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Kovalskaia VA, Kungurtseva AL, Bostanova FM, Vasiliev PA, Tabakov VY, Orlova MD, Povolotskaya IS, Novoselova OG, Bikanov RA, Akhyamova MA, Tikhonovich YV, Popovich AV, Vitebskaya AV, Dadali EL, Ryzhkova OP. The Genetic Basis of the First Patient with Wiedemann-Rautenstrauch Syndrome in the Russian Federation. Genes (Basel) 2024; 15:180. [PMID: 38397171 PMCID: PMC10887809 DOI: 10.3390/genes15020180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/15/2024] [Accepted: 01/18/2024] [Indexed: 02/25/2024] Open
Abstract
Bi-allelic pathogenic variations within POLR3A have been associated with a spectrum of hereditary disorders. Among these, a less frequently observed condition is Wiedemann-Rautenstrauch syndrome (WRS), also known as neonatal progeroid syndrome. This syndrome typically manifests neonatally and is characterized by growth retardation, evident generalized lipodystrophy with distinctively localized fat accumulations, sparse scalp hair, and atypical facial features. Our objective was to elucidate the underlying molecular mechanisms of Wiedemann-Rautenstrauch syndrome (WRS). In this study, we present a clinical case of a 7-year-old female patient diagnosed with WRS. Utilizing whole-exome sequencing (WES), we identified a novel missense variant c.3677T>C (p.Leu1226Pro) in the POLR3A gene (NM_007055.4) alongside two cis intronic variants c.1909+22G>A and c.3337-11T>C. Via the analysis of mRNA derived from fibroblasts, we reconfirmed the splicing-affecting nature of the c.3337-11T>C variant. Furthermore, our investigation led to the reclassification of the c.3677T>C (p.Leu1226Pro) variant as a likely pathogenic variant. Therefore, this is the first case demonstrating the molecular genetics of a patient with Wiedemann-Rautenstrauch syndrome from the Russian Federation. A limited number of clinical cases have been documented until this moment; therefore, broadening the linkage between phenotype and molecular changes in the POLR3A gene will significantly contribute to the comprehensive understanding of the molecular basis of POLR3A-related disorders.
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Affiliation(s)
| | - Anastasiia L. Kungurtseva
- Pediatric Endocrinology Department, I.M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia; (A.L.K.)
| | | | - Peter A. Vasiliev
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (V.A.K.)
| | | | - Mariia D. Orlova
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (V.A.K.)
| | | | | | | | | | - Yulia V. Tikhonovich
- Pediatric Endocrinology Department, I.M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia; (A.L.K.)
| | - Anastasiia V. Popovich
- Pediatric Endocrinology Department, I.M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia; (A.L.K.)
| | - Alisa V. Vitebskaya
- Pediatric Endocrinology Department, I.M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia; (A.L.K.)
| | - Elena L. Dadali
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (V.A.K.)
| | - Oxana P. Ryzhkova
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (V.A.K.)
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Colona VL, Bertini E, Digilio MC, D’Amico A, Novelli A, Pro S, Pisaneschi E, Nicita F. A New Case of Autosomal-Dominant POLR3B-Related Disorder: Widening Genotypic and Phenotypic Spectrum. Brain Sci 2023; 13:1567. [PMID: 38002527 PMCID: PMC10670162 DOI: 10.3390/brainsci13111567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 11/06/2023] [Accepted: 11/07/2023] [Indexed: 11/26/2023] Open
Abstract
POLR3B encodes the RPC2 subunit of RNA polymerase III. Pathogenic variants are associated with biallelic hypomyelinating leukodystrophy belonging to the POLR-related disorders. Recently, the association with dominant demyelinating neuropathy, classified as Charcot-Marie-Tooth syndrome type 1I (CMT1I), has been reported as well. Here we report on an additional patient presenting with developmental delay and generalized epilepsy, followed by the onset of mild pyramidal and cerebellar signs, vertical gaze palsy and subclinical demyelinating polyneuropathy. A new heterozygous de novo missense variant, c.1297C > G, p.Arg433Gly, in POLR3B was disclosed via trio-exome sequencing. In silico analysis confirms the hypothesis on the variant pathogenicity. Our research broadens both the genotypic and phenotypic spectrum of the autosomal-dominant POLR3B-related condition.
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Affiliation(s)
- Vito Luigi Colona
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, 00133 Rome, Italy;
- Laboratory of Medical Genetics, Translational Cytogenomics Research Unit, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (A.N.); (E.P.)
| | - Enrico Bertini
- Unit of Neuromuscular and Neurodegenerative Disease, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (E.B.); (A.D.)
| | - Maria Cristina Digilio
- Genetics and Rare Disease Research Division, Bambino Gesù Children Hospital, IRCCS, 00165 Rome, Italy;
- Medical Genetics Unit, Bambino Gesù Children Hospital, IRCCS, 00165 Rome, Italy
| | - Adele D’Amico
- Unit of Neuromuscular and Neurodegenerative Disease, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (E.B.); (A.D.)
| | - Antonio Novelli
- Laboratory of Medical Genetics, Translational Cytogenomics Research Unit, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (A.N.); (E.P.)
| | - Stefano Pro
- Developmental Neurology Unit, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy;
| | - Elisa Pisaneschi
- Laboratory of Medical Genetics, Translational Cytogenomics Research Unit, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (A.N.); (E.P.)
| | - Francesco Nicita
- Unit of Neuromuscular and Neurodegenerative Disease, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (E.B.); (A.D.)
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Sun L, Lin W, Meng H, Zhang W, Hou S. A Chinese patient with POLR3A-related leukodystrophy: a case report and literature review. Front Neurol 2023; 14:1269237. [PMID: 37965164 PMCID: PMC10641775 DOI: 10.3389/fneur.2023.1269237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 10/10/2023] [Indexed: 11/16/2023] Open
Abstract
Background Leukodystrophies are hereditary white matter diseases characterized by genetic polymorphisms and considerable phenotypic variability. They can be classified into myelin and non-myelin malformations. These diseases are rare, affecting 1 out of 250,000-500,000 individuals and can manifest at any age. A subtype of leukodystrophy, associated with missense mutations in the RNA polymerase subunit III (POLR3A) gene, is inherited in an autosomal recessive manner. Case report We report and analyse a case of a 34-year-old female who presented with ataxia. Magnetic Resonance Imaging (MRI) of the brain revealed demyelinating lesions in the white matter. Genetic testing identified the c.4044C > G and c.1186-2A > G variants in the POLR3A gene. The patient was diagnosed with hypomyelinating leukodystrophy type 7 and received neurotrophic and symptomatic supportive therapy. However, after 1 month of follow-up, there was no improvement in her symptoms. Conclusion POLR3A-induced leukodystrophy is relatively rare and not well understood, making it challenging to diagnose and easy to overlook. The prognosis for this disease is generally poor, significantly impacting the quality of life of affected individuals. Currently, no cure is available for this condition, and treatment is limited to managing symptoms. Further research into new treatment methods for POLR3A-induced leukodystrophy is imperative to improve the quality of life and potentially extend the life expectancy of patients.
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Affiliation(s)
| | | | | | | | - Shuai Hou
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
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4
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Yang H, Wu Z, Li X, Huang Y, Li J, He F, Feng L, Xiao B, Tang W. A novel variant of the POLR3A gene in a Chinese patient with POLR3-related leukodystrophy. Neurol Sci 2023; 44:3363-3368. [PMID: 36988728 DOI: 10.1007/s10072-023-06767-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Accepted: 03/19/2023] [Indexed: 03/30/2023]
Abstract
BACKGROUND POLR3-related leukodystrophy is a group of rare neurodegenerative disorders characterized by degeneration of the white matter with different combinations of major clinical features. CASE An 18-year-old lady was admitted for no menstruation since childhood. She gradually developed slight symptoms, such as choking after drinking water and unsteady walking in the last 2 years. Furthermore, her test scores and response capability were far lower than that of her peers. Physical examination revealed her to be of a slightly short stature, with stiff expressions and bilateral breast enlargement. She revealed clumsy movements when examined for ataxia, with an SARA score of 9. FINDINGS The laboratory data revealed a decreased level of estradiol, FSH, and LH, with a MoCA score of 7. Conventional karyotype analysis revealed a 46 XX 9qh + karyotype. Ultrasound indicated primordial uterus (19 × 11 × 10 mm). Brain MRI showed bilateral cerebral hemisphere myelin dysplasia, brain atrophy, thin corpus callosum, and small pituitary gland with uneven reinforcement and enlarged ventricles. Exome sequencing exhibited two missense mutations in the POLR3A gene (c.3013C > T and c.1757C > T), which were inherited from her mother and father, respectively. CONCLUSION Collectively, we identified novel compound heterozygous mutations of the POLR3A gene that caused POLR3A-related hypomyelinating leukodystrophy with hypogonadism in the patient combined with the clinical presentation, MRI brain pattern, and medical exome sequencing. TEACHING POINTS The complexity of clinical phenotypes and heterogeneity of genotypes raise new challenges in genetic diagnoses. This study will further aid our understanding of POLR3A-related leukodystrophy and promote further analysis of phenotype-genotype correlations of related diseases.
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Affiliation(s)
- Haojun Yang
- Department of Neurology, Xiangya Hospital of Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Zhongling Wu
- Department of Neurology, Xiangya Hospital of Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- Department of Clinical Nursing Teaching and Research Section, Xiangya Hospital, Central South University, Changsha, China
| | - Xiaolei Li
- Laizhou People's Hospital, Yantai, China
| | - Yuanxin Huang
- Department of Neurology, Xiangya Hospital of Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- Department of Clinical Nursing Teaching and Research Section, Xiangya Hospital, Central South University, Changsha, China
| | - Jing Li
- Department of Neurology, Xiangya Hospital of Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Fang He
- Department of Pediatric, Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Li Feng
- Department of Neurology, Xiangya Hospital of Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- Department of Neurology, Xiangya Hospital, Central South University (Jiangxi Branch), Nanchang, 330000, Jiangxi, China
| | - Bo Xiao
- Department of Neurology, Xiangya Hospital of Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Weiting Tang
- Department of Neurology, Xiangya Hospital of Central South University, Changsha, Hunan, China.
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.
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Buyukyilmaz G, Erozan Cavdarlı B, Toksoy Adiguzel K, Adiguzel M, Kasapkara CS, Gurbuz F, Boyraz M, Gurkas E. The First Case of 4H Syndrome with Type 1 Diabetes Mellitus. J Clin Res Pediatr Endocrinol 2023. [PMID: 36974356 DOI: 10.4274/jcrpe.galenos.2023.2023-1-15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/29/2023] Open
Abstract
4H syndrome is a rare progressive hypomyelinating leukodystrophy. Hypomyelination, hypodontia, and hypogonadotropic hypogonadism are the 3 classic features of 4H syndrome. Biallelic pathogenic variants in POLR3A, POLR3B, POLR1C, and POLR3K gene cause 4H leukodystrophy. Herein, we present clinical features in two siblings with 4H syndrome. The first patient (16 years) presented hypogonadotropic hypogonadism, euthyroid Hashimoto's thyroiditis and type 1 diabetes mellitus. The second patient (13.5 years) showed normal physical, biochemical and hormonal examination at presentation. It was learned that he was followed up for epilepsy between the ages of 6 months and 6 years, his epilepsy medication was discontinued at the age of 6, and he did not have seizure again. T2-weighted magnetic resonance images showed increased signal intensity secondary to hypomyelination at patients. They were subsequently found to have homozygous mutation in the POLR3A gene. 4H syndrome may present with neurological and non-neurological findings in addition to classic features of 4H syndrome. Progressive neurological deterioration may occur and endocrine dysfunction may be progressive. Although multipl endocrine abnormalities associated with this disorder have been reported to date, a case accompanied by type 1 DM has not been seen in the literature. We do not know exactly whether this is coinsidans or the expansion of the phenotype. So that reporting such cases helps to determine the appropriate genotype-phenotype correlation in patients.
