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Elmubarak I, Shril S, Mansour B, Bao A, Kolvenbach CM, Kari JA, Shalaby MA, El Desoky S, Hildebrandt F, Schneider R. Recessive variants in MYO1C as a potential novel cause of proteinuric kidney disease. Pediatr Nephrol 2024:10.1007/s00467-024-06426-1. [PMID: 38904753 DOI: 10.1007/s00467-024-06426-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 05/03/2024] [Accepted: 05/20/2024] [Indexed: 06/22/2024]
Abstract
BACKGROUND Steroid-resistant nephrotic syndrome is the second leading cause of chronic kidney disease among patients < 25 years of age. Through exome sequencing, identification of > 65 monogenic causes has revealed insights into disease mechanisms of nephrotic syndrome (NS). METHODS To elucidate novel monogenic causes of NS, we combined homozygosity mapping with exome sequencing in a worldwide cohort of 1649 pediatric patients with NS. RESULTS We identified homozygous missense variants in MYO1C in two unrelated children with NS (c.292C > T, p.R98W; c.2273 A > T, p.K758M). We evaluated publicly available kidney single-cell RNA sequencing datasets and found MYO1C to be predominantly expressed in podocytes. We then performed structural modeling for the identified variants in PyMol using aligned shared regions from two available partial structures of MYO1C (4byf and 4r8g). In both structures, calmodulin, a common regulator of myosin activity, is shown to bind to the IQ motif. At both residue sites (K758; R98), there are ion-ion interactions stabilizing intradomain and ligand interactions: R98 binds to nearby D220 within the myosin motor domain and K758 binds to E14 on a calmodulin molecule. Variants of these charged residues to non-charged amino acids could ablate these ionic interactions, weakening protein structure and function establishing the impact of these variants. CONCLUSION We here identified recessive variants in MYO1C as a potential novel cause of NS in children.
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Affiliation(s)
- Izzeldin Elmubarak
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Shirlee Shril
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Bshara Mansour
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Aaron Bao
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Caroline M Kolvenbach
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Institute of Anatomy, Medical Faculty, University of Bonn, Bonn, Germany
| | - Jameela A Kari
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
- Pediatric Nephrology Center of Excellence, King Abdulaziz University Hospital, Jeddah, Saudi Arabia
| | - Mohamed A Shalaby
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
- Pediatric Nephrology Center of Excellence, King Abdulaziz University Hospital, Jeddah, Saudi Arabia
| | - Sherif El Desoky
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
- Pediatric Nephrology Center of Excellence, King Abdulaziz University Hospital, Jeddah, Saudi Arabia
| | - Friedhelm Hildebrandt
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ronen Schneider
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
- Division of Nephrology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA.
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2
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Liu PJ, Sayeeda K, Zhuang C, Krendel M. Roles of myosin 1e and the actin cytoskeleton in kidney functions and familial kidney disease. Cytoskeleton (Hoboken) 2024. [PMID: 38708443 DOI: 10.1002/cm.21861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 03/21/2024] [Accepted: 04/04/2024] [Indexed: 05/07/2024]
Abstract
Mammalian kidneys are responsible for removing metabolic waste and maintaining fluid and electrolyte homeostasis via selective filtration. One of the proteins closely linked to selective renal filtration is myosin 1e (Myo1e), an actin-dependent molecular motor found in the specialized kidney epithelial cells involved in the assembly and maintenance of the renal filter. Point mutations in the gene encoding Myo1e, MYO1E, have been linked to familial kidney disease, and Myo1e knockout in mice leads to the disruption of selective filtration. In this review, we discuss the role of the actin cytoskeleton in renal filtration, the known and hypothesized functions of Myo1e, and the possible explanations for the impact of MYO1E mutations on renal function.
