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Castilla-Vallmanya L, Centeno-Pla M, Serrano M, Franco-Valls H, Martínez-Cabrera R, Prat-Planas A, Rojano E, Ranea JAG, Seoane P, Oliva C, Paredes-Fuentes AJ, Marfany G, Artuch R, Grinberg D, Rabionet R, Balcells S, Urreizti R. Advancing in Schaaf-Yang syndrome pathophysiology: from bedside to subcellular analyses of truncated MAGEL2. J Med Genet 2023; 60:406-415. [PMID: 36243518 PMCID: PMC10086475 DOI: 10.1136/jmg-2022-108690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 07/27/2022] [Indexed: 11/04/2022]
Abstract
BACKGROUND Schaaf-Yang syndrome (SYS) is caused by truncating mutations in MAGEL2, mapping to the Prader-Willi region (15q11-q13), with an observed phenotype partially overlapping that of Prader-Willi syndrome. MAGEL2 plays a role in retrograde transport and protein recycling regulation. Our aim is to contribute to the characterisation of SYS pathophysiology at clinical, genetic and molecular levels. METHODS We performed an extensive phenotypic and mutational revision of previously reported patients with SYS. We analysed the secretion levels of amyloid-β 1-40 peptide (Aβ1-40) and performed targeted metabolomic and transcriptomic profiles in fibroblasts of patients with SYS (n=7) compared with controls (n=11). We also transfected cell lines with vectors encoding wild-type (WT) or mutated MAGEL2 to assess stability and subcellular localisation of the truncated protein. RESULTS Functional studies show significantly decreased levels of secreted Aβ1-40 and intracellular glutamine in SYS fibroblasts compared with WT. We also identified 132 differentially expressed genes, including non-coding RNAs (ncRNAs) such as HOTAIR, and many of them related to developmental processes and mitotic mechanisms. The truncated form of MAGEL2 displayed a stability similar to the WT but it was significantly switched to the nucleus, compared with a mainly cytoplasmic distribution of the WT MAGEL2. Based on the updated knowledge, we offer guidelines for the clinical management of patients with SYS. CONCLUSION A truncated MAGEL2 protein is stable and localises mainly in the nucleus, where it might exert a pathogenic neomorphic effect. Aβ1-40 secretion levels and HOTAIR mRNA levels might be promising biomarkers for SYS. Our findings may improve SYS understanding and clinical management.
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Affiliation(s)
- Laura Castilla-Vallmanya
- Department of Genetics, Microbiology and Statistics, IBUB, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Institut de Recerca Sant Joan de Déu, Espluques de Llobregat, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instiuto de Salud Carlos III, Madrid, Spain
| | - Mónica Centeno-Pla
- Department of Genetics, Microbiology and Statistics, IBUB, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Institut de Recerca Sant Joan de Déu, Espluques de Llobregat, Barcelona, Spain
- Clinical Biochemistry Department, Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain
| | - Mercedes Serrano
- Institut de Recerca Sant Joan de Déu, Espluques de Llobregat, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instiuto de Salud Carlos III, Madrid, Spain
- Neurology Department, Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain
| | - Héctor Franco-Valls
- Department of Genetics, Microbiology and Statistics, IBUB, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Raúl Martínez-Cabrera
- Department of Genetics, Microbiology and Statistics, IBUB, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Aina Prat-Planas
- Department of Genetics, Microbiology and Statistics, IBUB, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Institut de Recerca Sant Joan de Déu, Espluques de Llobregat, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instiuto de Salud Carlos III, Madrid, Spain
| | - Elena Rojano
- Department of Molecular Biology and Biochemistry; Institute of Biomedical Research in Málaga (IBIMA), University of Málaga, Málaga, Spain
| | - Juan A G Ranea
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instiuto de Salud Carlos III, Madrid, Spain
- Department of Molecular Biology and Biochemistry; Institute of Biomedical Research in Málaga (IBIMA), University of Málaga, Málaga, Spain
