalish
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA .,Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Arupa Ganguly
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
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Griff JR, Duffy KA, Kalish JM. Characterization and Childhood Tumor Risk Assessment of Genetic and Epigenetic Syndromes Associated With Lateralized Overgrowth. Front Pediatr 2020; 8:613260. [PMID: 33392121 PMCID: PMC7773942 DOI: 10.3389/fped.2020.613260] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 11/03/2020] [Indexed: 12/26/2022] Open
Abstract
Lateralized overgrowth (LO), or segmental overgrowth, is defined as an increase in growth of tissue (bone, muscle, connective tissue, vasculature, etc.) in any region of the body. Some overgrowth syndromes, characterized by both generalized and lateralized overgrowth, have been associated with an increased risk of tumor development. This may be due to the underlying genetic and epigenetic defects that lead to disrupted cell growth and proliferation pathways resulting in the overgrowth and tumor phenotypes. This chapter focuses on the four most common syndromes characterized by LO: Beckwith-Wiedemann spectrum (BWSp), PIK3CA-related overgrowth spectrum (PROS), Proteus syndrome (PS), and PTEN hamartoma tumor syndrome (PHTS). These syndromes demonstrate variable risks for tumor development in patients affected by LO, and we provide a comprehensive literature review of all common tumors reported in patients diagnosed with an LO-related disorder. This review summarizes the current data on tumor risk among these disorders and their associated tumor screening guidelines. Furthermore, this chapter highlights the importance of an accurate diagnosis when a patient presents with LO as similar phenotypes are associated with different tumor risks, thereby altering preventative screening protocols.
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Affiliation(s)
- Jessica R Griff
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Kelly A Duffy
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Jennifer M Kalish
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, United States.,Departments of Genetics and Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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Grafodatskaya D, Choufani S, Basran R, Weksberg R. An Update on Molecular Diagnostic Testing of Human Imprinting Disorders. J Pediatr Genet 2016; 6:3-17. [PMID: 28180023 DOI: 10.1055/s-0036-1593840] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 05/16/2016] [Indexed: 01/07/2023]
Abstract
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.
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Affiliation(s)
- Daria Grafodatskaya
- Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Sanaa Choufani
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Raveen Basran
- Pediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Rosanna Weksberg
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada; Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada; Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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White M, McGillivray G, White SM, Zacharin MR. First report of congenital adrenal cysts and pheochromocytoma in a patient with mosaic genome-wide paternal uniparental disomy. Am J Med Genet A 2016; 170:3352-3355. [DOI: 10.1002/ajmg.a.37959] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 08/04/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Mary White
- The Department of Endocrinology and Diabetes; The Royal Children's Hospital; Melbourne Australia
| | - George McGillivray
- Victorian Clinical Genetics Services; Murdoch Childrens Research Institute; Melbourne Australia
| | - Sue M. White
- Victorian Clinical Genetics Services; Murdoch Childrens Research Institute; Melbourne Australia
- Department of Paediatrics; University of Melbourne; Melbourne Australia
| | - Margaret R. Zacharin
- The Department of Endocrinology and Diabetes; The Royal Children's Hospital; Melbourne Australia
- Department of Paediatrics; University of Melbourne; Melbourne Australia
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Lin HY, Chuang CK, Tu RY, Fang YY, Su YN, Chen CP, Chang CY, Liu HC, Chu TH, Niu DM, Lin SP. Epigenotype, genotype, and phenotype analysis of patients in Taiwan with Beckwith-Wiedemann syndrome. Mol Genet Metab 2016; 119:8-13. [PMID: 27436784 DOI: 10.1016/j.ymgme.2016.07.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Revised: 07/10/2016] [Accepted: 07/10/2016] [Indexed: 01/02/2023]
Abstract
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.