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Affiliation(s)
- Gonul Buyukyilmaz
- Department of Pediatric Endocrinology, Ankara City Hospital, Ankara, Turkey
| | | | | | - Mehmet Adiguzel
- Department of Radiology, Ankara University School of Medicine, Ankara, Turkey
| | - Cigdem Seher Kasapkara
- Department of Pediatric Metabolism and Nutrition, Ankara Yildirim Beyazit University Faculty of Medicine, Ankara, Turkey
| | - Fatih Gurbuz
- Department of Pediatric Endocrinology, Ankara City Hospital, Ankara, Turkey
| | - Mehmet Boyraz
- Department of Pediatric Endocrinology, Ankara City Hospital, Ankara, Turkey
| | - Esra Gurkas
- Department of Pediatric Neurology, Ankara Yildirim Beyazit University Faculty of Medicine, Ankara, Turkey
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Zea Vera A, Bruce A, Larsh TR, Jordan Z, Brüggemann N, Westenberger A, Espay AJ, Gilbert DL, Wu SW. Spectrum of Pediatric to Early Adulthood POLR3A-Associated Movement Disorders. Mov Disord Clin Pract 2023; 10:316-322. [PMID: 36825045 PMCID: PMC9941928 DOI: 10.1002/mdc3.13635] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 11/14/2022] [Accepted: 11/23/2022] [Indexed: 12/12/2022] Open
Abstract
Background POLR3A pathogenic variants are associated with hypomyelination, hypodontia, hypogonadism, and movement disorders. Cases We describe the range of movement disorders seen in six patients (four female, two male) with POLR3A variants [three novel (c.2214del, c.3775G>A, c.3905G>T) and six previously reported (c.760C>T, c.1771-7C>G, c.1909+22G>A, c.2005C>T, c.2422C>T, c.3337-11T>C)]. Patient 1 presented with a neonatal progeroid syndrome and developed parkinsonism, dystonia, ataxia, and spasticity. Patient 2 presented with infant-onset rapidly progressive chorea, and dystonia. Three patients (patients 3, 5, 6) presented predominantly with ataxia in combination with spasticity and dystonia. Patient 4 developed segmental dystonia during adolescence and ataxia in early adulthood. Four patients had vertical gaze impairment. The most common brain MRI abnormality was T2-weighted/FLAIR hyperintensity of the superior cerebellar peduncles and midbrain. Conclusion POLR3A-related disorders exhibit significant phenotypic pleomorphism. Vertical gaze dysfunction and T2-weighted/FLAIR hyperintensity of the superior cerebellar peduncles and midbrain may be useful signs suggestive of this condition.
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Affiliation(s)
- Alonso Zea Vera
- Department of NeurologyChildren's National HospitalWashingtonDCUSA
- Department of NeurologyGeorge Washington University School of Medicine & Health SciencesWashingtonDCUSA
| | - Adrienne Bruce
- Department of PediatricsPrisma HealthGreenvilleSouth CarolinaUSA
- University of South Carolina School of Medicine GreenvilleGreenvilleSouth CarolinaUSA
| | - Travis R. Larsh
- Division of NeurologyCincinnati Children's Hospital Medical CenterCincinnatiOhioUSA
- Department of PediatricsUniversity of Cincinnati College of MedicineCincinnatiOhioUSA
| | - Zachary Jordan
- Department of NeurologyUniversity of Cincinnati Gardner Neuroscience InstituteCincinnatiOhioUSA
| | - Norbert Brüggemann
- Institute of NeurogeneticsUniversity of LübeckLübeckGermany
- Department of NeurologyUniversity of LübeckLübeckGermany
| | | | - Alberto J. Espay
- Department of NeurologyUniversity of Cincinnati Gardner Neuroscience InstituteCincinnatiOhioUSA
| | - Donald L. Gilbert
- Division of NeurologyCincinnati Children's Hospital Medical CenterCincinnatiOhioUSA
- Department of PediatricsUniversity of Cincinnati College of MedicineCincinnatiOhioUSA
| | - Steve W. Wu
- Division of NeurologyCincinnati Children's Hospital Medical CenterCincinnatiOhioUSA
- Department of PediatricsUniversity of Cincinnati College of MedicineCincinnatiOhioUSA
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Musumeci A, Calì F, Scuderi C, Vinci M, Vitello GA, Musumeci SA, Chiavetta V, Federico C, Amore G, Saccone S, Di Rosa G, Nicotera AG. Identification of a Novel Missense Mutation of POLR3A Gene in a Cohort of Sicilian Patients with Leukodystrophy. Biomedicines 2022; 10:biomedicines10092276. [PMID: 36140376 PMCID: PMC9496502 DOI: 10.3390/biomedicines10092276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 09/09/2022] [Accepted: 09/12/2022] [Indexed: 12/02/2022] Open
Abstract
Recessive mutations in the POLR3A gene cause POLR3-HLD (the second-most-common form of childhood-onset hypomyelinating leukodystrophy), a neurodegenerative disorder featuring deficient cerebral myelin formation. To date, more than 140 POLR3A (NM_007055.3) missense mutations are related to the pathogenesis of POLR3-related leukodystrophy and spastic ataxia. Herein, in a cohort of five families from Sicily (Italy), we detected two cases of patients affected by POLR3-related leukodystrophy, one due to a compound heterozygous mutation in the POLR3A gene, including a previously undescribed missense mutation (c.328A > G (p.Lys110Glu)). Our study used an in-house NGS gene panel comprising 41 known leukodystrophy genes. Successively, we used a predictive test supporting the missense mutation as causative of disease, thus this mutation can be considered “Likely Pathogenic” and could be as a new pathogenetic mutation of the POLR3A gene causing a severe form of POLR3-HLD.
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Affiliation(s)
- Antonino Musumeci
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy
| | - Francesco Calì
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy
| | - Carmela Scuderi
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy
| | - Mirella Vinci
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy
| | | | | | - Valeria Chiavetta
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy
| | - Concetta Federico
- Department Biological, Geological and Environmental Sciences, University of Catania, Via Androne 81, 95124 Catania, Italy
| | - Greta Amore
- Department of Human Pathology of the Adult and Developmental Age, “Gaetano Barresi” University of Messina, Via Consolare Valeria 1, 98125 Messina, Italy
| | - Salvatore Saccone
- Department Biological, Geological and Environmental Sciences, University of Catania, Via Androne 81, 95124 Catania, Italy
- Correspondence:
| | - Gabriella Di Rosa
- Department of Human Pathology of the Adult and Developmental Age, “Gaetano Barresi” University of Messina, Via Consolare Valeria 1, 98125 Messina, Italy
| | - Antonio Gennaro Nicotera
- Department of Human Pathology of the Adult and Developmental Age, “Gaetano Barresi” University of Messina, Via Consolare Valeria 1, 98125 Messina, Italy
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Sawaguchi S, Tago K, Oizumi H, Ohbuchi K, Yamamoto M, Mizoguchi K, Miyamoto Y, Yamauchi J. Hypomyelinating Leukodystrophy 7 (HLD7)-Associated Mutation of POLR3A Is Related to Defective Oligodendroglial Cell Differentiation, Which Is Ameliorated by Ibuprofen. Neurol Int 2021; 14:11-33. [PMID: 35076634 PMCID: PMC8788570 DOI: 10.3390/neurolint14010002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/14/2021] [Accepted: 12/21/2021] [Indexed: 01/13/2023] Open
Abstract
Hypomyelinating leukodystrophy 7 (HLD7) is an autosomal recessive oligodendroglial cell-related myelin disease, which is associated with some nucleotide mutations of the RNA polymerase 3 subunit a (polr3a) gene. POLR3A is composed of the catalytic core of RNA polymerase III synthesizing non-coding RNAs, such as rRNA and tRNA. Here, we show that an HLD7-associated nonsense mutation of Arg140-to-Ter (R140X) primarily localizes POLR3A proteins as protein aggregates into lysosomes in mouse oligodendroglial FBD-102b cells, whereas the wild type proteins are not localized in lysosomes. Expression of the R140X mutant proteins, but not the wild type proteins, in cells decreased signaling through the mechanistic target of rapamycin (mTOR), controlling signal transduction around lysosomes. While cells harboring the wild type constructs exhibited phenotypes with widespread membranes with myelin marker protein expression following the induction of differentiation, cells harboring the R140X mutant constructs did not exhibit them. Ibuprofen, a non-steroidal anti-inflammatory drug (NSAID), which is also known as an mTOR signaling activator, ameliorated defects in differentiation with myelin marker protein expression and the related signaling in cells harboring the R140X mutant constructs. Collectively, HLD7-associated POLR3A mutant proteins are localized in lysosomes where they decrease mTOR signaling, inhibiting cell morphological differentiation. Importantly, ibuprofen reverses undifferentiated phenotypes. These findings may reveal some of the pathological mechanisms underlying HLD7 and their amelioration at the molecular and cellular levels.
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Affiliation(s)
- Sui Sawaguchi
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan; (S.S.); (Y.M.)
| | - Kenji Tago
- Department of Biochemistry, Jichi Medical University, Shimotsuke 321-0498, Japan;
| | - Hiroaki Oizumi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (M.Y.); (K.M.)
| | - Katsuya Ohbuchi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (M.Y.); (K.M.)
| | - Masahiro Yamamoto
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (M.Y.); (K.M.)
| | - Kazushige Mizoguchi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (M.Y.); (K.M.)
| | - Yuki Miyamoto
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan; (S.S.); (Y.M.)
- Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535, Japan
| | - Junji Yamauchi
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan; (S.S.); (Y.M.)
- Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535, Japan
- Correspondence: ; Tel.: +81-42-676-7164; Fax: +81-42-676-8841
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9
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Sytsma TM, Chen DH, Rolf B, Dorschner M, Jayadev S, Keene CD, Zhang J, Bird TD, Latimer CS. Spinal cord-predominant neuropathology in an adult-onset case of POLR3A-related spastic ataxia. Neuropathology 2021; 42:58-65. [PMID: 34753215 PMCID: PMC8810698 DOI: 10.1111/neup.12775] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 07/30/2021] [Accepted: 07/30/2021] [Indexed: 12/30/2022]
Abstract
Biallelic mutations in POLR3A have been associated with childhood‐onset hypomyelinating leukodystrophies and adolescent‐to‐adult‐onset spastic ataxia, the latter of which has been linked to the intronic variant c.1909 + 22G>A. We report a case of adult‐onset spastic ataxia in a 75‐year‐old man, being a compound heterozygous carrier of this variant, whose brain and spinal cord were for the first time investigated by neuropathological examination. We describe prominent degeneration of the posterior columns, spinocerebellar tracts, and anterior corticospinal tracts of the spinal cord in a pattern resembling Friedreich's ataxia, with a notable lack of significant white matter pathology throughout the brain, in marked contrast with childhood‐onset cases. Immunohistochemical examination for the POLR3A protein demonstrated no apparent differences in localization or staining intensity between the proband and an age‐matched control subject. We demonstrate the clinicopathologic description of POLR3A‐related neurodegenerative disease and also mention the differential diagnosis of the childhood‐onset hypomyelinating leukodystrophy and late‐onset spastic ataxia phenotypes.
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Affiliation(s)
- Trevor M Sytsma
- Neuropathology Division, Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Dong-Hui Chen
- Department of Neurology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Bradley Rolf
- Division of Medical Genetics, Department of Medicine, University of Washington School of Medicine, Seattle, Washington, USA
| | - Michael Dorschner
- Division of Medical Genetics, Department of Medicine, University of Washington School of Medicine, Seattle, Washington, USA
| | - Suman Jayadev
- Neuropathology Division, Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA.,Department of Neurology, University of Washington School of Medicine, Seattle, Washington, USA.,Division of Medical Genetics, Department of Medicine, University of Washington School of Medicine, Seattle, Washington, USA
| | - C Dirk Keene
- Neuropathology Division, Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Jing Zhang
- Neuropathology Division, Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Thomas D Bird
- Department of Neurology, University of Washington School of Medicine, Seattle, Washington, USA.,Division of Medical Genetics, Department of Medicine, University of Washington School of Medicine, Seattle, Washington, USA.,Geriatric Research Education and Clinical Center, VA Puget Sound Health Care System, Seattle, Washington, USA
| | - Caitlin S Latimer
- Neuropathology Division, Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
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10
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Lessel D, Rading K, Campbell SE, Thiele H, Altmüller J, Gordon LB, Kubisch C. A novel homozygous synonymous variant further expands the phenotypic spectrum of POLR3A-related pathologies. Am J Med Genet A 2021; 188:216-223. [PMID: 34611991 DOI: 10.1002/ajmg.a.62525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/21/2021] [Accepted: 09/06/2021] [Indexed: 12/18/2022]
Abstract
Pathogenic biallelic variants in POL3RA have been associated with different disorders characterized by progressive neurological deterioration. These include the 4H leukodystrophy syndrome (hypomyelination, hypogonadotropic hypogonadism, and hypodontia) and adolescent-onset progressive spastic ataxia, as well as Wiedemann-Rautenstrauch syndrome (WRS), a recognizable neonatal progeroid syndrome. The phenotypic differences between these disorders are thought to occur mainly due to different functional effects of underlying POLR3A variants. Here we present the detailed clinical course of a 37-year-old woman in whom we identified a homozygous synonymous POLR3A variant c.3336G>A resulting in leaky splicing r.[3336ins192, =, 3243_3336del94]. She presented at birth with intrauterine growth retardation, lipodystrophy, muscular hypotonia, and several WRS-like facial features, albeit without sparse hair and prominent scalp veins. She had no signs of developmental delay or intellectual disability. Over the years, above characteristic facial features, she showed severe postnatal growth retardation, global lipodystrophy, joint contractures, thoracic hypoplasia, scoliosis, anodontia, spastic quadriplegia, bilateral hearing loss, aphonia, hypogonadotropic hypogonadism, and cerebellar peduncles hyperintensities in brain imaging. These manifestations partially overlap the clinical features of the previously reported POLR3A-associated disorders, mostly mimicking the WRS. Thus, our study expands the POLR3A-mediated phenotypic spectrum and suggests existence of a phenotypic continuum underlying biallelic POLR3A variants.
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Affiliation(s)
- Davor Lessel
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Katrin Rading
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Susan E Campbell
- Center for Gerontology and Healthcare Research, Brown University, Providence, Rhode Island, USA
| | - Holger Thiele
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Janine Altmüller
- Cologne Center for Genomics, University of Cologne, Cologne, Germany.,Berlin Institute of Health, Charité-Universitätsmedizin Berlin, Core Facility Genomics, Berlin, Germany.,The Genomics unit, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Leslie B Gordon
- Department of Pediatrics, Division of Genetics, Hasbro Children's Hospital, Providence, Rhode Island, USA.,Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA.,Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Christian Kubisch
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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11
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Di Donato I, Gallo A, Ricca I, Fini N, Silvestri G, Gurrieri F, Cirillo M, Cerase A, Natale G, Matrone F, Riso V, Melone MAB, Tessa A, De Michele G, Federico A, Filla A, Dotti MT, Santorelli FM. POLR3A variants in hereditary spastic paraparesis and ataxia: clinical, genetic, and neuroradiological findings in a cohort of Italian patients. Neurol Sci 2021; 43:1071-1077. [PMID: 34296356 PMCID: PMC8789690 DOI: 10.1007/s10072-021-05462-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 07/03/2021] [Indexed: 11/01/2022]
Abstract
Mutations in POLR3A are characterized by high phenotypic heterogeneity, with manifestations ranging from severe childhood-onset hypomyelinating leukodystrophic syndromes to milder and later-onset gait disorders with central hypomyelination, with or without additional non-neurological signs. Recently, a milder phenotype consisting of late-onset spastic ataxia without hypomyelinating leukodystrophy has been suggested to be specific to the intronic c.1909 + 22G > A mutation in POLR3A. Here, we present 10 patients from 8 unrelated families with POLR3A-related late-onset spastic ataxia, all harboring the c.1909 + 22G > A variant. Most of them showed an ataxic-spastic picture, two a "pure" cerebellar phenotype, and one a "pure" spastic presentation. The non-neurological findings typically associated with POLR3A mutations were absent in all the patients. The main findings on brain MRI were bilateral hyperintensity along the superior cerebellar peduncles on FLAIR sequences, observed in most of the patients, and cerebellar and/or spinal cord atrophy, found in half of the patients. Only one patient exhibited central hypomyelination. The POLR3A mutations present in this cohort were the c.1909 + 22G > A splice site variant found in compound heterozygosity with six additional variants (three missense, two nonsense, one splice) and, in one patient, with a novel large deletion involving exons 14-18. Interestingly, this patient had the most "complex" presentation among those observed in our cohort; it included some neurological and non-neurological features, such as seizures, neurosensory deafness, and lipomas, that have not previously been reported in association with late-onset POLR3A-related disorders, and therefore further expand the phenotype.
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Affiliation(s)
- Ilaria Di Donato
- Department of Medicine, Surgery and Neurosciences, University of Siena, viale Bracci, 16, 50055, Siena, Italy.
| | - Antonio Gallo
- Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Ivana Ricca
- Molecular Medicine and Neurogenetics, IRCCS Fondazione Stella Maris, via dei Giacinti 2, Calambrone, 56128, Pisa, Italy
| | - Nicola Fini
- Neurology Unit, Department of Neurosciences, Azienda Ospedaliero Universitaria di Modena, Modena, Italy
| | - Gabriella Silvestri
- Fondazione Policlinico Universitario 'A. Gemelli' IRCCS, UOC Neurologia, Rome, Italy
- Department of Neurosciences, Università Cattolica del Sacro Cuore, Rome, Italy
| | | | - Mario Cirillo
- Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Alfonso Cerase
- Department of Medicine, Surgery and Neurosciences, University of Siena, viale Bracci, 16, 50055, Siena, Italy
| | - Gemma Natale
- Molecular Medicine and Neurogenetics, IRCCS Fondazione Stella Maris, via dei Giacinti 2, Calambrone, 56128, Pisa, Italy
| | - Federica Matrone
- Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Vittorio Riso
- Fondazione Policlinico Universitario 'A. Gemelli' IRCCS, UOC Neurologia, Rome, Italy
- Department of Neurosciences, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Mariarosa Anna Beatrice Melone
- Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Naples, Italy
- Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, Temple University, Philadelphia, PA, USA
| | - Alessandra Tessa
- Molecular Medicine and Neurogenetics, IRCCS Fondazione Stella Maris, via dei Giacinti 2, Calambrone, 56128, Pisa, Italy
| | - Giovanna De Michele
- Department of Neurosciences, Reproductive and Odontostomatological Sciences, Federico II University, Naples, Italy
| | - Antonio Federico
- Department of Medicine, Surgery and Neurosciences, University of Siena, viale Bracci, 16, 50055, Siena, Italy
| | - Alessandro Filla
- Department of Neurosciences, Reproductive and Odontostomatological Sciences, Federico II University, Naples, Italy
| | - Maria Teresa Dotti
- Department of Medicine, Surgery and Neurosciences, University of Siena, viale Bracci, 16, 50055, Siena, Italy
| | - Filippo Maria Santorelli
- Molecular Medicine and Neurogenetics, IRCCS Fondazione Stella Maris, via dei Giacinti 2, Calambrone, 56128, Pisa, Italy.
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12
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Cogliati F, Forzano F, Russo S. Editorial: Overlapping Phenotypes and Genetic Heterogeneity of Rare Neurodevelopmental Disorders. Front Neurol 2021; 12:711288. [PMID: 34367058 PMCID: PMC8341807 DOI: 10.3389/fneur.2021.711288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 05/27/2021] [Indexed: 11/13/2022] Open
Affiliation(s)
- Francesca Cogliati
- Research Laboratory of Medical Cytogenetics and Molecular Genetics, Istituto Auxologico Italiano, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Milan, Italy
| | - Francesca Forzano
- Clinical Genetics Department, Guy's & St Thomas' National Health System Foundation Trust, London, United Kingdom
| | - Silvia Russo
- Research Laboratory of Medical Cytogenetics and Molecular Genetics, Istituto Auxologico Italiano, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Milan, Italy
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13
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Kyle K, Mason X, Bordelon Y, Pouratian N, Bronstein J. Adult onset POLR3A leukodystrophy presenting with parkinsonism treated with pallidal deep brain stimulation. Parkinsonism Relat Disord 2021; 85:23-25. [PMID: 33652360 DOI: 10.1016/j.parkreldis.2021.02.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 02/10/2021] [Accepted: 02/14/2021] [Indexed: 11/17/2022]
Affiliation(s)
- Kevin Kyle
- Department of Neurology, Massachusetts General Hospital, United States.