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Affiliation(s)
- Pei-Ju Liu
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Kazi Sayeeda
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Cindy Zhuang
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Mira Krendel
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
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3
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Elmubarak I, Shril S, Mansour B, Bao A, Kolvenbach C, Desoky SE, Shalaby M, Kari J, Hildebrandt F, Schneider R. Recessive variants in MYO1C as a potential novel cause of proteinuric kidney disease. RESEARCH SQUARE 2024:rs.3.rs-4183332. [PMID: 38659911 PMCID: PMC11042399 DOI: 10.21203/rs.3.rs-4183332/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Background Steroid-resistant nephrotic syndrome is the second leading cause of chronic kidney disease among patients <25 years of age. Through whole exome sequencing, identification of >65 monogenic causes has rendered insights into disease mechanisms of nephrotic syndrome. Methods To elucidate novel monogenic causes of NS, we combined homozygosity mapping with ES in a worldwide cohort of 1649 pediatric patients with NS. Results We identified homozygous missense variants in MYO1C in two unrelated children with nephrotic syndrome (c.292C>T, p.R98W; c.2273 A>T, p.K758M). We evaluated publicly available kidney single-cell RNA sequencing datasets and found MYO1Cto be predominantly expressed in podocytes. We then performed structural modeling in molecular viewer PyMol using the super function aligning shared regions within both partial structures of MYO1C (4byf and 4r8g). In both structures, calmodulin, a common regulator of myosin activity, is shown to bind to the IQ motif. At both residue sites (K758; R98), there are ion-ion interactions stabilizing intradomain and ligand interactions: R98 binds to nearby D220 within the Myosin Motor Domain and K758 binds to E14 on a calmodulin molecule. Variants of these charged residues to non-charged amino acids could ablate these ionic interactions, weakening protein structure and function establishing the impact of these variants. Conclusion We here identified recessive variants in MYO1C as a potential novel cause of nephrotic syndrome in children.
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Affiliation(s)
| | - Shirlee Shril
- Boston Childrens Hospital: Boston Children's Hospital
| | | | - Aaron Bao
- Boston Childrens Hospital: Boston Children's Hospital
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Buerger F, Salmanullah D, Liang L, Gauntner V, Krueger K, Qi M, Sharma V, Rubin A, Ball D, Lemberg K, Saida K, Merz LM, Sever S, Issac B, Sun L, Guerrero-Castillo S, Gomez AC, McNulty MT, Sampson MG, Al-Hamed MH, Saleh MM, Shalaby M, Kari J, Fawcett JP, Hildebrandt F, Majmundar AJ. Recessive variants in the intergenic NOS1AP-C1orf226 locus cause monogenic kidney disease responsive to anti-proteinuric treatment. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.03.17.24303374. [PMID: 38562757 PMCID: PMC10984069 DOI: 10.1101/2024.03.17.24303374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
In genetic disease, an accurate expression landscape of disease genes and faithful animal models will enable precise genetic diagnoses and therapeutic discoveries, respectively. We previously discovered that variants in NOS1AP , encoding nitric oxide synthase 1 (NOS1) adaptor protein, cause monogenic nephrotic syndrome (NS). Here, we determined that an intergenic splice product of N OS1AP / Nos1ap and neighboring C1orf226/Gm7694 , which precludes NOS1 binding, is the predominant isoform in mammalian kidney transcriptional and proteomic data. Gm7694 -/- mice, whose allele exclusively disrupts the intergenic product, developed NS phenotypes. In two human NS subjects, we identified causative NOS1AP splice variants, including one predicted to abrogate intergenic splicing but initially misclassified as benign based on the canonical transcript. Finally, by modifying genetic background, we generated a faithful mouse model of NOS1AP -associated NS, which responded to anti-proteinuric treatment. This study highlights the importance of intergenic splicing and a potential treatment avenue in a mendelian disorder.
