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Zago S, Silvestri E, Arcangeli T, Calisesi M, Romeo C, Parmeggiani G, Parrini E, Cetica V, Guerrini R, Palicelli A, Bonasoni MP. Fetal Presentation of Walker-Warburg Syndrome with Compound Heterozygous POMT2 Missense Mutations. Fetal Pediatr Pathol 2023; 42:334-341. [PMID: 36048137 DOI: 10.1080/15513815.2022.2116620] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Background: Walker-Warburg syndrome (WWS) (OMIM #236670) is an autosomal recessive disorder characterized by congenital muscular dystrophy, hydrocephalus, cobblestone lissencephaly, and retinal dysplasia. The main genes involved are: POMT1, POMT2, POMGNT1, FKTN, LARGE1, and FKRP. Case report: We present a fetus with WWS showing at ultrasound severe triventricular hydrocephalus. Pregnancy was legally terminated at 21 weeks +2 days of gestation. In vivo and postmortem magnetic resonance revealed corpus callosum agenesis and cerebellar hypoplasia. Cobblestone lissencephaly was observed at post-mortem. Next generation sequencing (NGS) of 193 genes, performed on fetal DNA extracted from amniocytes, detected two heterozygous mutations in the POMT2 gene. The c.1238G > C p.(Arg413Pro) mutation was paternally inherited and is known to be pathogenic. The c.553G > A p.(Gly185Arg) mutation was maternally inherited and has not been previously described. Conclusion: Compound heterozygous mutations in the POMT2 gene caused a severe cerebral fetal phenotype diagnosed prenatally at midgestation allowing therapeutic pregnancy termination.
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Affiliation(s)
- Silvia Zago
- Unit of Pathology, AUSL della Romagna, St. Maria delle Croci Hospital, Ravenna, Italy
| | - Evelina Silvestri
- Division of Pathology, Unit of Fetal and Neonatal Pathology, San Camillo-Forlanini Hospital, Rome, Italy
| | - Tiziana Arcangeli
- Unit of Obstetrics and Gynecology, AUSL della Romagna, St. Maria delle Croci Hospital, Ravenna, Italy
| | - Marina Calisesi
- Unit of Obstetrics and Gynecology, AUSL della Romagna, St. Maria delle Croci Hospital, Ravenna, Italy
| | - Chiara Romeo
- Unit of Radiology, AUSL della Romagna, St. Maria delle Croci Hospital, Ravenna, Italy
| | - Giulia Parmeggiani
- Medical Genetics Unit, AUSL della Romagna, Ospedale Bufalini, Cesena, Italy
| | - Elena Parrini
- Pediatric Neurology, Neurogenetics, and Neurobiology Unit and Laboratories, Meyer Children's Hospital-University of Florence, Florence, Italy
| | - Valentina Cetica
- Pediatric Neurology, Neurogenetics, and Neurobiology Unit and Laboratories, Meyer Children's Hospital-University of Florence, Florence, Italy
| | - Renzo Guerrini
- Pediatric Neurology, Neurogenetics, and Neurobiology Unit and Laboratories, Meyer Children's Hospital-University of Florence, Florence, Italy
| | - Andrea Palicelli
- Pathology Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
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Vriend I, Oegema R. Genetic causes underlying grey matter heterotopia. Eur J Paediatr Neurol 2021; 35:82-92. [PMID: 34666232 DOI: 10.1016/j.ejpn.2021.09.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 09/21/2021] [Indexed: 11/15/2022]
Abstract
Grey matter heterotopia (GMH) can cause of seizures and are associated with a wide range of neurodevelopmental disorders and syndromes. They are caused by a failure of neuronal migration during fetal development, leading to clusters of neurons that have not reached their final destination in the cerebral cortex. We have performed an extensive literature search in Pubmed, OMIM, and Google scholar and provide an overview of known genetic associations with periventricular nodular heterotopia (PNVH), subcortical band heterotopia (SBH) and other subcortical heterotopia (SUBH). We classified the heterotopias as PVNH, SBH, SUBH or other and collected the genetic information, frequency, imaging features and salient features in tables for every subtype of heterotopia. This resulted in 105 PVNH, 16 SBH and 25 SUBH gene/locus associations, making a total of 146 genes and chromosomal loci. Our study emphasizes the extreme genetic heterogeneity underlying GMH. It will aid the clinician in establishing an differential diagnosis and eventually a molecular diagnosis in GMH patients. A diagnosis enables proper counseling of prognosis and recurrence risks, and enables individualized patient management.
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Affiliation(s)
- Ilona Vriend
- Department of Genetics, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Renske Oegema
- Department of Genetics, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands.