| | - Xenos Mason
- Department of Neurology, UCLA David Geffen School of Medicine, United States
| | - Yvette Bordelon
- Department of Neurology, UCLA David Geffen School of Medicine, United States
| | - Nader Pouratian
- Department of Neurosurgery, UCLA David Geffen School of Medicine, United States
| | - Jeff Bronstein
- Department of Neurology, UCLA David Geffen School of Medicine, United States
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14
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Furukawa S, Kunii M, Doi H, Kondo N, Ogura A, Hirabuki K, Itoh T, Matsumoto N, Tanaka F, Katsuno M, Ito Y. Case Report: Severe Osteoporosis and Preventive Therapy in RNA Polymerase III-Related Leukodystrophy. Front Neurol 2021; 12:622355. [PMID: 33716926 PMCID: PMC7952608 DOI: 10.3389/fneur.2021.622355] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/25/2021] [Indexed: 11/18/2022] Open
Abstract
RNA polymerase III (POLR3)-related leukodystrophy is an autosomal recessive form of leukodystrophy caused by homozygous or compound heterozygous mutations of the RNA polymerase III subunit genes, including subunit A (POLR3A). With respect to the manifestation triad, hypomyelination, hypodontia, and hypogonadotropic hypogonadism, it is also known as 4H leukodystrophy. Here, we report a 41-year-old woman of POLR3-related leukodystrophy by carrying compound heterozygous pathogenic variants of c.2554A>G (p.M852V) and c.2668G>T (p.V890F) in the POLR3A gene. She was amenorrheic and became a wheelchair user from the age of 15 years and suffered from multiple episodes of pathologic fractures, starting with a subtrochanteric fracture of the right femur after a tonic seizure at age 30 years. Head magnetic resonance imaging demonstrated hypomyelination and atrophies of the cerebellum, brainstem, and corpus callosum. Laboratory examination revealed a marked decrease of gonadotropins and estrogen, low bone density, and high bone resorption markers. Administration of anti-receptor activator of nuclear factor kappa-B ligand monoclonal antibody restored bone resorption markers to a normal level and prevented further pathological bone fractures. Our case emphasizes that osteoporosis should be recognized as a potential but serious complication in POLR3-related leukodystrophy. It may be feasible to prevent pathologic fractures by intensive osteoporosis therapy after endocrinological examinations and evaluation of bone metabolism.
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Affiliation(s)
- Soma Furukawa
- Department of Neurology, Toyota Memorial Hospital, Toyota, Japan.,Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Misako Kunii
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Hiroshi Doi
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Naohide Kondo
- Department of Neurology, Toyota Memorial Hospital, Toyota, Japan.,Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan.,Wellness Promotion Center, Corporate Human Resource, Fuji Xerox Co., Ltd, Ebina, Japan
| | - Aya Ogura
- Department of Neurology, Toyota Memorial Hospital, Toyota, Japan.,Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | | | - Takayuki Itoh
- Faculty of Psychological and Physical Science, Aichi-Gakuin University, Nissin, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Fumiaki Tanaka
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Masahisa Katsuno
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yasuhiro Ito
- Department of Neurology, Toyota Memorial Hospital, Toyota, Japan
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15
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Fellner A, Lossos A, Kogan E, Argov Z, Gonzaga-Jauregui C, Shuldiner AR, Darawshe M, Bazak L, Lidzbarsky G, Shomron N, Basel-Salmon L, Goldberg Y. Two intronic cis-acting variants in both alleles of the POLR3A gene cause progressive spastic ataxia with hypodontia. Clin Genet 2021; 99:713-718. [PMID: 33491183 DOI: 10.1111/cge.13929] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 01/02/2021] [Accepted: 01/19/2021] [Indexed: 12/14/2022]
Abstract
POLR3A encodes the largest subunit of the DNA-dependent RNA polymerase III. Pathogenic variants in this gene are associated with dysregulation of tRNA production and other non-coding RNAs. POLR3A-related disorders include variable phenotypes. The genotype-phenotype correlation is still unclear. Phenotypic analysis and exome sequencing were performed in four affected siblings diagnosed clinically with hereditary spastic ataxia, two healthy siblings and their unaffected mother. All four affected siblings (ages 46-55) had similar clinical features of early childhood-onset hypodontia and adolescent-onset progressive spastic ataxia. None had progeria, gonadal dysfunction or dysmorphism. All affected individuals had biallelic POLR3A pathogenic variants composed by two cis-acting intronic splicing-altering variants, c.1909 + 22G > A and c.3337-11 T > C. The two healthy siblings had wild-type alleles. The mother and another unaffected sibling were heterozygous for the allele containing both variants. This is the first report addressing the clinical consequence associated with homozygosity for a unique pathogenic intronic allele in the POLR3A gene. This allele was previously reported in compound heterozygous combinations in patients with Wiedemann-Rautenstrauch syndrome, a severe progeroid POLR3A-associated phenotype. We show that homozygosity for this allele is associated with spastic ataxia with hypodontia, and not with progeroid features. These findings contribute to the characterization of genotype-phenotype correlation in POLR3A-related disorders.
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Affiliation(s)
- Avi Fellner
- Raphael Recanati Genetics Institute, Rabin Medical Center, Beilinson Campus, Petah Tikva, Israel.,Department of Neurology, Rabin Medical Center, Beilinson Campus, Petah Tikva, Israel
| | - Alexander Lossos
- Department of Neurology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Elena Kogan
- Department of Neurology, Rabin Medical Center, Beilinson Campus, Petah Tikva, Israel
| | - Zohar Argov
- Department of Neurology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | | | | | - Malak Darawshe
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Lily Bazak
- Raphael Recanati Genetics Institute, Rabin Medical Center, Beilinson Campus, Petah Tikva, Israel
| | - Gabriel Lidzbarsky
- Raphael Recanati Genetics Institute, Rabin Medical Center, Beilinson Campus, Petah Tikva, Israel
| | - Noam Shomron
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Lina Basel-Salmon
- Raphael Recanati Genetics Institute, Rabin Medical Center, Beilinson Campus, Petah Tikva, Israel.,Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel.,Felsenstein Medical Research Center, Petah Tikva, Israel
| | - Yael Goldberg
- Raphael Recanati Genetics Institute, Rabin Medical Center, Beilinson Campus, Petah Tikva, Israel.,Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
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16
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Majethia P, Girisha KM. Wiedemann-Rautenstrauch syndrome in an Indian patient with biallelic pathogenic variants in POLR3A. Am J Med Genet A 2021; 185:1602-1605. [PMID: 33559318 DOI: 10.1002/ajmg.a.62115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 01/02/2021] [Accepted: 01/12/2021] [Indexed: 11/11/2022]
Abstract
Wiedemann-Rautenstrauch syndrome (WRS; MIM# 264090) is a rare neonatal progeroid disorder resulting from biallelic pathogenic variants in the POLR3A. It is an autosomal recessive condition characterized by growth retardation, lipoatrophy, a distinctive face, sparse scalp hair, and dental anomalies. Till date, 19 families are reported with WRS due to variants in POLR3A. Here, we describe an 18 months old male child with biallelic c.2005C>T p.(Arg669Ter) and c.1771-7C>G variant in heterozygous state identified by exome sequencing in POLR3A leading to WRS phenotype. The variant c.1771-7C>G was earlier found to be associated with hereditary spastic ataxia. We emphasize on the phenotype in an Indian patient with WRS.
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Affiliation(s)
- Purvi Majethia
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Katta Mohan Girisha
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
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17
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Uygun Ö, Gündüz T, Eraksoy M, Kürtüncü M. Adult-onset 4H leukodystrophy: a case presentation and review of the literature. Acta Neurol Belg 2020; 120:1461-2. [PMID: 32052360 DOI: 10.1007/s13760-020-01297-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 01/30/2020] [Indexed: 10/25/2022]
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18
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Zhang X, Xiang Y, He D, Liang B, Wang C, Luo J, Zheng F. Identification of Potential Biomarkers for CAD Using Integrated Expression and Methylation Data. Front Genet 2020; 11:778. [PMID: 33033488 PMCID: PMC7509170 DOI: 10.3389/fgene.2020.00778] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 06/30/2020] [Indexed: 11/25/2022] Open
Abstract
DNA methylation plays an essential role in the pathogenesis of coronary artery disease (CAD) through regulating mRNA expressions. This study aimed to identify hub genes regulated by DNA methylation as biomarkers of CAD. Gene expression and methylation datasets of peripheral blood leukocytes (PBLs) of CAD were downloaded from the Gene Expression Omnibus (GEO) database. Subsequently, multiple computational approaches were performed to analyze the regulatory networks and to recognize hub genes. Finally, top hub genes were verified in a case-control study, based on their differential expressions and methylation levels between CAD cases and controls. In total, 535 differentially expressed-methylated genes (DEMGs) were identified and partitioned into 4 subgroups. TSS200 and 5′UTR were confirmed as high enrichment areas of differentially methylated CpGs sites (DMCs). The function of DEMGs is enriched in processes of histone H3-K27 methylation, regulation of post-transcription and DNA-directed RNA polymerase activity. Pathway enrichment showed DEMGs participated in the VEGF signaling pathway, adipocytokine signaling pathway, and PI3K-Akt signaling pathway. Besides, expressions of hub genes fibronectin 1 (FN1), phosphatase (PTEN), and tensin homolog and RNA polymerase III subunit A (POLR3A) were discordantly expressed between CAD patients and controls and related with DNA methylation levels. In conclusion, our study identified the potential biomarkers of PBLs for CAD, in which FN1, PTEN, and POLR3A were confirmed.
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Affiliation(s)
- Xiaokang Zhang
- Department of Clinical Laboratory Medicine and Center for Gene Diagnosis, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yang Xiang
- Department of Clinical Laboratory Medicine and Center for Gene Diagnosis, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Dingdong He
- Department of Clinical Laboratory Medicine and Center for Gene Diagnosis, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Bin Liang
- Department of Clinical Laboratory Medicine and Center for Gene Diagnosis, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Chen Wang
- Department of Clinical Laboratory Medicine and Center for Gene Diagnosis, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Jing Luo
- Department of Clinical Laboratory Medicine and Center for Gene Diagnosis, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Fang Zheng
- Department of Clinical Laboratory Medicine and Center for Gene Diagnosis, Zhongnan Hospital of Wuhan University, Wuhan, China
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19
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Hiraide T, Kubota K, Kono Y, Watanabe S, Matsubayashi T, Nakashima M, Kaname T, Fukao T, Shimozawa N, Ogata T, Saitsu H. POLR3A variants in striatal involvement without diffuse hypomyelination. Brain Dev 2020; 42:363-368. [PMID: 31932101 DOI: 10.1016/j.braindev.2019.12.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 12/26/2019] [Accepted: 12/27/2019] [Indexed: 11/27/2022]
Abstract
BACKGROUND Biallelic variants in POLR3A encoding the largest subunit of RNA polymerase III cause POLR3-related (or 4H) leukodystrophy characterized by neurologic dysfunction, abnormal dentition, endocrine abnormalities and ocular abnormality. Recently, whole-exome sequencing enabled the discovery of POLR3A variants in cases lacking diffuse hypomyelination, the principal MRI phenotype of POLR3-related leukodystrophy. Homozygous c.1771-6C > G variants in POLR3A were recently suggested to cause striatal and red nucleus involvement without white matter involvement. CASE REPORT Here, we report three cases in two families with biallelic POLR3A variants. We identified two sets of compound heterozygous variants in POLR3A, c.1771-6C > G and c.791C > T, p.(Pro264Leu) for family 1 and c.1771-6C > G and c.2671C > T, p.(Arg891*) for family 2. Both families had the c.1771-6C > G variant, which led to aberrant mRNA splicing. Neuropsychiatric regression and severe intellectual disability were identified in three patients. Two cases showed dystonia and oligodontia. Notably, characteristic bilateral symmetric atrophy and abnormal signal of the striatum without diffuse white matter signal change were observed in brain MRI of all three individuals. CONCLUSIONS Striatum abnormalities may be another distinctive MRI finding associated with POLR3A variants, especially in cases including c.1771-6C > G variants and our cases can expand the phenotypic spectrum of POLR3A-related disorders.