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Pantel D, Mertens ND, Schneider R, Hölzel S, Kari JA, Desoky SE, Shalaby MA, Lim TY, Sanna-Cherchi S, Shril S, Hildebrandt F. Copy number variation analysis in 138 families with steroid-resistant nephrotic syndrome identifies causal homozygous deletions in PLCE1 and NPHS2 in two families. Pediatr Nephrol 2024; 39:455-461. [PMID: 37670083 PMCID: PMC10979458 DOI: 10.1007/s00467-023-06134-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 07/06/2023] [Accepted: 08/10/2023] [Indexed: 09/07/2023]
Abstract
BACKGROUND Steroid-resistant nephrotic syndrome (SRNS) is the second most common cause of kidney failure in children and adults under the age of 20 years. Previously, we were able to detect by exome sequencing (ES) a known monogenic cause of SRNS in 25-30% of affected families. However, ES falls short of detecting copy number variants (CNV). Therefore, we hypothesized that causal CNVs could be detected in a large SRNS cohort. METHODS We performed genome-wide single nucleotide polymorphism (SNP)-based CNV analysis on a cohort of 138 SRNS families, in whom we previously did not identify a genetic cause through ES. We evaluated ES and CNV data for variants in 60 known SRNS genes and in 13 genes in which variants are known to cause a phenocopy of SRNS. We applied previously published, predefined criteria for CNV evaluation. RESULTS We detected a novel CNV in two genes in 2 out of 138 families (1.5%). The 9,673 bp homozygous deletion in PLCE1 and the 6,790 bp homozygous deletion in NPHS2 were confirmed across the breakpoints by PCR and Sanger sequencing. CONCLUSIONS We confirmed that CNV analysis can identify the genetic cause in SRNS families that remained unsolved after ES. Though the rate of detected CNVs is minor, CNV analysis can be used when there are no other genetic causes identified. Causative CNVs are less common in SRNS than in other monogenic kidney diseases, such as congenital anomalies of the kidneys and urinary tract, where the detection rate was 5.3%. A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- Dalia Pantel
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
- Institute of Human Genetics, Heidelberg University, Heidelberg, Germany
| | - Nils D Mertens
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Ronen Schneider
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Selina Hölzel
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Jameela A Kari
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
- Pediatric Nephrology Center of Excellence, King Abdulaziz University Hospital, Jeddah, Saudi Arabia
| | - Sherif El Desoky
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
- Pediatric Nephrology Center of Excellence, King Abdulaziz University Hospital, Jeddah, Saudi Arabia
| | - Mohamed A Shalaby
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
- Pediatric Nephrology Center of Excellence, King Abdulaziz University Hospital, Jeddah, Saudi Arabia
| | - Tze Y Lim
- Division of Nephrology, Department of Medicine, Columbia University, New York, NY, USA
| | - Simone Sanna-Cherchi
- Division of Nephrology, Department of Medicine, Columbia University, New York, NY, USA
| | - Shirlee Shril
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Friedhelm Hildebrandt
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA.
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6
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Yang Q, Tang D, Gan C, Bai M, Song X, Jiang W, Li Q, Chen Y, Zhang A, Wang M. Novel variants in CRB2 targeting the malfunction of slit diaphragm related to focal segmental glomerulosclerosis. Pediatr Nephrol 2024; 39:149-165. [PMID: 37452832 DOI: 10.1007/s00467-023-06087-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 06/01/2023] [Accepted: 06/29/2023] [Indexed: 07/18/2023]
Abstract
BACKGROUND Focal segmental glomerulosclerosis (FSGS) is a leading cause of steroid-resistant nephrotic syndrome (SRNS) that predominantly affects the podocytes. While mutations in genes causing pediatric SRNS have enhanced our understanding of FSGS, the disease's etiology remains complex and poorly understood. METHODS Whole exome sequencing (WES) was performed on a 9-year-old girl with SRNS associated with FSGS (SRNS-FSGS). We analyzed the expression of CRB2, slit diaphragm (SD)-associated proteins, and sphingosine 1-phosphate receptor 1 (S1PR1) in the proband and CRB2 knock-down podocytes. RESULTS In this study, we identified two novel compound heterozygous mutations in the Crumbs homolog 2 (CRB2) gene (c.2905delinsGCCACCTCGCGCTGGCTG, p.T969Afs*179 and c.3268C > G, p.R1090G) in a family with early-onset SRNS-FSGS. Our findings demonstrate that these CRB2 abnormalities were the underlying cause of SRNS-FSGS. CRB2 defects led to the dysfunction of podocyte SD-related proteins, including podocin, nephrin, and zonula occludens-1 (ZO-1), by reducing the phosphorylation level of S1PR1. Interestingly, the podocytic cytoskeleton remained unaffected, as demonstrated by normal expression and localization of synaptopodin. Our study also revealed a secondary decrease in CRB2 expression in idiopathic FSGS patients, indicating that CRB2 mutations may cause FSGS through a previously unknown mechanism involving SD-related proteins. CONCLUSIONS Overall, our findings shed new light on the pathogenesis of SRNS-FSGS and revealed that the novel pathogenic mutations in CRB2 contribute to the development of FSGS through a previously unknown mechanism involving SD-related proteins. A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- Qing Yang