| | - Pedro Seoane
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instiuto de Salud Carlos III, Madrid, Spain
- Department of Molecular Biology and Biochemistry; Institute of Biomedical Research in Málaga (IBIMA), University of Málaga, Málaga, Spain
| | - Clara Oliva
- Institut de Recerca Sant Joan de Déu, Espluques de Llobregat, Barcelona, Spain
- Clinical Biochemistry Department, Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain
| | - Abraham J Paredes-Fuentes
- Institut de Recerca Sant Joan de Déu, Espluques de Llobregat, Barcelona, Spain
- Clinical Biochemistry Department, Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain
| | - Gemma Marfany
- Department of Genetics, Microbiology and Statistics, IBUB, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Institut de Recerca Sant Joan de Déu, Espluques de Llobregat, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instiuto de Salud Carlos III, Madrid, Spain
| | - Rafael Artuch
- Institut de Recerca Sant Joan de Déu, Espluques de Llobregat, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instiuto de Salud Carlos III, Madrid, Spain
- Clinical Biochemistry Department, Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain
| | - Daniel Grinberg
- Department of Genetics, Microbiology and Statistics, IBUB, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Institut de Recerca Sant Joan de Déu, Espluques de Llobregat, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instiuto de Salud Carlos III, Madrid, Spain
| | - Raquel Rabionet
- Department of Genetics, Microbiology and Statistics, IBUB, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Institut de Recerca Sant Joan de Déu, Espluques de Llobregat, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instiuto de Salud Carlos III, Madrid, Spain
| | - Susanna Balcells
- Department of Genetics, Microbiology and Statistics, IBUB, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Institut de Recerca Sant Joan de Déu, Espluques de Llobregat, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instiuto de Salud Carlos III, Madrid, Spain
| | - Roser Urreizti
- Institut de Recerca Sant Joan de Déu, Espluques de Llobregat, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instiuto de Salud Carlos III, Madrid, Spain
- Clinical Biochemistry Department, Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain
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Preimplantation Genetic Testing (PGT) and Prenatal Diagnosis of Schaaf-Yang Syndrome: A Report of Three Families and a Research on Genotype-Phenotype Correlations. J Clin Med 2023; 12:jcm12041688. [PMID: 36836222 PMCID: PMC9962152 DOI: 10.3390/jcm12041688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/10/2023] [Accepted: 02/17/2023] [Indexed: 02/22/2023] Open
Abstract
Schaaf-Yang Syndrome (SYS) is a genetic disorder caused by truncating pathogenic variants in the paternal allele of the maternally imprinted, paternally expressed gene MAGEL2 and is characterized by genital hypoplasia, neonatal hypotonia, developmental delay, intellectual disability, autism spectrum disorder (ASD), and other features. In this study, eleven SYS patients from three families were enrolled and comprehensive clinical features were gathered regarding each family. Whole-exome sequencing (WES) was performed for the definitive molecular diagnosis of the disease. Identified variants were validated using Sanger sequencing. Three couples underwent PGT for monogenic diseases (PGT-M) and/or a prenatal diagnosis. Haplotype analysis was performed to deduce the embryo's genotype by using the short tandem repeats (STRs) identified in each sample. The prenatal diagnosis results showed that the fetus in each case did not carry pathogenic variants, and all the babies of the three families were born at full term and were healthy. We also performed a review of SYS cases. In addition to the 11 patients in our study, a total of 127 SYS patients were included in 11 papers. We summarized all variant sites and clinical symptoms thus far, and conducted a genotype-phenotype correlation analysis. Our results also indicated that the variation in phenotypic severity may depend on the specific location of the truncating variant, suggestive of a genotype-phenotype association.