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Affiliation(s)
- Hsiang-Yu Lin
- Department of Medicine, Mackay Medical College, New Taipei City, Taiwan; Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan; Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan; Mackay Junior College of Medicine, Nursing and Management, Taipei, Taiwan; Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Chih-Kuang Chuang
- Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan; Medical College, Fu-Jen Catholic University, Taipei, Taiwan; Institute of Biotechnology, National Taipei University of Technology, Taipei, Taiwan
| | - Ru-Yi Tu
- Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan
| | - Yi-Ya Fang
- Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan
| | - Yi-Ning Su
- Department of Obstetrics and Gynecology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chih-Ping Chen
- Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan; Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan
| | - Chia-Ying Chang
- Department of Pediatrics, Mackay Memorial Hospital, Hsinchu, Taiwan
| | - Hsi-Che Liu
- Department of Medicine, Mackay Medical College, New Taipei City, Taiwan; Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan
| | - Tzu-Hung Chu
- Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Dau-Ming Niu
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Shuan-Pei Lin
- Department of Medicine, Mackay Medical College, New Taipei City, Taiwan; Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan; Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan; Department of Infant and Child Care, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan.
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Russo S, Calzari L, Mussa A, Mainini E, Cassina M, Di Candia S, Clementi M, Guzzetti S, Tabano S, Miozzo M, Sirchia S, Finelli P, Prontera P, Maitz S, Sorge G, Calcagno A, Maghnie M, Divizia MT, Melis D, Manfredini E, Ferrero GB, Pecile V, Larizza L. 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. [PMID: 26933465 PMCID: PMC4772365 DOI: 10.1186/s13148-016-0183-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 02/08/2016] [Indexed: 12/20/2022] Open
Abstract
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.
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Affiliation(s)
- Silvia Russo
- Human Molecular Genetics Laboratory, IRCCS Istituto Auxologico Italiano, Milano, Italy
| | - Luciano Calzari
- Human Molecular Genetics Laboratory, IRCCS Istituto Auxologico Italiano, Milano, Italy
| | - Alessandro Mussa
- Department of Pediatric and Public Health Sciences, University of Turin, Torino, Italy
| | - Ester Mainini
- Human Molecular Genetics Laboratory, IRCCS Istituto Auxologico Italiano, Milano, Italy
| | - Matteo Cassina
- Clinical Genetics Unit, Department of Women's and Children's Health, University of Padua, Padova, Italy
| | - Stefania Di Candia
- Department of Pediatrics, San Raffaele Scientific Institute, Milano, Italy
| | - Maurizio Clementi
- Clinical Genetics Unit, Department of Women's and Children's Health, University of Padua, Padova, Italy
| | - Sara Guzzetti
- Human Molecular Genetics Laboratory, IRCCS Istituto Auxologico Italiano, Milano, Italy
| | - Silvia Tabano
- Division of Pathology - Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Department of Pathophysiology and Transplantation, University of Milan, Milano, Italy
| | - Monica Miozzo
- Division of Pathology - Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Department of Pathophysiology and Transplantation, University of Milan, Milano, Italy
| | - Silvia Sirchia
- Department of Health Sciences, University of Milan, Milano, Italy
| | - Palma Finelli
- Human Molecular Genetics Laboratory, IRCCS Istituto Auxologico Italiano, Milano, Italy
| | - Paolo Prontera
- Medical Genetics Unit, Department of Surgical and Biomedical Sciences, University of Perugia, Hospital "S. M. della Misericordia", Perugia, Italy
| | - Silvia Maitz
- Clinical Pediatric Genetics Unit, Pediatrics Clinics, MBBM Foundation, S. Gerardo Hospital, Monza, Italy
| | - Giovanni Sorge
- Department of Pediatrics and Medical Sciences, AO "Policlinico Vittorio Emanuele", Catania, Italy
| | - Annalisa Calcagno
- Pediatric Endocrine Unit, Department of Pediatrics, IRCCS, Children's Hospital Giannina Gaslini, Genova, Italy
| | - Mohamad Maghnie
- Pediatric Endocrine Unit, Department of Pediatrics, IRCCS, Children's Hospital Giannina Gaslini, Genova, Italy
| | - Maria Teresa Divizia
- Department of Medical Genetics, IRCCS, Children's Hospital Giannina Gaslini, Genova, Italy
| | - Daniela Melis
- Clinical Pediatric Genetics, Department of Pediatrics, University "Federico II", Napoli, Italy
| | - Emanuela Manfredini
- Medical Genetics Unit, Department of Laboratory Medicine, Niguarda Ca' Granda Hospital, Milano, Italy
| | | | - Vanna Pecile
- Institute for Maternal and Child Health, Foundation IRCCS Burlo Garofolo Institute, Trieste, Italy
| | - Lidia Larizza
- Human Molecular Genetics Laboratory, IRCCS Istituto Auxologico Italiano, Milano, Italy
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Kalish JM, Boodhansingh KE, Bhatti TR, Ganguly A, Conlin LK, Becker SA, Givler S, Mighion L, Palladino AA, Adzick NS, De León DD, Stanley CA, Deardorff MA. Congenital hyperinsulinism in children with paternal 11p uniparental isodisomy and Beckwith-Wiedemann syndrome. J Med Genet 2016; 53:53-61. [PMID: 26545876 PMCID: PMC4740975 DOI: 10.1136/jmedgenet-2015-103394] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 10/16/2015] [Indexed: 01/03/2023]
Abstract
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.