- Pediatric Research Institute, Department of Nephrology Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, People's Republic of China
| | - Dan Tang
- Department of Pediatrics, The Third Hospital of Mianyang, Sichuan Mental Health Center, Mianyang, 621000, Sichuan, China
| | - Chun Gan
- Pediatric Research Institute, Department of Nephrology Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, People's Republic of China
| | - Mi Bai
- Department of Nephrology, State Key Laboratory of Reproductive Medicine, Children's Hospital of Nanjing Medical University, 72 Guangzhou Road, Nanjing, 210008, China
| | - Xiaomei Song
- Pediatric Research Institute, Department of Nephrology Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, People's Republic of China
| | - Wei Jiang
- Pediatric Research Institute, Department of Nephrology Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, People's Republic of China
| | - Qiu Li
- Pediatric Research Institute, Department of Nephrology Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, People's Republic of China
| | - Yaxi Chen
- Centre for Lipid Research & Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, the Second Affiliated Hospital, Chongqing Medical University, Chongqing, People's Republic of China
| | - Aihua Zhang
- Department of Nephrology, State Key Laboratory of Reproductive Medicine, Children's Hospital of Nanjing Medical University, 72 Guangzhou Road, Nanjing, 210008, China
| | - Mo Wang
- Pediatric Research Institute, Department of Nephrology Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, People's Republic of China.
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Gipson DS, Wang CS, Salmon E, Gbadegesin R, Naik A, Sanna-Cherchi S, Fornoni A, Kretzler M, Merscher S, Hoover P, Kidwell K, Saleem M, Riella L, Holzman L, Jackson A, Olabisi O, Cravedi P, Freedman BS, Himmelfarb J, Vivarelli M, Harder J, Klein J, Burke G, Rheault M, Spino C, Desmond HE, Trachtman H. FSGS Recurrence Collaboration: Report of a Symposium. GLOMERULAR DISEASES 2024; 4:1-10. [PMID: 38348154 PMCID: PMC10859699 DOI: 10.1159/000535138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/30/2023] [Indexed: 02/15/2024]
Affiliation(s)
- Debbie S. Gipson
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Chia-Shi Wang
- Department of Pediatrics, Emory University, Atlanta, GA, USA
| | - Eloise Salmon
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Rasheed Gbadegesin
- Department of Medicine, Duke University, Durham, NC, USA
- Department of Pediatrics, Duke University, Durham, NC, USA
| | - Abhijit Naik
- Department of Medicine, University of Michigan, Ann Arbor, MI, USA
| | | | | | - Matthias Kretzler
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | | | - Paul Hoover
- Department of Medicine, Harvard University, Cambridge, MA, USA
| | - Kelley Kidwell
- Department of Biostatistics, University of Michigan, Ann Arbor, MI, USA
| | - Moin Saleem
- Translational Health Sciences, University of Bristol, Bristol, UK
| | - Leonardo Riella
- Department of Medicine, Harvard University, Cambridge, MA, USA
| | - Lawrence Holzman
- Department of Internal Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | - Paolo Cravedi
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | | | - Marina Vivarelli
- Department of Pediatric Subspecialties, Bambino Gesù Children’s Hospital, Rome, Italy
| | - Jennifer Harder
- Department of Internal Medicine, University of Louisville, Louisville, KY, USA
| | - Jon Klein
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - George Burke
- Department of Surgery, University of Miami, Miami, FL, USA
| | - Michelle Rheault
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Cathie Spino
- Department of Biostatistics, University of Michigan, Ann Arbor, MI, USA
| | - Hailey E. Desmond
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Howard Trachtman
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
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8
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Beck LH, Ayoub I, Caster D, Choi MJ, Cobb J, Geetha D, Rheault MN, Wadhwani S, Yau T, Whittier WL. KDOQI US Commentary on the 2021 KDIGO Clinical Practice Guideline for the Management of Glomerular Diseases. Am J Kidney Dis 2023; 82:121-175. [PMID: 37341661 DOI: 10.1053/j.ajkd.2023.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 02/20/2023] [Indexed: 06/22/2023]
Abstract
The KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases represents the first update to this set of recommendations since the initial set of KDIGO guideline recommendations was published in 2012. The pace of growth in our molecular understanding of glomerular disease has quickened and a number of newer immunosuppressive and targeted therapies have been introduced since the original set of guideline recommendations, making such an update necessary. Despite these updates, many areas of controversy remain. In addition, further updates since the publication of KDIGO 2021 have occurred which this guideline does not encompass. With this commentary, the KDOQI work group has generated a chapter-by-chapter companion opinion article that provides commentary specific to the implementation of the KDIGO 2021 guideline in the United States.