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Affiliation(s)
- Takuya Hiraide
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan; Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Kazuo Kubota
- Department of Pediatrics, Gifu University Graduate School of Medicine, Gifu, Japan; Division of Clinical Genetics, Gifu University Hospital, Japan
| | - Yu Kono
- Department of Neurology, Fuji City General Hospital, Shizuoka, Japan
| | - Seiji Watanabe
- Department of Pediatric Neurology, Shizuoka Children's Hospital, Shizuoka, Japan
| | - Tomoko Matsubayashi
- Department of Pediatric Neurology, Shizuoka Children's Hospital, Shizuoka, Japan
| | - Mitsuko Nakashima
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Tadashi Kaname
- Department of Genome Medicine, National Center for Child Health and Development, Tokyo, Japan
| | - Toshiyuki Fukao
- Department of Pediatrics, Gifu University Graduate School of Medicine, Gifu, Japan; Division of Clinical Genetics, Gifu University Hospital, Japan
| | - Nobuyuki Shimozawa
- Division of Clinical Genetics, Gifu University Hospital, Japan; Division of Genomics Research, Life Science Research Center, Gifu University, Gifu, Japan
| | - Tsutomu Ogata
- Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan.
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20
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Harting I, Al-Saady M, Krägeloh-Mann I, Bley A, Hempel M, Bierhals T, Karch S, Moog U, Bernard G, Huntsman R, van Spaendonk RML, Vreeburg M, Rodríguez-Palmero A, Pujol A, van der Knaap MS, Pouwels PJW, Wolf NI. POLR3A variants with striatal involvement and extrapyramidal movement disorder. Neurogenetics 2020; 21:121-33. [PMID: 31940116 DOI: 10.1007/s10048-019-00602-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 12/27/2019] [Indexed: 01/10/2023]
Abstract
Biallelic variants in POLR3A cause 4H leukodystrophy, characterized by hypomyelination in combination with cerebellar and pyramidal signs and variable non-neurological manifestations. Basal ganglia are spared in 4H leukodystrophy, and dystonia is not prominent. Three patients with variants in POLR3A, an atypical presentation with dystonia, and MR involvement of putamen and caudate nucleus (striatum) and red nucleus have previously been reported. Genetic, clinical findings and 18 MRI scans from nine patients with homozygous or compound heterozygous POLR3A variants and predominant striatal changes were retrospectively reviewed in order to characterize the striatal variant of POLR3A-associated disease. Prominent extrapyramidal involvement was the predominant clinical sign in all patients. The three youngest children were severely affected with muscle hypotonia, impaired head control, and choreic movements. Presentation of the six older patients was milder. Two brothers diagnosed with juvenile parkinsonism were homozygous for the c.1771-6C > G variant in POLR3A; the other seven either carried c.1771-6C > G (n = 1) or c.1771-7C > G (n = 7) together with another variant (missense, synonymous, or intronic). Striatal T2-hyperintensity and atrophy together with involvement of the superior cerebellar peduncles were characteristic. Additional MRI findings were involvement of dentate nuclei, hila, or peridentate white matter (3, 6, and 4/9), inferior cerebellar peduncles (6/9), red nuclei (2/9), and abnormal myelination of pyramidal and visual tracts (6/9) but no frank hypomyelination. Clinical and MRI findings in patients with a striatal variant of POLR3A-related disease are distinct from 4H leukodystrophy and associated with one of two intronic variants, c.1771-6C > G or c.1771-7C > G, in combination with another POLR3A variant.
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21
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Abstract
Pol III-related leukodystrophy is a recently recognized category of leukodystrophy with characteristic clinical presentation and imaging findings. These cases are diagnosed by the combination of typical clinical presentation, brain magnetic resonance imaging findings, and the presence of biallelic pathogenic mutations in three specific genes. We present the case of a 6-year-old girl who demonstrated the classic clinical and imaging features of this disorder. This case report aims to raise awareness of this disorder so that it is easily recognized in the appropriate setting.
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Affiliation(s)
- Aby Thomas
- Corresponding author: Aby Thomas, Department of Radiology, University of Tennessee Health Science Center, LeBonheur Children’s Hospital, Memphis, Tennessee 38103, USA.
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22
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Choquet K, Pinard M, Yang S, Moir RD, Poitras C, Dicaire MJ, Sgarioto N, Larivière R, Kleinman CL, Willis IM, Gauthier MS, Coulombe B, Brais B. The leukodystrophy mutation Polr3b R103H causes homozygote mouse embryonic lethality and impairs RNA polymerase III biogenesis. Mol Brain 2019; 12:59. [PMID: 31221184 PMCID: PMC6587292 DOI: 10.1186/s13041-019-0479-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 06/11/2019] [Indexed: 01/16/2023] Open
Abstract
Recessive mutations in the ubiquitously expressed POLR3A and POLR3B genes are the most common cause of POLR3-related hypomyelinating leukodystrophy (POLR3-HLD), a rare childhood-onset disorder characterized by deficient cerebral myelin formation and cerebellar atrophy. POLR3A and POLR3B encode the two catalytic subunits of RNA Polymerase III (Pol III), which synthesizes numerous small non-coding RNAs. We recently reported that mice homozygous for the Polr3a mutation c.2015G > A (p.Gly672Glu) have no neurological abnormalities and thus do not recapitulate the human POLR3-HLD phenotype. To determine if other POLR3-HLD mutations can cause a leukodystrophy phenotype in mouse, we characterized mice carrying the Polr3b mutation c.308G > A (p.Arg103His). Surprisingly, homozygosity for this mutation was embryonically lethal with only wild-type and heterozygous animals detected at embryonic day 9.5. Using proteomics in a human cell line, we found that the POLR3B R103H mutation severely impairs assembly of the Pol III complex. We next generated Polr3aG672E/G672E/Polr3b+/R103Hdouble mutant mice but observed that this additional mutation was insufficient to elicit a neurological or transcriptional phenotype. Taken together with our previous study on Polr3a G672E mice, our results indicate that missense mutations in Polr3a and Polr3b can variably impair mouse development and Pol III function. Developing a proper model of POLR3-HLD is crucial to gain insights into the pathophysiological mechanisms involved in this devastating neurodegenerative disease.
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Affiliation(s)
- Karine Choquet
- Montreal Neurological Institute, McGill University, 3801 University Street, room 622, Montréal, Québec, H3A 2B4, Canada.,Department of Human Genetics, McGill University, Québec, Montréal, Canada.,Lady Davis Institute for Medical Research, Jewish General Hospital, Québec, Montréal, Canada
| | - Maxime Pinard
- Translational Proteomics Laboratory, Institut de recherches cliniques de Montréal (IRCM), Québec, Montréal, Canada
| | - Sharon Yang
- Montreal Neurological Institute, McGill University, 3801 University Street, room 622, Montréal, Québec, H3A 2B4, Canada
| | - Robyn D Moir
- Department of Biochemistry, Albert Einstein College of Medicine, New York, Bronx, USA
| | - Christian Poitras
- Translational Proteomics Laboratory, Institut de recherches cliniques de Montréal (IRCM), Québec, Montréal, Canada
| | - Marie-Josée Dicaire
- Montreal Neurological Institute, McGill University, 3801 University Street, room 622, Montréal, Québec, H3A 2B4, Canada
| | - Nicolas Sgarioto
- Montreal Neurological Institute, McGill University, 3801 University Street, room 622, Montréal, Québec, H3A 2B4, Canada
| | - Roxanne Larivière
- Montreal Neurological Institute, McGill University, 3801 University Street, room 622, Montréal, Québec, H3A 2B4, Canada
| | - Claudia L Kleinman
- Department of Human Genetics, McGill University, Québec, Montréal, Canada.,Lady Davis Institute for Medical Research, Jewish General Hospital, Québec, Montréal, Canada
| | - Ian M Willis
- Department of Biochemistry, Albert Einstein College of Medicine, New York, Bronx, USA
| | - Marie-Soleil Gauthier
- Translational Proteomics Laboratory, Institut de recherches cliniques de Montréal (IRCM), Québec, Montréal, Canada
| | - Benoit Coulombe
- Translational Proteomics Laboratory, Institut de recherches cliniques de Montréal (IRCM), Québec, Montréal, Canada.,Département de biochimie et médecine moléculaire, Université de Montréal, Québec, Montréal, Canada
| | - Bernard Brais
- Montreal Neurological Institute, McGill University, 3801 University Street, room 622, Montréal, Québec, H3A 2B4, Canada. .,Department of Human Genetics, McGill University, Québec, Montréal, Canada.
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23
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Lessel D, Ozel AB, Campbell SE, Saadi A, Arlt MF, McSweeney KM, Plaiasu V, Szakszon K, Szőllős A, Rusu C, Rojas AJ, Lopez-Valdez J, Thiele H, Nürnberg P, Nickerson DA, Bamshad MJ, Li JZ, Kubisch C, Glover TW, Gordon LB. Analyses of LMNA-negative juvenile progeroid cases confirms biallelic POLR3A mutations in Wiedemann-Rautenstrauch-like syndrome and expands the phenotypic spectrum of PYCR1 mutations. Hum Genet 2018; 137:921-939. [PMID: 30450527 PMCID: PMC6652186 DOI: 10.1007/s00439-018-1957-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 11/02/2018] [Indexed: 02/07/2023]
Abstract
Juvenile segmental progeroid syndromes are rare, heterogeneous disorders characterized by signs of premature aging affecting more than one tissue or organ starting in childhood. Hutchinson-Gilford progeria syndrome (HGPS), caused by a recurrent de novo synonymous LMNA mutation resulting in aberrant splicing and generation of a mutant product called progerin, is a prototypical example of such disorders. Here, we performed a joint collaborative study using massively parallel sequencing and targeted Sanger sequencing, aimed at delineating the underlying genetic cause of 14 previously undiagnosed, clinically heterogeneous, non-LMNA-associated juvenile progeroid patients. The molecular diagnosis was achieved in 11 of 14 cases (~ 79%). Furthermore, we firmly establish biallelic mutations in POLR3A as the genetic cause of a recognizable, neonatal, Wiedemann-Rautenstrauch-like progeroid syndrome. Thus, we suggest that POLR3A mutations are causal for a portion of under-diagnosed early-onset segmental progeroid syndromes. We additionally expand the clinical spectrum associated with PYCR1 mutations by showing that they can somewhat resemble HGPS in the first year of life. Moreover, our results lead to clinical reclassification in one single case. Our data emphasize the complex genetic and clinical heterogeneity underlying progeroid disorders.