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Affiliation(s)
- Jennifer M Kalish
- Division of Human Genetics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pediatrics, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kara E Boodhansingh
- Division of Endocrinology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Tricia R Bhatti
- Department of Pathology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pathology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Arupa Ganguly
- Department of Genetics, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Laura K Conlin
- Department of Pathology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pathology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Susan A Becker
- Division of Endocrinology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Stephanie Givler
- Division of Endocrinology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Lindsey Mighion
- Department of Genetics, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Andrew A Palladino
- Department of Pediatrics, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Division of Endocrinology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - N Scott Adzick
- Department of Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Surgery, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Diva D De León
- Department of Pediatrics, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Division of Endocrinology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Charles A Stanley
- Department of Pediatrics, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Division of Endocrinology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Matthew A Deardorff
- Division of Human Genetics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pediatrics, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
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12
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Opitz award winners focus on hemihyperplasia, Kabuki syndrome. Am J Med Genet A 2014; 164A:viii-ix. [DOI: 10.1002/ajmg.a.36756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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13
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Ibrahim A, Kirby G, Hardy C, Dias RP, Tee L, Lim D, Berg J, MacDonald F, Nightingale P, Maher ER. Methylation analysis and diagnostics of Beckwith-Wiedemann syndrome in 1,000 subjects. Clin Epigenetics 2014; 6:11. [PMID: 24982696 PMCID: PMC4064264 DOI: 10.1186/1868-7083-6-11] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 05/09/2014] [Indexed: 11/30/2022] Open
Abstract
Background Beckwith-Wiedemann syndrome (BWS), a congenital overgrowth disorder with variable expressivity and a predisposition to tumorigenesis, results from disordered expression and/or function of imprinted genes at chromosome 11p15.5. There are no generally agreed clinical diagnostic criteria, with molecular studies commonly performed to confirm diagnosis. In particular, methylation status analysis at two 11p15.5 imprinting control centres (IC1 and IC2) detects up to 80% of BWS cases (though low-level mosaicism may not be detected). In order to evaluate the relationship between the clinical presentation of suspected BWS and IC1/2 methylation abnormalities we reviewed the results of >1,000 referrals for molecular diagnostic testing. Results Out of 1,091 referrals, 507 (46.5%) had a positive diagnostic test for BWS. The frequency of tumours was 3.4% in those with a molecular diagnosis of BWS. Previously reported genotype-phenotype associations with paternal uniparental disomy, IC1, and IC2 epimutation groups were confirmed and potential novel associations detected. Predictive values of previously described clinical diagnostic criteria were compared and, although there were differences in their sensitivity and specificity, receiver operating characteristic (ROC) analysis demonstrated that these were not optimal in predicting 11p15.5 methylation abnormalities. Using logistic regression, we identified clinical features with the best predictive value for a positive methylation abnormality. Furthermore, we developed a weighted scoring system (sensitivity 75.9%, and specificity 81.8%) to prioritise patients presenting with the most common features of BWS, and ROC analysis demonstrated superior performance (area under the curve 0.85, 95% CI 0.83 to 0.87) compared to previous criteria. Conclusions We suggest that this novel tool will facilitate selection of patients with suspected BWS for routine diagnostic testing and so improve the diagnosis of the disorder.