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Sanderson MR, Fahlman RP, Wevrick R. The N-terminal domain of the Schaaf-Yang syndrome protein MAGEL2 likely has a role in RNA metabolism. J Biol Chem 2021; 297:100959. [PMID: 34265304 PMCID: PMC8350409 DOI: 10.1016/j.jbc.2021.100959] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 06/22/2021] [Accepted: 07/11/2021] [Indexed: 02/08/2023] Open
Abstract
MAGEL2 encodes the L2 member of the melanoma-associated antigen gene (MAGE) protein family, truncating mutations of which can cause Schaaf-Yang syndrome, an autism spectrum disorder. MAGEL2 is also inactivated in Prader-Willi syndrome, which overlaps clinically and mechanistically with Schaaf-Yang syndrome. Studies to date have only investigated the C-terminal portion of the MAGEL2 protein, containing the MAGE homology domain that interacts with RING-E3 ubiquitin ligases and deubiquitinases to form protein complexes that modify protein ubiquitination. In contrast, the N-terminal portion of the MAGEL2 protein has never been studied. Here, we find that MAGEL2 has a low-complexity intrinsically disordered N-terminus rich in Pro-Xn-Gly motifs that is predicted to mediate liquid-liquid phase separation to form biomolecular condensates. We used proximity-dependent biotin identification (BioID) and liquid chromatography-tandem mass spectrometry to identify MAGEL2-proximal proteins, then clustered these proteins into functional networks. We determined that coding mutations analogous to disruptive mutations in other MAGE proteins alter these networks in biologically relevant ways. Proteins identified as proximal to the N-terminal portion of MAGEL2 are primarily involved in mRNA metabolic processes and include three mRNA N 6-methyladenosine (m6A)-binding YTHDF proteins and two RNA interference-mediating TNRC6 proteins. We found that YTHDF2 coimmunoprecipitates with MAGEL2, and coexpression of MAGEL2 reduces the nuclear accumulation of YTHDF2 after heat shock. We suggest that the N-terminal region of MAGEL2 may have a role in RNA metabolism and in particular the regulation of mRNAs modified by m6A methylation. These results provide mechanistic insight into pathogenic MAGEL2 mutations associated with Schaaf-Yang syndrome and related disorders.
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Affiliation(s)
- Matthea R Sanderson
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
| | - Richard P Fahlman
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada; Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
| | - Rachel Wevrick
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada.
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Pellikaan K, van Woerden GM, Kleinendorst L, Rosenberg AGW, Horsthemke B, Grosser C, van Zutven LJCM, van Rossum EFC, van der Lely AJ, Resnick JL, Brüggenwirth HT, van Haelst MM, de Graaff LCG. The Diagnostic Journey of a Patient with Prader-Willi-Like Syndrome and a Unique Homozygous SNURF-SNRPN Variant; Bio-Molecular Analysis and Review of the Literature. Genes (Basel) 2021; 12:genes12060875. [PMID: 34200226 PMCID: PMC8227738 DOI: 10.3390/genes12060875] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/25/2021] [Accepted: 05/27/2021] [Indexed: 12/11/2022] Open
Abstract
Prader–Willi syndrome (PWS) is a rare genetic condition characterized by hypotonia, intellectual disability, and hypothalamic dysfunction, causing pituitary hormone deficiencies and hyperphagia, ultimately leading to obesity. PWS is most often caused by the loss of expression of a cluster of genes on chromosome 15q11.2-13. Patients with Prader–Willi-like syndrome (PWLS) display features of the PWS phenotype without a classical PWS genetic defect. We describe a 46-year-old patient with PWLS, including hypotonia, intellectual disability, hyperphagia, and pituitary hormone deficiencies. Routine genetic tests for PWS were normal, but a homozygous missense variant NM_003097.3(SNRPN):c.193C>T, p.(Arg65Trp) was identified. Single nucleotide polymorphism array showed several large regions of homozygosity, caused by high-grade consanguinity between the parents. Our functional analysis, the ‘Pipeline for Rapid in silico, in vivo, in vitro Screening of Mutations’ (PRiSM) screen, showed that overexpression of SNRPN-p.Arg65Trp had a dominant negative effect, strongly suggesting pathogenicity. However, it could not be confirmed that the variant was responsible for the phenotype of the patient. In conclusion, we present a unique homozygous missense variant in SNURF-SNRPN in a patient with PWLS. We describe the diagnostic trajectory of this patient and the possible contributors to her phenotype in light of the current literature on the genotype–phenotype relationship in PWS.