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Affiliation(s)
- Laurence H Beck
- Division of Nephrology, Department of Medicine, Chobanian & Avedisian School of Medicine, Boston University, Boston, Massachusetts
| | - Isabelle Ayoub
- Department of Medicine, Division of Nephrology, Wexner Medical, The Ohio State University, Columbus, Ohio
| | - Dawn Caster
- Department of Medicine, School of Medicine, University of Louisville, Louisville, Kentucky
| | | | - Jason Cobb
- Division of Renal Medicine, Department of Medicine, School of Medicine, Emory University, Atlanta, Georgia
| | - Duvuru Geetha
- Division of Nephrology, Johns Hopkins University, Baltimore, Maryland
| | - Michelle N Rheault
- Department of Pediatrics, Division of Pediatric Nephrology, Masonic Children's Hospital, University of Minnesota, Minneapolis, Minnesota
| | - Shikha Wadhwani
- Division of Nephrology and Hypertension, Northwestern University, Chicago, Illinois
| | - Timothy Yau
- Division of Nephrology, Department of Medicine, School of Medicine, Washington University, St. Louis, Missouri
| | - William L Whittier
- Division of Nephrology, Rush University Medical Center, Chicago, Illinois
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9
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Claus LR, Snoek R, Knoers NVAM, van Eerde AM. Review of genetic testing in kidney disease patients: Diagnostic yield of single nucleotide variants and copy number variations evaluated across and within kidney phenotype groups. AMERICAN JOURNAL OF MEDICAL GENETICS. PART C, SEMINARS IN MEDICAL GENETICS 2022; 190:358-376. [PMID: 36161467 PMCID: PMC9828643 DOI: 10.1002/ajmg.c.31995] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 07/02/2022] [Accepted: 08/18/2022] [Indexed: 01/29/2023]
Abstract
Genetic kidney disease comprises a diverse group of disorders. These can roughly be divided in the phenotype groups congenital anomalies of the kidney and urinary tract, ciliopathies, glomerulopathies, stone disorders, tubulointerstitial kidney disease, and tubulopathies. Many etiologies can lead to chronic kidney disease that can progress to end-stage kidney disease. Despite each individual disease being rare, together these genetic disorders account for a large proportion of kidney disease cases. With the introduction of massively parallel sequencing, genetic testing has become more accessible, but a comprehensive analysis of the diagnostic yield is lacking. This review gives an overview of the diagnostic yield of genetic testing across and within the full range of kidney disease phenotypes through a systematic literature search that resulted in 115 included articles. Patient, test, and cohort characteristics that can influence the diagnostic yield are highlighted. Detection of copy number variations and their contribution to the diagnostic yield is described for all phenotype groups. Also, the impact of a genetic diagnosis for a patient and family members, which can be diagnostic, therapeutic, and prognostic, is shown through the included articles. This review will allow clinicians to estimate an a priori probability of finding a genetic cause for the kidney disease in their patients.