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Affiliation(s)
- Abdulla Ibrahim
- Department of Medical Genetics, University of Cambridge and NIHR Cambridge Biomedical Research Centre, Cambridge CB2 0QQ, UK ; Department of Clinical Genetics, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
| | - Gail Kirby
- Centre for Rare Diseases and Personalised Medicine, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Carol Hardy
- West Midlands Regional Genetics Service, Birmingham Women's Hospital, Birmingham B15 2TG, UK
| | - Renuka P Dias
- Centre for Rare Diseases and Personalised Medicine, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Louise Tee
- Centre for Rare Diseases and Personalised Medicine, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Derek Lim
- Centre for Rare Diseases and Personalised Medicine, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK ; West Midlands Regional Genetics Service, Birmingham Women's Hospital, Birmingham B15 2TG, UK
| | - Jonathan Berg
- Department of Clinical Genetics, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
| | - Fiona MacDonald
- West Midlands Regional Genetics Service, Birmingham Women's Hospital, Birmingham B15 2TG, UK
| | - Peter Nightingale
- Wellcome Trust Clinical Research Facility, University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital, Birmingham B15 2TH, UK
| | - Eamonn R Maher
- Department of Medical Genetics, University of Cambridge and NIHR Cambridge Biomedical Research Centre, Cambridge CB2 0QQ, UK ; Centre for Rare Diseases and Personalised Medicine, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
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14
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Calvello M, Tabano S, Colapietro P, Maitz S, Pansa A, Augello C, Lalatta F, Gentilin B, Spreafico F, Calzari L, Perotti D, Larizza L, Russo S, Selicorni A, Sirchia SM, Miozzo M. Quantitative DNA methylation analysis improves epigenotype-phenotype correlations in Beckwith-Wiedemann syndrome. Epigenetics 2013; 8:1053-60. [PMID: 23917791 PMCID: PMC3891686 DOI: 10.4161/epi.25812] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Beckwith-Wiedemann syndrome (BWS) is a rare disorder characterized by overgrowth and predisposition to embryonal tumors. BWS is caused by various epigenetic and/or genetic alterations that dysregulate the imprinted genes on chromosome region 11p15.5. Molecular analysis is required to reinforce the clinical diagnosis of BWS and to identify BWS patients with cancer susceptibility. This is particularly crucial prenatally because most signs of BWS cannot be recognized in utero. We established a reliable molecular assay by pyrosequencing to quantitatively evaluate the methylation profiles of ICR1 and ICR2. We explored epigenotype-phenotype correlations in 19 patients that fulfilled the clinical diagnostic criteria for BWS, 22 patients with suspected BWS, and three fetuses with omphalocele. Abnormal methylation was observed in one prenatal case and 19 postnatal cases, including seven suspected BWS. Seven cases showed ICR1 hypermethylation, five cases showed ICR2 hypomethylation, and eight cases showed abnormal methylation of ICR1 and ICR2 indicating paternal uniparental disomy (UPD). More cases of ICR1 alterations and UPD were found than expected. This is likely due to the sensitivity of this approach, which can detect slight deviations in methylation from normal levels. There was a significant correlation (p < 0.001) between the percentage of ICR1 methylation and BWS features: severe hypermethylation (range: 75–86%) was associated with macroglossia, macrosomia, and visceromegaly, whereas mild hypermethylation (range: 55–59%) was associated with umbilical hernia and diastasis recti. Evaluation of ICR1 and ICR2 methylation by pyrosequencing in BWS can improve epigenotype-phenotype correlations, detection of methylation alterations in suspected cases, and identification of UPD.