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Affiliation(s)
- Karlijn Pellikaan
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands; (K.P.); (A.G.W.R.); (E.F.C.v.R.); (A.J.v.d.L.)
- Dutch Centre of Reference for Prader-Willi Syndrome, 3015 GD Rotterdam, The Netherlands
| | - Geeske M. van Woerden
- Department of Neuroscience, Erasmus University Medical Centre, 3015 GD Rotterdam, The Netherlands;
- The ENCORE Expertise Centre for Neurodevelopmental Disorders, Erasmus University Medical Centre, 3015 GD Rotterdam, The Netherlands
- Department of Clinical Genetics, Erasmus University Medical Centre, 3015 GD Rotterdam, The Netherlands; (L.J.C.M.v.Z.); (H.T.B.)
| | - Lotte Kleinendorst
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, 1081 HV Amsterdam, The Netherlands; (L.K.); (M.M.v.H.)
| | - Anna G. W. Rosenberg
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands; (K.P.); (A.G.W.R.); (E.F.C.v.R.); (A.J.v.d.L.)
- Dutch Centre of Reference for Prader-Willi Syndrome, 3015 GD Rotterdam, The Netherlands
| | - Bernhard Horsthemke
- Institute of Human Genetics, University Hospital Essen, University Duisburg-Essen, 45147 Essen, Germany; (B.H.); (C.G.)
| | - Christian Grosser
- Institute of Human Genetics, University Hospital Essen, University Duisburg-Essen, 45147 Essen, Germany; (B.H.); (C.G.)
- Praxis für Humangenetik Tübingen, 72076 Tuebingen, Germany
| | - Laura J. C. M. van Zutven
- Department of Clinical Genetics, Erasmus University Medical Centre, 3015 GD Rotterdam, The Netherlands; (L.J.C.M.v.Z.); (H.T.B.)
| | - Elisabeth F. C. van Rossum
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands; (K.P.); (A.G.W.R.); (E.F.C.v.R.); (A.J.v.d.L.)
- Obesity Center CGG, Erasmus MC, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands
| | - Aart J. van der Lely
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands; (K.P.); (A.G.W.R.); (E.F.C.v.R.); (A.J.v.d.L.)
| | - James L. Resnick
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA;
| | - Hennie T. Brüggenwirth
- Department of Clinical Genetics, Erasmus University Medical Centre, 3015 GD Rotterdam, The Netherlands; (L.J.C.M.v.Z.); (H.T.B.)
| | - Mieke M. van Haelst
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, 1081 HV Amsterdam, The Netherlands; (L.K.); (M.M.v.H.)
| | - Laura C. G. de Graaff
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands; (K.P.); (A.G.W.R.); (E.F.C.v.R.); (A.J.v.d.L.)