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Affiliation(s)
- Laura R. Claus
- Department of GeneticsUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Rozemarijn Snoek
- Department of GeneticsUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Nine V. A. M. Knoers
- Department of GeneticsUniversity Medical Center GroningenGroningenThe Netherlands
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Falcone S, Nicol T, Blease A, Randles MJ, Angus E, Page A, Tam FWK, Pusey CD, Lennon R, Potter PK. A novel model of nephrotic syndrome results from a point mutation in Lama5 and is modified by genetic background. Kidney Int 2022; 101:527-540. [PMID: 34774562 PMCID: PMC8883398 DOI: 10.1016/j.kint.2021.10.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/22/2021] [Accepted: 10/18/2021] [Indexed: 11/22/2022]
Abstract
Nephrotic syndrome is characterized by severe proteinuria, hypoalbuminaemia, edema and hyperlipidaemia. Genetic studies of nephrotic syndrome have led to the identification of proteins playing a crucial role in slit diaphragm signaling, regulation of actin cytoskeleton dynamics and cell-matrix interactions. The laminin α5 chain is essential for embryonic development and, in association with laminin β2 and laminin γ1, is a major component of the glomerular basement membrane, a critical component of the glomerular filtration barrier. Mutations in LAMA5 were recently identified in children with nephrotic syndrome. Here, we have identified a novel missense mutation (E884G) in the uncharacterized L4a domain of LAMA5 where homozygous mice develop nephrotic syndrome with severe proteinuria with histological and ultrastructural changes in the glomerulus mimicking the progression seen in most patients. The levels of LAMA5 are reduced in vivo and the assembly of the laminin 521 heterotrimer significantly reduced in vitro. Proteomic analysis of the glomerular extracellular fraction revealed changes in the matrix composition. Importantly, the genetic background of the mice had a significant effect on aspects of disease progression from proteinuria to changes in podocyte morphology. Thus, our novel model will provide insights into pathologic mechanisms of nephrotic syndrome and pathways that influence the response to a dysfunctional glomerular basement membrane that may be important in a range of kidney diseases.
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Affiliation(s)
- Sara Falcone
- Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Campus, Oxfordshire, UK; Centre for Cellular and Molecular Physiology, University of Oxford, Oxford, UK
| | - Thomas Nicol
- Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Campus, Oxfordshire, UK; British Heart Foundation, Centre of Research Excellence, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Andrew Blease
- Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Campus, Oxfordshire, UK
| | - Michael J Randles
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Elizabeth Angus
- Biomedical Imaging Unit, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Anton Page
- Biomedical Imaging Unit, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Frederick W K Tam
- Centre for Inflammatory Disease, Department of Immunology and Inflammation, Imperial College London, London, UK
| | - Charles D Pusey
- Centre for Inflammatory Disease, Department of Immunology and Inflammation, Imperial College London, London, UK
| | - Rachel Lennon
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Paul K Potter
- Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Campus, Oxfordshire, UK; Department Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, UK.
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11
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Najafi M, Riedhammer KM, Rad A, Torbati PN, Berutti R, Schüle I, Schroda S, Meitinger T, Ćomić J, Bojd SS, Baranzehi T, Shojaei A, Azarfar A, Khazaei MR, Köttgen A, Backofen R, Karimiani EG, Hoefele J, Schmidts M. High detection rate for disease-causing variants in a cohort of 30 Iranian pediatric steroid resistant nephrotic syndrome cases. Front Pediatr 2022; 10:974840. [PMID: 36245711 PMCID: PMC9555279 DOI: 10.3389/fped.2022.974840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 08/11/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Steroid resistant nephrotic syndrome (SRNS) represents a significant renal disease burden in childhood and adolescence. In contrast to steroid sensitive nephrotic syndrome (SSNS), renal outcomes are significantly poorer in SRNS. Over the past decade, extensive genetic heterogeneity has become evident while disease-causing variants are still only identified in 30% of cases in previously reported studies with proportion and type of variants identified differing depending on the age of onset and ethnical background of probands. A genetic diagnosis however can have implications regarding clinical management, including kidney transplantation, extrarenal disease manifestations, and, in some cases, even causal therapy. Genetic diagnostics therefore play an important role for the clinical care of SRNS affected individuals. METHODOLOGY AND RESULTS Here, we performed NPHS2 Sanger sequencing and subsequent exome sequencing in 30 consanguineous Iranian families with a child affected by SRNS with a mean age of onset of 16 months. We identified disease-causing variants and one variant of uncertain significance in 22 families (73%), including variants in NPHS1 (30%), followed by NPHS2 (20%), WT1 (7%) as well as in NUP205, COQ6, ARHGDIA, SGPL1, and NPHP1 in single cases. Eight of these variants have not previously been reported as disease-causing, including four NPHS1 variants and one variant in NPHS2, ARHGDIA, SGPL1, and NPHP1 each. CONCLUSION In line with previous studies in non-Iranian subjects, we most frequently identified disease-causing variants in NPHS1 and NPHS2. While Sanger sequencing of NPHS2 can be considered as first diagnostic step in non-congenital cases, the genetic heterogeneity underlying SRNS renders next-generation sequencing based diagnostics as the most efficient genetic screening method. In accordance with the mainly autosomal recessive inheritance pattern, diagnostic yield can be significantly higher in consanguineous than in outbred populations.