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Affiliation(s)
- Davor Lessel
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
| | - Ayse Bilge Ozel
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Susan E Campbell
- Center for Gerontology and Healthcare Research, Brown University, Providence, RI, USA
| | - Abdelkrim Saadi
- Service de neurologie, CHU Ben Aknoun Alger, 2 route des deux Bassins, BenAknoun,, Algers, Algeria
| | - Martin F Arlt
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Keisha Melodi McSweeney
- Oak Ridge Institute for Science and Education, Office of Biotechnology Products, Center for Drug Evaluation and Research, Food and Drug Administration, 20993, Silver Spring, MD, USA
| | - Vasilica Plaiasu
- Regional Center of Medical Genetics, Alessandrescu-Rusescu INSMC, Bucharest, Romania
| | - Katalin Szakszon
- Department of Pediatrics, University of Debrecen, Debrecen, Hungary
| | - Anna Szőllős
- Department of Pediatrics, University of Debrecen, Debrecen, Hungary
| | - Cristina Rusu
- Department of Genetics, University Hospital Iasi, Iasi, Romania
| | - Armando J Rojas
- Instituto de Genética Humana, Facultad de Medicina, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Jaime Lopez-Valdez
- Department of Genetics, Centenario Hospital Miguel Hidalgo, Aguascalientes, Mexico
| | - Holger Thiele
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Peter Nürnberg
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | | | - Michael J Bamshad
- Department of Genome Sciences, University of Washington, Seattle, USA
| | - Jun Z Li
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Christian Kubisch
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Thomas W Glover
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Leslie B Gordon
- Warren Alpert Medical School of Brown University, Providence, RI, USA
- Department of Pediatrics, Division of Genetics, Hasbro Children's Hospital, Providence, RI, USA
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24
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Paolacci S, Li Y, Agolini E, Bellacchio E, Arboleda-Bustos CE, Carrero D, Bertola D, Al-Gazali L, Alders M, Altmüller J, Arboleda G, Beleggia F, Bruselles A, Ciolfi A, Gillessen-Kaesbach G, Krieg T, Mohammed S, Müller C, Novelli A, Ortega J, Sandoval A, Velasco G, Yigit G, Arboleda H, Lopez-Otin C, Wollnik B, Tartaglia M, Hennekam RC. Specific combinations of biallelic POLR3A variants cause Wiedemann-Rautenstrauch syndrome. J Med Genet 2018; 55:837-846. [PMID: 30323018 DOI: 10.1136/jmedgenet-2018-105528] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 08/28/2018] [Accepted: 09/09/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND Wiedemann-Rautenstrauch syndrome (WRS) is a form of segmental progeria presenting neonatally, characterised by growth retardation, sparse scalp hair, generalised lipodystrophy with characteristic local fatty tissue accumulations and unusual face. We aimed to understand its molecular cause. METHODS We performed exome sequencing in two families, targeted sequencing in 10 other families and performed in silico modelling studies and transcript processing analyses to explore the structural and functional consequences of the identified variants. RESULTS Biallelic POLR3A variants were identified in eight affected individuals and monoallelic variants of the same gene in four other individuals. In the latter, lack of genetic material precluded further analyses. Multiple variants were found to affect POLR3A transcript processing and were mostly located in deep intronic regions, making clinical suspicion fundamental to detection. While biallelic POLR3A variants have been previously reported in 4H syndrome and adolescent-onset progressive spastic ataxia, recurrent haplotypes specifically occurring in individuals with WRS were detected. All WRS-associated POLR3A amino acid changes were predicted to perturb substantially POLR3A structure/function. CONCLUSION Biallelic mutations in POLR3A, which encodes for the largest subunit of the DNA-dependent RNA polymerase III, underlie WRS. No isolated functional sites in POLR3A explain the phenotype variability in POLR3A-related disorders. We suggest that specific combinations of compound heterozygous variants must be present to cause the WRS phenotype. Our findings expand the molecular mechanisms contributing to progeroid disorders.
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Affiliation(s)
- Stefano Paolacci
- Department of Experimental Medicine, Sapienza "University of Rome", Rome, Italy
| | - Yun Li
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Emanuele Agolini
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, Roma, Italy
| | - Emanuele Bellacchio
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, Roma, Italy
| | - Carlos E Arboleda-Bustos
- Neuroscience and Cell Death Group, Faculty of Medicine and Institute of Genetics, Universidad Nacional de Colombia, Bogota, Colombia
| | - Dido Carrero
- Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Oncología (IUOPA), Universidad de Oviedo, and Centro de Investigación Biomédica en Red de Cáncer, Oviedo, Spain
| | - Debora Bertola
- Unidade de Genética do Instituto da Criança, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, e Centro de Estudos sobre o Genoma Humano e Células-Tronco do Instituto de Biociências da Universidade de São Paulo, São Paulo, Brazil
| | - Lihadh Al-Gazali
- Department of Paediatric, College of Medicine and Health Science, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Mariel Alders
- Department of Clinical Genetics, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Janine Altmüller
- Cologne Centre for Genomics and Centre for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Gonzalo Arboleda
- Neuroscience and Cell Death Group, Faculty of Medicine and Institute of Genetics, Universidad Nacional de Colombia, Bogota, Colombia
| | - Filippo Beleggia
- Department of Internal Medicine I, University Hospital Cologne, Cologne, Germany
| | - Alessandro Bruselles
- Dipartimento di Oncologia e Medicina Molecolare, Istituto Superiore di Sanità, Rome, Italy
| | - Andrea Ciolfi
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, Roma, Italy
| | | | - Thomas Krieg
- Department of Dermatology, University Hospital Cologne, Cologne, Germany
| | | | - Christian Müller
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Antonio Novelli
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, Roma, Italy
| | - Jenny Ortega
- Neuroscience and Cell Death Group, Faculty of Medicine and Institute of Genetics, Universidad Nacional de Colombia, Bogota, Colombia
| | - Adrian Sandoval
- Neuroscience and Cell Death Group, Faculty of Medicine and Institute of Genetics, Universidad Nacional de Colombia, Bogota, Colombia
| | - Gloria Velasco
- Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Oncología (IUOPA), Universidad de Oviedo, and Centro de Investigación Biomédica en Red de Cáncer, Oviedo, Spain
| | - Gökhan Yigit
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Humberto Arboleda
- Neuroscience and Cell Death Group, Faculty of Medicine and Institute of Genetics, Universidad Nacional de Colombia, Bogota, Colombia
| | - Carlos Lopez-Otin
- Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Oncología (IUOPA), Universidad de Oviedo, and Centro de Investigación Biomédica en Red de Cáncer, Oviedo, Spain
| | - Bernd Wollnik
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, Roma, Italy
| | - Raoul C Hennekam
- Department of Paediatrics, Amsterdam UMC - location AMC, University of Amsterdam, Amsterdam, The Netherlands
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25
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Minnerop M, Kurzwelly D, Wagner H, Soehn AS, Reichbauer J, Tao F, Rattay TW, Peitz M, Rehbach K, Giorgetti A, Pyle A, Thiele H, Altmüller J, Timmann D, Karaca I, Lennarz M, Baets J, Hengel H, Synofzik M, Atasu B, Feely S, Kennerson M, Stendel C, Lindig T, Gonzalez MA, Stirnberg R, Sturm M, Roeske S, Jung J, Bauer P, Lohmann E, Herms S, Heilmann-Heimbach S, Nicholson G, Mahanjah M, Sharkia R, Carloni P, Brüstle O, Klopstock T, Mathews KD, Shy ME, de Jonghe P, Chinnery PF, Horvath R, Kohlhase J, Schmitt I, Wolf M, Greschus S, Amunts K, Maier W, Schöls L, Nürnberg P, Zuchner S, Klockgether T, Ramirez A, Schüle R. Hypomorphic mutations in POLR3A are a frequent cause of sporadic and recessive spastic ataxia. Brain 2017; 140:1561-1578. [PMID: 28459997 PMCID: PMC6402316 DOI: 10.1093/brain/awx095] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 02/08/2017] [Accepted: 02/26/2017] [Indexed: 11/12/2022] Open
Abstract
Despite extensive efforts, half of patients with rare movement disorders such as hereditary spastic paraplegias and cerebellar ataxias remain genetically unexplained, implicating novel genes and unrecognized mutations in known genes. Non-coding DNA variants are suspected to account for a substantial part of undiscovered causes of rare diseases. Here we identified mutations located deep in introns of POLR3A to be a frequent cause of hereditary spastic paraplegia and cerebellar ataxia. First, whole-exome sequencing findings in a recessive spastic ataxia family turned our attention to intronic variants in POLR3A, a gene previously associated with hypomyelinating leukodystrophy type 7. Next, we screened a cohort of hereditary spastic paraplegia and cerebellar ataxia cases (n = 618) for mutations in POLR3A and identified compound heterozygous POLR3A mutations in ∼3.1% of index cases. Interestingly, >80% of POLR3A mutation carriers presented the same deep-intronic mutation (c.1909+22G>A), which activates a cryptic splice site in a tissue and stage of development-specific manner and leads to a novel distinct and uniform phenotype. The phenotype is characterized by adolescent-onset progressive spastic ataxia with frequent occurrence of tremor, involvement of the central sensory tracts and dental problems (hypodontia, early onset of severe and aggressive periodontal disease). Instead of the typical hypomyelination magnetic resonance imaging pattern associated with classical POLR3A mutations, cases carrying c.1909+22G>A demonstrated hyperintensities along the superior cerebellar peduncles. These hyperintensities may represent the structural correlate to the cerebellar symptoms observed in these patients. The associated c.1909+22G>A variant was significantly enriched in 1139 cases with spastic ataxia-related phenotypes as compared to unrelated neurological and non-neurological phenotypes and healthy controls (P = 1.3 × 10-4). In this study we demonstrate that (i) autosomal-recessive mutations in POLR3A are a frequent cause of hereditary spastic ataxias, accounting for about 3% of hitherto genetically unclassified autosomal recessive and sporadic cases; and (ii) hypomyelination is frequently absent in POLR3A-related syndromes, especially when intronic mutations are present, and thus can no longer be considered as the unifying feature of POLR3A disease. Furthermore, our results demonstrate that substantial progress in revealing the causes of Mendelian diseases can be made by exploring the non-coding sequences of the human genome.