- Dutch Centre of Reference for Prader-Willi Syndrome, 3015 GD Rotterdam, The Netherlands
- The ENCORE Expertise Centre for Neurodevelopmental Disorders, Erasmus University Medical Centre, 3015 GD Rotterdam, The Netherlands
- Academic Centre for Growth Disorders, Erasmus MC Rotterdam, 3015 GD Rotterdam, The Netherlands
- Correspondence: ; Tel.: +31-618843010
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Ieda D, Negishi Y, Miyamoto T, Johmura Y, Kumamoto N, Kato K, Miyoshi I, Nakanishi M, Ugawa S, Oishi H, Saitoh S. Two mouse models carrying truncating mutations in Magel2 show distinct phenotypes. PLoS One 2020; 15:e0237814. [PMID: 32804975 PMCID: PMC7430741 DOI: 10.1371/journal.pone.0237814] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 08/02/2020] [Indexed: 12/14/2022] Open
Abstract
Schaaf-Yang syndrome (SYS) is a neurodevelopmental disorder caused by truncating variants in the paternal allele of MAGEL2, located in the Prader-Willi critical region, 15q11-q13. Although the phenotypes of SYS overlap those of Prader-Willi syndrome (PWS), including neonatal hypotonia, feeding problems, and developmental delay/intellectual disability, SYS patients show autism spectrum disorder and joint contractures, which are atypical phenotypes for PWS. Therefore, we hypothesized that the truncated Magel2 protein could potentially produce gain-of-function toxic effects. To test the hypothesis, we generated two engineered mouse models; one, an overexpression model that expressed the N-terminal region of Magel2 that was FLAG tagged with a strong ubiquitous promoter, and another, a genome-edited model that carried a truncating variant in Magel2 generated using the CRISPR/Cas9 system. In the overexpression model, all transgenic mice died in the fetal or neonatal period indicating embryonic or neonatal lethality of the transgene. Therefore, overexpression of the truncated Magel2 could show toxic effects. In the genome-edited model, we generated a mouse model carrying a frameshift variant (c.1690_1924del; p(Glu564Serfs*130)) in Magel2. Model mice carrying the frameshift variant in the paternal or maternal allele of Magel2 were termed Magel2P:fs and Magel2M:fs, respectively. The imprinted expression and spatial distribution of truncating Magel2 transcripts in the brain were maintained. Although neonatal Magel2P:fs mice were lighter than wildtype littermates, Magel2P:fs males and females weighed the same as their wildtype littermates by eight and four weeks of age, respectively. Collectively, the overexpression mouse model may recapitulate fetal or neonatal death, which are the severest phenotypes for SYS. In contrast, the genome-edited mouse model maintains genomic imprinting and distribution of truncated Magel2 transcripts in the brain, but only partially recapitulates SYS phenotypes. Therefore, our results imply that simple gain-of-function toxic effects may not explain the patho-mechanism of SYS, but rather suggest a range of effects due to Magel2 variants as in human SYS patients.
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Affiliation(s)
- Daisuke Ieda
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Yutaka Negishi
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Tomomi Miyamoto
- Department of Comparative and Experimental Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Yoshikazu Johmura
- Division of Cancer Cell Biology, Department of Cancer Biology, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Natsuko Kumamoto
- Department of Anatomy and Neuroscience, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Kohji Kato
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya Japan
| | - Ichiro Miyoshi
- Department of Comparative and Experimental Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Makoto Nakanishi
- Division of Cancer Cell Biology, Department of Cancer Biology, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Shinya Ugawa
- Department of Anatomy and Neuroscience, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Hisashi Oishi
- Department of Comparative and Experimental Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Shinji Saitoh
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
- * E-mail:
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Chen X, Ma X, Zou C. Phenotypic spectrum and genetic analysis in the fatal cases of Schaaf-Yang syndrome: Two case reports and literature review. Medicine (Baltimore) 2020; 99:e20574. [PMID: 32702813 PMCID: PMC7373511 DOI: 10.1097/md.0000000000020574] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
RATIONALE Schaaf-Yang syndrome, a rare imprinted hereditary disease caused by MAGEL2 variants, manifests as developmental delay/intellectual disability, neonatal hypotonia, feeding difficulties, contractures, and autism spectrum disorder. PATIENT CONCERNS Patient 1 and 2 were infant girls presenting facial dysmorphisms, contractures of interphalangeal joints, neonatal hypotonia, feeding difficulties, congenital heart diseases, and respiratory complications. Besides, Patient 2 presented with delayed psychomotor development. DIAGNOSIS Whole-exome sequencing was performed and heterozygous mutations of the MAGEL2 gene were detected in the patients. They were diagnosed as Schaaf-Yang syndrome. INTERVENTIONS The patients received supportive treatment including mechanical ventilation, parenteral nutrition and gastric tube feeding. OUTCOMES Whole-exome sequencing revealed de novo heterozygous c.1996dupC pathogenic mutations in the MAGEL2 gene in the 2 patients. They died due to respiratory failure at the age of 20 days and 98 days, respectively. LESSONS Our results indicate that MAGEL2 variants can cause congenital heart disease and fatal respiratory complications, broadening the phenotypic spectrum and adding to the fatal cases of Schaaf-Yang syndrome. We highly suggest that the MAGEL2 gene should be added to gene-panels or gene-filters in next-generation sequencing-based diagnostics, which is of great significance for early diagnosis and early intervention of Schaaf-Yang syndrome patients.