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Affiliation(s)
- Maryam Najafi
- Genome Research Division, Human Genetics Department, Radboud University Medical Center, Nijmegen, Netherlands.,Pediatric Genetics Division, Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, Freiburg University Faculty of Medicine, Freiburg, Germany
| | - Korbinian M Riedhammer
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany.,Department of Nephrology, Klinikum rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
| | - Aboulfazl Rad
- Genome Research Division, Human Genetics Department, Radboud University Medical Center, Nijmegen, Netherlands.,Cellular and Molecular Research Center, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | | | - Riccardo Berutti
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
| | - Isabel Schüle
- Pediatric Genetics Division, Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, Freiburg University Faculty of Medicine, Freiburg, Germany
| | - Sophie Schroda
- Pediatric Genetics Division, Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, Freiburg University Faculty of Medicine, Freiburg, Germany
| | - Thomas Meitinger
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
| | - Jasmina Ćomić
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany.,Department of Nephrology, Klinikum rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
| | - Simin Sadeghi Bojd
- Children and Adolescents Health Research Center, Research Institute of Cellular and Molecular Science in Infectious Diseases, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Tayebeh Baranzehi
- Department of Biology, University of Sistan and Baluchestan, Zahedan, Iran
| | - Azadeh Shojaei
- Department of Medical Genetics and Molecular Biology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Anoush Azarfar
- Pediatric Nephrology, Kidney Transplantation Complications Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mahmood Reza Khazaei
- Department of Pediatrics, Faculty of Medicine, Mashhad Medical Sciences, Islamic Azad University, Mashhad, Iran
| | - Anna Köttgen
- Institute of Genetic Epidemiology, Faculty of Medicine and Medical Center - University of Freiburg, Freiburg, Germany.,Center for Integrative Biological Signaling Studies, University of Freiburg, Freiburg, Germany
| | - Rolf Backofen
- Center for Integrative Biological Signaling Studies, University of Freiburg, Freiburg, Germany.,Bioinformatics Group, Department of Computer Science, University of Freiburg, Freiburg, Germany
| | - Ehsan Ghayoor Karimiani
- Next Generation Genetic Polyclinic, Mashhad, Iran.,Genetics Research Centre, Molecular and Clinical Sciences Institute, St. George's University, London, United Kingdom
| | - Julia Hoefele
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
| | - Miriam Schmidts
- Genome Research Division, Human Genetics Department, Radboud University Medical Center, Nijmegen, Netherlands.,Pediatric Genetics Division, Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, Freiburg University Faculty of Medicine, Freiburg, Germany.,Center for Integrative Biological Signaling Studies, University of Freiburg, Freiburg, Germany
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12
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Tsuji Y, Yamamura T, Nagano C, Horinouchi T, Sakakibara N, Ishiko S, Aoto Y, Rossanti R, Okada E, Tanaka E, Tsugawa K, Okamoto T, Sawai T, Araki Y, Shima Y, Nakanishi K, Nagase H, Matsuo M, Iijima K, Nozu K. Systematic Review of Genotype-Phenotype Correlations in Frasier Syndrome. Kidney Int Rep 2021; 6:2585-2593. [PMID: 34622098 PMCID: PMC8484119 DOI: 10.1016/j.ekir.2021.07.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 07/09/2021] [Accepted: 07/12/2021] [Indexed: 12/22/2022] Open
Abstract
Introduction Frasier syndrome (FS) is a rare inherited kidney disease caused by intron 9 splicing variants of WT1. For wild-type WT1, 2 active splice donor sites in intron 9 cause a mixture of 2 essential transcripts (with or without lysine-threonine-serine [+/KTS or −KTS]), and imbalance of the +KTS/−KTS ratio results in the development of FS. To date, 6 causative intron 9 variants have been identified; however, detailed transcript analysis has not yet been conducted and the genotype-phenotype correlation also remains to be elucidated. Methods We conducted an in vitro minigene splicing assay for 6 reported causative variants and in vivo RNA sequencing to determine the +KTS/−KTS ratio using patients’ samples. We also performed a systematic review of reported FS cases with a description of the renal phenotype. Results The in vitro assay revealed that although all mutant alleles produced −KTS transcripts only, the wild-type allele produced both +KTS and −KTS transcripts at a 1:1 ratio. In vivo RNA sequencing showed that patients’ samples with all heterozygous variants produced similar ratios of +KTS to −KTS (1:3.2−1:3.5) and wild-type kidney showed almost a 1:1 ratio (1:0.85). A systematic review of 126 cases clarified that the median age of developing ESKD was 16 years in all FS patients, and there were no statistically significant differences between the genotypes or sex chromosome karyotypes in terms of the renal survival period. Conclusion Our study suggested no differences in splicing pattern or renal survival period among reported intron 9 variants causative of FS.