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El-Dessouky SH, Hosny H, Elarab AE, Issa MY. Prenatal presentation of Walker–Warburg syndrome with a POMT2 mutation: an extended fetal phenotype. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2020. [DOI: 10.1186/s43042-020-00093-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Walker–Warburg syndrome (WWS) is a rare, lethal, genetically, and clinically heterogeneous congenital muscular dystrophy resulting from defective glycosylation of α-dystroglycan (α-DG) and is associated with both cranial and ocular malformations. Prenatal detection of posterior fossa anomalies in association with hydrocephalus are nonspecific, however, an additional finding of eye anomalies are typical for WWS. The purpose of this report is to elucidate the pattern of associated malformations in a fetus with WWS born to 3rd degree consanguineously married couple. Additionally, the fetal ultrasonography revealed congenital heart disease, clenched hands, and talipes equinovarus; these findings have not been previously reported and represent an expansion of prenatal spectrum associated with WWS.
Case presentation
We report on a specific sonographic pattern of congenital anomalies including hydrocephalus, agenesis of corpus callosum, and Dandy–Walker malformation. Ocular abnormalities include microphthalmia, cataract, and an echoic structure suggestive of persistent primary vitreous. Other features include congenital heart disease, unilateral multicystic kidney, and previously unreported findings of bilateral clenched hands and talipes equinovarus. The molecular analysis detected a homozygous splicing mutation, c.924-2A>C, in the POMT2 gene; this variant segregated with the phenotype.
Conclusion
WWS syndrome has characteristic prenatal ultrasound findings which can improve the prenatal identification of this condition and help in guiding the molecular diagnosis and counseling. The detection of bilateral clenched hands and talipes equinovarus is a novel finding that further expands the phenotypic spectrum of WWS.
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Mohamadian M, Naseri M, Ghandil P, Bahrami A, Momen AA. The first report of two homozygous sequence variants in FKRP and SELENON genes associated with syndromic congenital muscular dystrophy in Iran: Further expansion of the clinical phenotypes. J Gene Med 2020; 22:e3265. [PMID: 32864802 DOI: 10.1002/jgm.3265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 07/11/2020] [Accepted: 08/22/2020] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Congenital muscular dystrophy (CMD) refers to hypotonia and delayed motor development that is manifested at or near the birth. Additional presentations have been observed in CMD syndromes. METHODS Thorough clinical examinations were performed on two unrelated Iranian families with typical symptoms of CMD and uncommon features such as intellectual disability and nephrolithiasis. The genomic DNA of probands were subjected to whole exome sequencing. Following the detection of candidate variants with a bioinformatic pipeline, the familial co-segregation analysis was carried out using polymerase chain reaction-based Sanger sequencing. RESULTS We identified a missense homozygous variant in the fukutin-related protein (FKRP) gene (c.968G>A, p.Arg323His) related to CMD-dystroglycanopathy type B5 (MDDGB5) and a frameshift homozygous variant in the selenoprotein N (SELENON) gene (c.1446delC, p.Asn483Thrfs*11) associated with congenital rigid-spine muscular dystrophy 1 (RSMD1), which were completely segregated with the phenotypes in the families. These variants were not found in either the 1000 Genomes Project or the Exome Aggregation Consortium. The present study provides the first report of these homozygous sequence variants in Iran. Moreover, our study was the first observation of nephrolithiasis in FKRP-related dystroglycanopathy and intellectual disability in SELENON-related myopathies. Based on in silico studies and molecular docking, these variations induced pathogenic effects on the proteins. CONCLUSIONS Our findings extend the genetic database of Iranian patients with CMD and, in general, the phenotypical spectrum of syndromic CMD. It is recommended to consider these variants for a more accurate clinical interpretation, prenatal diagnosis and genetic counseling in families with a history of CMD, especially in those combined with cognitive impairments or renal dysfunctions.
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Affiliation(s)
- Malihe Mohamadian
- Department of Molecular Medicine, Birjand University of Medical Sciences, Birjand, Iran
| | - Mohsen Naseri
- Cellular and Molecular Research Center, Birjand University of Medical Sciences, Birjand, Iran
| | - Pegah Ghandil
- Diabetes Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.,Department of Medical Genetics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Afsane Bahrami
- Cellular and Molecular Research Center, Birjand University of Medical Sciences, Birjand, Iran
| | - Ali Akbar Momen
- Department of Paediatric Neurology, Golestan Medical, Educational, and Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
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Arora V, Bijarnia-Mahay S, Kulshreshtra S, Singh K, Puri RD, Verma IC. Prenatal presentation of a rare genetic disorder: a clinical, autopsy and molecular correlation. AUTOPSY AND CASE REPORTS 2019; 9:e2019124. [PMID: 31641664 PMCID: PMC6771443 DOI: 10.4322/acr.2019.124] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 08/27/2019] [Indexed: 12/14/2022] Open
Abstract
Walker Warburg syndrome (WWS) lies at the severe end of the spectrum of the congenital muscular dystrophies. WWS is a congenital disorder of the O-glycosylation that disrupts in the post-translation modification of dystroglycan proteins. WWS is characterized by the involvement of the central nervous system and rarely by multisystem involvement. Next-generation sequencing discovered that multiple genes are associated with this disorder. FKTN is the rarest cause of WWS. We describe a clinical-autopsy report of a molecularly- confirmed WWS case presenting with ventriculomegaly, agenesis of the corpus callosum with a novel phenotype of Dandy-Walker malformation and unilateral multi-cystic kidney. The whole-exome sequencing confirmed a homozygous variant (c.411C>A) in the FKTN gene with a premature termination codon. This case emphasizes the importance of detailed postnatal phenotyping through an autopsy in any pregnancy with antenatally identified malformations. Obstetricians, pediatricians as well as fetal medicine experts need to counsel the parents and focus on preserving the appropriate sample for genetic testing. WWS, though rare deserves testing especially in the presence of positive family history. Dandy-Walker malformation is a novel feature and expands the phenotypic spectrum.