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Affiliation(s)
| | - Xiaolu Ma
- Department of Neonatal Intensive Care Unit, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang Province, China
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Gregory LC, Shah P, Sanner JRF, Arancibia M, Hurst J, Jones WD, Spoudeas H, Le Quesne Stabej P, Williams HJ, Ocaka LA, Loureiro C, Martinez-Aguayo A, Dattani MT. Mutations in MAGEL2 and L1CAM Are Associated With Congenital Hypopituitarism and Arthrogryposis. J Clin Endocrinol Metab 2019; 104:5737-5750. [PMID: 31504653 PMCID: PMC6916815 DOI: 10.1210/jc.2019-00631] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 07/18/2019] [Indexed: 12/29/2022]
Abstract
CONTEXT Congenital hypopituitarism (CH) is rarely observed in combination with severe joint contractures (arthrogryposis). Schaaf-Yang syndrome (SHFYNG) phenotypically overlaps with Prader-Willi syndrome, with patients also manifesting arthrogryposis. L1 syndrome, a group of X-linked disorders that include hydrocephalus and lower limb spasticity, also rarely presents with arthrogryposis. OBJECTIVE We investigated the molecular basis underlying the combination of CH and arthrogryposis in five patients. PATIENTS The heterozygous p.Q666fs*47 mutation in the maternally imprinted MAGEL2 gene, previously described in multiple patients with SHFYNG, was identified in patients 1 to 4, all of whom manifested growth hormone deficiency and variable SHFYNG features, including dysmorphism, developmental delay, sleep apnea, and visual problems. Nonidentical twins (patients 2 and 3) had diabetes insipidus and macrocephaly, and patient 4 presented with ACTH insufficiency. The hemizygous L1CAM variant p.G452R, previously implicated in patients with L1 syndrome, was identified in patient 5, who presented with antenatal hydrocephalus. RESULTS Human embryonic expression analysis revealed MAGEL2 transcripts in the developing hypothalamus and ventral diencephalon at Carnegie stages (CSs) 19, 20, and 23 and in the Rathke pouch at CS20 and CS23. L1CAM was expressed in the developing hypothalamus, ventral diencephalon, and hindbrain (CS19, CS20, CS23), but not in the Rathke pouch. CONCLUSION We report MAGEL2 and L1CAM mutations in four pedigrees with variable CH and arthrogryposis. Patients presenting early in life with this combined phenotype should be examined for features of SHFYNG and/or L1 syndrome. This study highlights the association of hypothalamo-pituitary disease with MAGEL2 and L1CAM mutations.
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Affiliation(s)
- Louise C Gregory
- Genetics and Genomic Medicine Programme, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Pratik Shah
- Great Ormond Street Hospital, London, United Kingdom
| | | | - Monica Arancibia
- Division de Pediatria, Escuela de Medicina, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - Jane Hurst
- NE Thames Genetics Service, Great Ormond Street Hospital, London, United Kingdom
| | - Wendy D Jones
- NE Thames Genetics Service, Great Ormond Street Hospital, London, United Kingdom
| | | | - Polona Le Quesne Stabej
- Genetics and Genomic Medicine Programme, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Hywel J Williams
- Genetics and Genomic Medicine Programme, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Louise A Ocaka
- Genetics and Genomic Medicine Programme, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Carolina Loureiro
- Division de Pediatria, Escuela de Medicina, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - Alejandro Martinez-Aguayo
- Division de Pediatria, Escuela de Medicina, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - Mehul T Dattani
- Genetics and Genomic Medicine Programme, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
- Great Ormond Street Hospital, London, United Kingdom
- Correspondence and Reprint Requests: Mehul T. Dattani, MD, Paediatric Endocrinology, Genetics and Genomic Medicine Programme, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, United Kingdom. E-mail:
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