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Affiliation(s)
- Mariarosaria Calvello
- Division of Pathology; Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico; Milano, Italy
| | - Silvia Tabano
- Division of Pathology; Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico; Milano, Italy; Department of Pathophysiology and Transplantation; Università degli Studi di Milano; Milano, Italy
| | - Patrizia Colapietro
- Department of Health Sciences; Università degli Studi di Milano; Milano, Italy
| | - Silvia Maitz
- Clinical Genetics; Pediatric Department; S. Gerardo Hospital; Fondazione MBBM; Università di Milano-Bicocca; Monza, Italy
| | - Alessandra Pansa
- Department of Pathophysiology and Transplantation; Università degli Studi di Milano; Milano, Italy
| | - Claudia Augello
- Department of Pathophysiology and Transplantation; Università degli Studi di Milano; Milano, Italy
| | - Faustina Lalatta
- Clinical Genetics Unit; Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico; Milano, Italy
| | - Barbara Gentilin
- Clinical Genetics Unit; Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico; Milano, Italy
| | - Filippo Spreafico
- Pediatric Oncology Unit; Fondazione IRCCS Istituto Nazionale dei Tumori; Milano, Italy
| | - Luciano Calzari
- Molecular Biology Laboratory; Istituto Auxologico Italiano; Milano, Italy
| | - Daniela Perotti
- Molecular Bases of Genetic Risk and Genetic Testing Unit; Department of Preventive and Predictive Medicine; Fondazione IRCCS Istituto Nazionale dei Tumori; Milano, Italy
| | - Lidia Larizza
- Department of Health Sciences; Università degli Studi di Milano; Milano, Italy; Molecular Biology Laboratory; Istituto Auxologico Italiano; Milano, Italy
| | - Silvia Russo
- Molecular Biology Laboratory; Istituto Auxologico Italiano; Milano, Italy
| | - Angelo Selicorni
- Clinical Genetics; Pediatric Department; S. Gerardo Hospital; Fondazione MBBM; Università di Milano-Bicocca; Monza, Italy
| | - Silvia M Sirchia
- Division of Pathology; Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico; Milano, Italy; Department of Health Sciences; Università degli Studi di Milano; Milano, Italy
| | - Monica Miozzo
- Division of Pathology; Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico; Milano, Italy; Department of Pathophysiology and Transplantation; Università degli Studi di Milano; Milano, Italy
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15
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Kalish JM, Conlin LK, Bhatti TR, Dubbs HA, Harris MC, Izumi K, Mostoufi-Moab S, Mulchandani S, Saitta S, States LJ, Swarr DT, Wilkens AB, Zackai EH, Zelley K, Bartolomei MS, Nichols KE, Palladino AA, Spinner NB, Deardorff MA. Clinical features of three girls with mosaic genome-wide paternal uniparental isodisomy. Am J Med Genet A 2013; 161A:1929-39. [PMID: 23804593 DOI: 10.1002/ajmg.a.36045] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 04/19/2013] [Indexed: 12/14/2022]
Abstract
Here we describe three subjects with mosaic genome-wide paternal uniparental isodisomy (GWpUPD) each of whom presented initially with overgrowth, hemihyperplasia (HH), and hyperinsulinism (HI). Due to the severity of findings and the presence of additional features, SNP array testing was performed, which demonstrated mosaic GWpUPD. Comparing these individuals to 10 other live-born subjects reported in the literature, the predominant phenotype is that of pUPD11 and notable for a very high incidence of tumor development. Our subjects developed non-metastatic tumors of the adrenal gland, kidney, and/or liver. All three subjects had pancreatic hyperplasia resulting in HI. Notably, our subjects to date display minimal features of other diseases associated with paternal UPD loci. Both children who survived the neonatal period have displayed near-normal cognitive development, likely due to a favorable tissue distribution of the mosaicism. To understand the range of UPD mosaicism levels, we studied multiple tissues using SNP array analysis and detected levels of 5-95%, roughly correlating with the extent of tissue involvement. Given the rapidity of tumor growth and the difficulty distinguishing malignant and benign tumors in these GWpUPD subjects, we have utilized increased frequency of ultrasound (US) and alpha-fetoprotein (AFP) screening in the first years of life. Because of a later age of onset of additional tumors, continued tumor surveillance into adolescence may need to be considered in these rare patients.
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Affiliation(s)
- Jennifer M Kalish
- The Division of Genetics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
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