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Affiliation(s)
- Veronica Arora
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital. New Delhi, India
| | - Sunita Bijarnia-Mahay
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital. New Delhi, India
| | - Samarth Kulshreshtra
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital. New Delhi, India
| | - Kanika Singh
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital. New Delhi, India
| | - Ratna Dua Puri
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital. New Delhi, India
| | - Ishwar Chandar Verma
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital. New Delhi, India
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Bai L, Kovach A, You Q, Kenny A, Li H. Structure of the eukaryotic protein O-mannosyltransferase Pmt1-Pmt2 complex. Nat Struct Mol Biol 2019; 26:704-711. [PMID: 31285605 PMCID: PMC6684406 DOI: 10.1038/s41594-019-0262-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 05/29/2019] [Indexed: 12/24/2022]
Abstract
In eukaryotes, a nascent peptide entering the endoplasmic reticulum (ER) is scanned by two Sec61-translocon-associated large membrane machines for protein N-glycosylation and protein O-mannosylation, respectively. While the structure of the eight-protein oligosaccharyltransferase complex has been determined recently, the structures of mannosyltransferases of the PMT family, which are an integral part of ER protein homeostasis, are still unknown. Here we report cryo-EM structures of the S. cerevisiae Pmt1–Pmt2 complex bound to a donor and an acceptor peptide at 3.2-Å resolution, showing that each subunit contains 11 transmembrane helices and a lumenal β-trefoil fold termed the MIR domain. The structures reveal the substrate recognition model and confirm an inverting mannosyl-transferring reaction mechanism by the enzyme complex. Furthermore, we found that the transmembrane domains of Pmt1 and Pmt2 share a structural fold with the catalytic subunits of oligosaccharyltransferases, confirming a previously proposed evolutionary relationship between protein O-mannosylation and protein N-glycosylation.
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Affiliation(s)
- Lin Bai
- Structural Biology Program, Van Andel Research Institute, Grand Rapids, MI, USA
| | - Amanda Kovach
- Structural Biology Program, Van Andel Research Institute, Grand Rapids, MI, USA
| | - Qinglong You
- Structural Biology Program, Van Andel Research Institute, Grand Rapids, MI, USA
| | - Alanna Kenny
- Structural Biology Program, Van Andel Research Institute, Grand Rapids, MI, USA
| | - Huilin Li
- Structural Biology Program, Van Andel Research Institute, Grand Rapids, MI, USA.
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Hu P, Yuan L, Deng H. Molecular genetics of the POMT1-related muscular dystrophy-dystroglycanopathies. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2018; 778:45-50. [PMID: 30454682 DOI: 10.1016/j.mrrev.2018.09.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 08/06/2018] [Accepted: 09/10/2018] [Indexed: 01/22/2023]
Abstract
Protein O-mannosyltransferase 1 (POMT1) is a critical enzyme participating in the first step of protein O-mannosylation. Mutations in the coding gene, POMT1, have been described to be related to a series of autosomal recessive disorders associated with defective alpha-dystroglycan glycosylation, later termed muscular dystrophy-dystroglycanopathies (MDDGs). MDDGs are characterized by a broad phenotypic spectrum of congenital muscular dystrophy or later-onset limb-girdle muscular dystrophy, accompanied by variable degrees of intellectual disability, brain defects, and ocular abnormalities. To date, at least 76 disease-associated mutations in the POMT1 gene, including missense, nonsense, splicing, deletion, insertion/duplication, and insertion-deletion mutations, have been reported in the literature. In this review, we highlight the present knowledge of the identified disease-associated POMT1 gene mutations and genetic animal models related to the POMT1 gene. This review may help further normative classification of phenotypes, assist in definite clinical and genetic diagnoses, and genetic counseling, and may comprehensively improve our understanding of the basis of complex phenotypes and possible pathogenic mechanisms involved.
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Affiliation(s)
- Pengzhi Hu
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha, PR China; Department of Radiology, the Third Xiangya Hospital, Central South University, Changsha, PR China
| | - Lamei Yuan
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha, PR China.
| | - Hao Deng
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha, PR China.
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8
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Finsterer J. Phenotypic heterogeneity of POMT2
gene variants. Am J Med Genet A 2018; 176:743-745. [DOI: 10.1002/ajmg.a.38588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 11/03/2017] [Accepted: 12/01/2017] [Indexed: 11/06/2022]
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