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Affiliation(s)
- Martina Minnerop
- Institute of Neuroscience and Medicine (INM-1), Research Centre Juelich,
52425 Jülich, Germany
- Department of Neurology, University of Bonn, 53127 Bonn, Germany
| | - Delia Kurzwelly
- Department of Neurology, University of Bonn, 53127 Bonn, Germany
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn,
Germany
| | - Holger Wagner
- Department of Psychiatry and Psychotherapy, University of Bonn, 53127
Bonn, Germany
| | - Anne S Soehn
- Institute of Medical Genetics and Applied Genomics, University of
Tübingen, 72076 Tübingen, Germany
| | - Jennifer Reichbauer
- Center for Neurology and Hertie Institute for Clinical Brain Research,
University of Tübingen, 72076 Tübingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen,
Germany
| | - Feifei Tao
- Dr. John T. Macdonald Foundation Department of Human Genetics and John
P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine,
Miami, Florida 33136, USA
| | - Tim W Rattay
- Center for Neurology and Hertie Institute for Clinical Brain Research,
University of Tübingen, 72076 Tübingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen,
Germany
| | - Michael Peitz
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn,
Germany
- Institute of Reconstructive Neurobiology, Life and Brain Center, 53127
Bonn, Germany
| | - Kristina Rehbach
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn,
Germany
- Institute of Reconstructive Neurobiology, Life and Brain Center, 53127
Bonn, Germany
| | - Alejandro Giorgetti
- Computational Biophysics, German Research School for Simulation
Sciences, and Computational Biomedicine, Institute for Advanced Simulation (IAS-5) and
Institute of Neuroscience and Medicine (INM-9), Research Centre Juelich, 52425 Jülich,
Germany
- Department of Biotechnology, University of Verona, 37134 Verona,
Italy
| | - Angela Pyle
- Institute of Genetic Medicine, Newcastle University, Newcastle upon
Tyne NE1 3BZ, UK
| | - Holger Thiele
- Cologne Center for Genomics (CCG), University of Cologne, 50931
Cologne, Germany
| | - Janine Altmüller
- Cologne Center for Genomics (CCG), University of Cologne, 50931
Cologne, Germany
- Institute of Human Genetics, University Hospital of Cologne, 50931
Cologne, Germany
| | - Dagmar Timmann
- Department of Neurology, University of Duisburg-Essen, 45147 Essen,
Germany
| | - Ilker Karaca
- Department of Psychiatry and Psychotherapy, University of Bonn, 53127
Bonn, Germany
| | - Martina Lennarz
- Department of Psychiatry and Psychotherapy, University of Bonn, 53127
Bonn, Germany
| | - Jonathan Baets
- Neurogenetics Group, VIB-Department of Molecular Genetics, VIB, 2610
Antwerp, Belgium
- Department of Neurology, Antwerp University Hospital, 2650 Antwerp,
Belgium
- Institute Born-Bunge, University of Antwerp, 2610 Antwerp,
Belgium
| | - Holger Hengel
- Center for Neurology and Hertie Institute for Clinical Brain Research,
University of Tübingen, 72076 Tübingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen,
Germany
| | - Matthis Synofzik
- Center for Neurology and Hertie Institute for Clinical Brain Research,
University of Tübingen, 72076 Tübingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen,
Germany
| | - Burcu Atasu
- German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen,
Germany
- Department of Neurodegenerative Diseases, Hertie Institute for Clinical
Brain Research, University of Tübingen, 72076 Tübingen, Germany
| | - Shawna Feely
- Department of Neurology, University of Iowa, 52242 Iowa, USA
| | - Marina Kennerson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord
NSW 2139, Australia
- Molecular Medicine Laboratory, Concord Hospital, Concord NSW 2139,
Australia
- Sydney Medical School, University of Sydney, Sydney NSW 2006,
Australia
| | - Claudia Stendel
- Department of Neurology, Friedrich-Baur-Institute,
Ludwig-Maximilians-Universität, 80336 Munich, Germany
- German Center for Neurodegenerative Diseases (DZNE), 81337 Munich,
Germany
| | - Tobias Lindig
- Department of Diagnostic and Interventional Neuroradiology, University
Hospital Tübingen, 72076 Tübingen, Germany
| | - Michael A Gonzalez
- Dr. John T. Macdonald Foundation Department of Human Genetics and John
P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine,
Miami, Florida 33136, USA
| | - Rüdiger Stirnberg
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn,
Germany
| | - Marc Sturm
- Institute of Medical Genetics and Applied Genomics, University of
Tübingen, 72076 Tübingen, Germany
| | - Sandra Roeske
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn,
Germany
| | - Johanna Jung
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn,
Germany
| | - Peter Bauer
- Institute of Medical Genetics and Applied Genomics, University of
Tübingen, 72076 Tübingen, Germany
| | - Ebba Lohmann
- German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen,
Germany
- Department of Neurology, Antwerp University Hospital, 2650 Antwerp,
Belgium
- Behavioural Neurology and Movement Disorders Unit, Department of
Neurology, Istanbul Faculty of Medicine, Istanbul University, 34093 Istanbul, Turkey
| | - Stefan Herms
- Institute of Human Genetics, University of Bonn, 53127 Bonn,
Germany
- Department of Genomics, Life and Brain Center, University of Bonn,
53127, Bonn, Germany
- Division of Medical Genetics, University Hospital and Department of
Biomedicine, University of Basel, CH-4058, Basel, Switzerland
| | - Stefanie Heilmann-Heimbach
- Institute of Human Genetics, University of Bonn, 53127 Bonn,
Germany
- Department of Genomics, Life and Brain Center, University of Bonn,
53127, Bonn, Germany
| | - Garth Nicholson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord
NSW 2139, Australia
- Molecular Medicine Laboratory, Concord Hospital, Concord NSW 2139,
Australia
- Sydney Medical School, University of Sydney, Sydney NSW 2006,
Australia
| | - Muhammad Mahanjah
- Child Neurology and Development Center, Hillel-Yaffe Medical Center,
38100 Hadera, Israel
- Bruce and Ruth Rappaport Faculty of Medicine, Technion, 31096 Haifa,
Israel
| | - Rajech Sharkia
- The Triangle Regional Research and Development Center, P. O. Box-2167,
Kfar Qari’ 30075, Israel
- Beit-Berl Academic College, Beit-Berl 44905, Israel
| | - Paolo Carloni
- Computational Biophysics, German Research School for Simulation
Sciences, and Computational Biomedicine, Institute for Advanced Simulation (IAS-5) and
Institute of Neuroscience and Medicine (INM-9), Research Centre Juelich, 52425 Jülich,
Germany
| | - Oliver Brüstle
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn,
Germany
- Institute of Reconstructive Neurobiology, Life and Brain Center, 53127
Bonn, Germany
| | - Thomas Klopstock
- Department of Neurology, Friedrich-Baur-Institute,
Ludwig-Maximilians-Universität, 80336 Munich, Germany
- German Center for Neurodegenerative Diseases (DZNE), 81337 Munich,
Germany
- Munich Cluster of Systems Neurology (SyNergy), 80336 Munich,
Germany
| | - Katherine D Mathews
- Department of Pediatrics, Carver College of Medicine, University of
Iowa, 52242 Iowa, USA
| | - Michael E Shy
- Department of Neurology, University of Iowa, 52242 Iowa, USA
| | - Peter de Jonghe
- Neurogenetics Group, VIB-Department of Molecular Genetics, VIB, 2610
Antwerp, Belgium
- Department of Neurology, Antwerp University Hospital, 2650 Antwerp,
Belgium
- Institute Born-Bunge, University of Antwerp, 2610 Antwerp,
Belgium
| | - Patrick F Chinnery
- Institute of Genetic Medicine, Newcastle University, Newcastle upon
Tyne NE1 3BZ, UK
- Department of Clinical Neurosciences, Cambridge Biomedical Campus,
University of Cambridge, Cambridge CB2 0QQ, UK
| | - Rita Horvath
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic
Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | | | - Ina Schmitt
- Department of Neurology, University of Bonn, 53127 Bonn, Germany
| | - Michael Wolf
- Departement of Orthodontics, University of Bonn, 53111 Bonn,
Germany
| | - Susanne Greschus
- Department of Radiology, University of Bonn, 53127 Bonn, Germany
| | - Katrin Amunts
- Institute of Neuroscience and Medicine (INM-1), Research Centre Juelich,
52425 Jülich, Germany
- C. & O. Vogt-Institute of Brain Research, University of Düsseldorf,
40212 Düsseldorf, Germany
| | - Wolfgang Maier
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn,
Germany
- Department of Psychiatry and Psychotherapy, University of Bonn, 53127
Bonn, Germany
| | - Ludger Schöls
- Center for Neurology and Hertie Institute for Clinical Brain Research,
University of Tübingen, 72076 Tübingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen,
Germany
| | - Peter Nürnberg
- Institute of Neuroscience and Medicine (INM-1), Research Centre Juelich,
52425 Jülich, Germany
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn,
Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne,
50931 Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in
Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Stephan Zuchner
- Dr. John T. Macdonald Foundation Department of Human Genetics and John
P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine,
Miami, Florida 33136, USA
| | - Thomas Klockgether
- Department of Neurology, University of Bonn, 53127 Bonn, Germany
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn,
Germany
| | - Alfredo Ramirez
- Department of Psychiatry and Psychotherapy, University of Bonn, 53127
Bonn, Germany
- Institute of Human Genetics, University of Bonn, 53127 Bonn,
Germany
- Department of Psychiatry and Psychotherapy, University of Cologne,
50937 Cologne, Germany
| | - Rebecca Schüle
- Center for Neurology and Hertie Institute for Clinical Brain Research,
University of Tübingen, 72076 Tübingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen,
Germany
- Dr. John T. Macdonald Foundation Department of Human Genetics and John
P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine,
Miami, Florida 33136, USA
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26
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Choquet K, Yang S, Moir RD, Forget D, Larivière R, Bouchard A, Poitras C, Sgarioto N, Dicaire MJ, Noohi F, Kennedy TE, Rochford J, Bernard G, Teichmann M, Coulombe B, Willis IM, Kleinman CL, Brais B. Absence of neurological abnormalities in mice homozygous for the Polr3a G672E hypomyelinating leukodystrophy mutation. Mol Brain 2017; 10:13. [PMID: 28407788 PMCID: PMC5391615 DOI: 10.1186/s13041-017-0294-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 04/04/2017] [Indexed: 01/08/2023] Open
Abstract
Recessive mutations in the ubiquitously expressed POLR3A gene cause one of the most frequent forms of childhood-onset hypomyelinating leukodystrophy (HLD): POLR3-HLD. POLR3A encodes the largest subunit of RNA Polymerase III (Pol III), which is responsible for the transcription of transfer RNAs (tRNAs) and a large array of other small non-coding RNAs. In order to study the central nervous system pathophysiology of the disease, we introduced the French Canadian founder Polr3a mutation c.2015G > A (p.G672E) in mice, generating homozygous knock-in (KI/KI) as well as compound heterozygous mice for one Polr3a KI and one null allele (KI/KO). Both KI/KI and KI/KO mice are viable and are able to reproduce. To establish if they manifest a motor phenotype, WT, KI/KI and KI/KO mice were submitted to a battery of behavioral tests over one year. The KI/KI and KI/KO mice have overall normal balance, muscle strength and general locomotion. Cerebral and cerebellar Luxol Fast Blue staining and measurement of levels of myelin proteins showed no significant differences between the three groups, suggesting that myelination is not overtly impaired in Polr3a KI/KI and KI/KO mice. Finally, expression levels of several Pol III transcripts in the brain showed no statistically significant differences. We conclude that the first transgenic mice with a leukodystrophy-causing Polr3a mutation do not recapitulate the childhood-onset HLD observed in the majority of human patients with POLR3A mutations, and provide essential information to guide selection of Polr3a mutations for developing future mouse models of the disease.
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Affiliation(s)
- Karine Choquet
- Montreal Neurological Institute, McGill University, 3801 University Street, room 622, Montréal, Québec, H3A 2B4, Canada.,Department of Human Genetics, McGill University, Montréal, Québec, Canada.,Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada
| | - Sharon Yang
- Montreal Neurological Institute, McGill University, 3801 University Street, room 622, Montréal, Québec, H3A 2B4, Canada
| | - Robyn D Moir
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Diane Forget
- Translational Proteomics Laboratory, Institut de recherches cliniques de Montréal (IRCM), Montréal, Québec, Canada
| | - Roxanne Larivière
- Montreal Neurological Institute, McGill University, 3801 University Street, room 622, Montréal, Québec, H3A 2B4, Canada
| | - Annie Bouchard
- Translational Proteomics Laboratory, Institut de recherches cliniques de Montréal (IRCM), Montréal, Québec, Canada
| | - Christian Poitras
- Translational Proteomics Laboratory, Institut de recherches cliniques de Montréal (IRCM), Montréal, Québec, Canada
| | - Nicolas Sgarioto
- Montreal Neurological Institute, McGill University, 3801 University Street, room 622, Montréal, Québec, H3A 2B4, Canada
| | - Marie-Josée Dicaire
- Montreal Neurological Institute, McGill University, 3801 University Street, room 622, Montréal, Québec, H3A 2B4, Canada
| | - Forough Noohi
- Montreal Neurological Institute, McGill University, 3801 University Street, room 622, Montréal, Québec, H3A 2B4, Canada.,Department of Human Genetics, McGill University, Montréal, Québec, Canada
| | - Timothy E Kennedy
- Montreal Neurological Institute, McGill University, 3801 University Street, room 622, Montréal, Québec, H3A 2B4, Canada
| | | | - Geneviève Bernard
- Departments of Neurology and Neurosurgery, and Pediatrics, McGill University, Montreal, Canada.,Department of Medical Genetics, Montreal Children's Hospital, McGill University Health Center, Montreal, Canada.,Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, Canada
| | - Martin Teichmann
- INSERM U1212 - CNRS UMR5320, Université de Bordeaux, Bordeaux, France
| | - Benoit Coulombe
- Translational Proteomics Laboratory, Institut de recherches cliniques de Montréal (IRCM), Montréal, Québec, Canada.,Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, Québec, Canada
| | - Ian M Willis
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Claudia L Kleinman
- Department of Human Genetics, McGill University, Montréal, Québec, Canada.,Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada
| | - Bernard Brais
- Montreal Neurological Institute, McGill University, 3801 University Street, room 622, Montréal, Québec, H3A 2B4, Canada. .,Department of Human Genetics, McGill University, Montréal, Québec, Canada.
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27
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Thiffault I, Bernard G. Expert opinion and caution are imperative for interpretation of next generation sequencing data. Eur J Med Genet 2016; 59:519-21. [PMID: 27535217 DOI: 10.1016/j.ejmg.2016.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 08/08/2016] [Indexed: 11/29/2022]
Abstract
We comment on the recent publication by Khalifa and Naffa who are reporting a young girl with variants in both WDR45 and POLR3A, which they state contribute to her clinical manifestations. We are arguing in this letter that the clinical, MRI, and genetics findings are not compatible with 4H leukodystrophy and that this patient is not affected by this condition.
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Affiliation(s)
- Isabelle Thiffault
- Children's Mercy Kansas City, Center for Pediatric Genomic Medicine, Kansas City, MO, USA; University of Missouri-Kansas City School of Medicine, Kansas City, MO, USA
| | - Geneviève Bernard
- Departments of Neurology and Neurosurgery and Pediatrics, McGill University, Montreal, Canada; Department of Medical Genetics, Montreal Children's Hospital, McGill University Health Center, Montreal, Canada; Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, Canada.
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28
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Khalifa M, Naffaa L. Exome sequencing reveals a novel WDR45 frameshift mutation and inherited POLR3A heterozygous variants in a female with a complex phenotype and mixed brain MRI findings. Eur J Med Genet 2015; 58:381-6. [PMID: 26096995 DOI: 10.1016/j.ejmg.2015.05.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 05/26/2015] [Indexed: 11/27/2022]
Abstract
WDR45 and POLR3A are newly recognized genes; each is associated with a distinct neurodegenerative disease. WDR45 is an X-linked gene associated with a dominant form of Neurodegeneration with Brain Iron Accumulation (NBIA), manifested by progressive disabilities, dystonia, cognitive decline, spastic paraplegia, neuropsychiatric abnormalities and iron deposition in the basal ganglia on brain imaging. POLR3A, on the other hand, is an autosomal gene, and its mutations cause a recessive form of a hypomyelination with leukodystrophy disease, also known as 4H syndrome, characterized by congenital Hypomyelination with thinning of the corpus callosum, Hypodontia and Hypogonadotropic Hypogonadism. We report on a female child with severe intellectual disability, aphasia, short stature, ataxia, failure to thrive and structural brain abnormalities. Brain MRI obtained in late infancy showed hypomyelination involving the central periventricular white matter and thinning of the corpus callosum with no evidence of iron accumulation. Brain MRI obtained in childhood showed stable hypomyelination, with progressive iron accumulation in the basal ganglia, in particular in the globus pallidus and substantia nigra. Whole Exome Sequencing (WES) identified a novel WDR45 frameshift deleterious mutation in Exon 9 (c.587-588del) and also revealed three POLR3A missense heterozygous variants. The first is a maternally inherited novel missense variant in exon 4 (c.346A > G). Exon 13 carried two heterozygous missense variants, a maternally inherited variant (c.1724A > T) and a paternally inherited variant (1745G > A). These variants are considered likely damaging. The patient's complex clinical phenotype and mixed brain MRI findings might be attributed to the confounding effects of the expression of these two mutant genes.
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Affiliation(s)
- Mohamed Khalifa
- Department of Medical Genetics and Genomics, Akron Children's Hospital, Akron, OH, USA.
| | - Lena Naffaa
- Department Radiology, Akron Children's Hospital, Akron, OH, USA
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29
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Shimojima K, Shimada S, Tamasaki A, Akaboshi S, Komoike Y, Saito A, Furukawa T, Yamamoto T. Novel compound heterozygous mutations of POLR3A revealed by whole-exome sequencing in a patient with hypomyelination. Brain Dev 2014; 36:315-21. [PMID: 23694757 DOI: 10.1016/j.braindev.2013.04.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 04/16/2013] [Accepted: 04/23/2013] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Congenital white matter disorders are a heterogeneous group of hypomyelination disorders affecting the white matter of the brain. Recently, mutations in the genes encoding the subunits of RNA polymerase III (Pol III), POLR3A and POLR3B, have been identified as new genetic causes for hypomyelinating disorders. METHOD Whole-exome sequencing was applied to identify responsible gene mutations in a 29-year-old female patient showing hypomyelination of unknown cause. To investigate the pathological mechanism underlying the hypomyelination in this patient, the expression level of 7SL RNA, a transcriptional target of Pol III, was analyzed in cultured skin fibroblasts derived from the patient with POLR3A mutations. RESULTS Novel compound heterozygous mutations of POLR3A were identified in the patient, who started to show cerebellar signs at 3 years, lost ambulation at 7 years, and became bedridden at 18 years. Brain magnetic resonance imaging showed severe volume loss in the brainstem, the cerebellum, and the white matter associated with hypomyelination. In addition to hypodontia and hypogonadism, she showed many pituitary hormone-related deficiencies. The expression level of 7SL RNA in cultured skin fibroblasts derived from this patient showed no significant abnormality. CONCLUSION The many pituitary hormone-related deficiencies identified in this patient may be an essential finding for the Pol III-related leukodystrophies spectrum. Further investigation is needed for a better understanding of the disease mechanism.
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Affiliation(s)
- Keiko Shimojima
- Tokyo Women's Medical University Institute for Integrated Medical Sciences, Tokyo 162-8666, Japan
| | - Shino Shimada
- Tokyo Women's Medical University Institute for Integrated Medical Sciences, Tokyo 162-8666, Japan; Department of Pediatrics, Tokyo Women's Medical University, Tokyo 162-8666, Japan
| | - Akiko Tamasaki
- Division of Child Neurology, Faculty of Medicine, Tottori University, Yonago 683-8503, Japan
| | - Shinjiro Akaboshi
- Department of Pediatrics, National Hospital Organization Tottori Medical Center, Tottori 689-0203, Japan
| | - Yuta Komoike
- Department of Hygiene and Public Health, Tokyo Women's Medical University, Tokyo 162-8666, Japan
| | | | - Toru Furukawa
- Tokyo Women's Medical University Institute for Integrated Medical Sciences, Tokyo 162-8666, Japan
| | - Toshiyuki Yamamoto
- Tokyo Women's Medical University Institute for Integrated Medical Sciences, Tokyo 162-8666, Japan.
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30
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Takanashi JI, Osaka H, Saitsu H, Sasaki M, Mori H, Shibayama H, Tanaka M, Nomura Y, Terao Y, Inoue K, Matsumoto N, Barkovich AJ. Different patterns of cerebellar abnormality and hypomyelination between POLR3A and POLR3B mutations. Brain Dev 2014; 36:259-63. [PMID: 23643445 DOI: 10.1016/j.braindev.2013.03.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 03/16/2013] [Accepted: 03/27/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND Mutations of POLR3A and POLR3B have been reported to cause several allelic hypomyelinating disorders, including hypomyelination with hypogonadotropic hypogonadism and hypodontia (4H syndrome). PATIENTS AND METHODS To clarify the difference in MRI between the two genotypes, we reviewed MRI in three patients with POLR3B mutations, and three with POLR3A mutations. RESULTS Though small cerebellar hemispheres and vermis are common MRI findings with both types of mutations, MRI in patients with POLR3B mutations revealed smaller cerebellar structures, especially vermis, than those in POLR3A mutations. MRI also showed milder hypomyelination in patients with POLR3B mutations than those with POLR3A mutations, which might explain milder clinical manifestations. CONCLUSIONS MRI findings are distinct between patients with POLR3A and 3B mutations, and can provide important clues for the diagnosis, as these patients sometimes have no clinical symptoms suggesting 4H syndrome.
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Affiliation(s)
- Jun-ichi Takanashi
- Department of Pediatrics, Kameda Medical Center, Kamogawa, Japan; Department of Radiology, Toho University Sakura Medical Center, Sakura, Japan.
| | - Hitoshi Osaka
- Division of Neurology, Clinical Research Institute, Kanagawa Children's Medical Center, Yokohama, Japan
| | - Hirotomo Saitsu
- Department of Human Genetics, Yokohama City University, Graduate School of Medicine, Yokohama, Japan
| | - Masayuki Sasaki
- Department of Child Neurology, National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Harushi Mori
- Department of Radiology, The University of Tokyo, Tokyo, Japan
| | | | - Manabu Tanaka
- Division of Neurology, Saitama Children's Medical Center, Saitama, Japan
| | | | - Yasuo Terao
- Department of Neurology, The University of Tokyo, Tokyo, Japan
| | - Ken Inoue
- Department of Mental Retardation and Birth Defect Research, National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University, Graduate School of Medicine, Yokohama, Japan
| | - A James Barkovich
- Department of Radiology and Biomedical Imaging, University of California San Francisco, CA, USA
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