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Affiliation(s)
- Yurika Tsuji
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shinya Ishiko
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yuya Aoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Rini Rossanti
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Eri Okada
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Eriko Tanaka
- Department of Pediatrics, Kyorin University School of Medicine, Mitaka, Japan
| | - Koji Tsugawa
- Department of Pediatrics, Hirosaki University Hospital, Hirosaki, Japan
| | - Takayuki Okamoto
- Department of Pediatrics, Hokkaido University Graduate School of Meidicine, Sapporo, Japan
| | - Toshihiro Sawai
- Department of Pediatrics, Shiga University of Medical Science, Shiga, Japan
| | - Yoshinori Araki
- Department of Pediatrics, Hokkaido Medical Center, Sapporo, Japan
| | - Yuko Shima
- Department of Pediatrics, Wakayama Medical University, Wakayama, Japan
| | - Koichi Nakanishi
- Department of Child Health and Welfare (Pediatrics), Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Hiroaki Nagase
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Masafumi Matsuo
- Locomotion Biology Research Center, Kobe Gakuin University, Kobe, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
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13
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Abstract
Almost 25 years have passed since a mutation of a formin gene, DIAPH1, was identified as being responsible for a human inherited disorder: a form of sensorineural hearing loss. Since then, our knowledge of the links between formins and disease has deepened considerably. Mutations of DIAPH1 and six other formin genes (DAAM2, DIAPH2, DIAPH3, FMN2, INF2 and FHOD3) have been identified as the genetic cause of a variety of inherited human disorders, including intellectual disability, renal disease, peripheral neuropathy, thrombocytopenia, primary ovarian insufficiency, hearing loss and cardiomyopathy. In addition, alterations in formin genes have been associated with a variety of pathological conditions, including developmental defects affecting the heart, nervous system and kidney, aging-related diseases, and cancer. This review summarizes the most recent discoveries about the involvement of formin alterations in monogenic disorders and other human pathological conditions, especially cancer, with which they have been associated. In vitro results and experiments in modified animal models are discussed. Finally, we outline the directions for future research in this field.
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Affiliation(s)
| | - Miguel A. Alonso
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, 28049 Madrid, Spain;
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14
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Mann N, Mzoughi S, Schneider R, Kühl SJ, Schanze D, Klämbt V, Lovric S, Mao Y, Shi S, Tan W, Kühl M, Onuchic-Whitford AC, Treimer E, Kitzler TM, Kause F, Schumann S, Nakayama M, Buerger F, Shril S, van der Ven AT, Majmundar AJ, Holton KM, Kolb A, Braun DA, Rao J, Jobst-Schwan T, Mildenberger E, Lennert T, Kuechler A, Wieczorek D, Gross O, Ermisch-Omran B, Werberger A, Skalej M, Janecke AR, Soliman NA, Mane SM, Lifton RP, Kadlec J, Guccione E, Schmeisser MJ, Zenker M, Hildebrandt F. Mutations in PRDM15 Are a Novel Cause of Galloway-Mowat Syndrome. J Am Soc Nephrol 2021; 32:580-596. [PMID: 33593823 PMCID: PMC7920168 DOI: 10.1681/asn.2020040490] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 11/18/2020] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Galloway-Mowat syndrome (GAMOS) is characterized by neurodevelopmental defects and a progressive nephropathy, which typically manifests as steroid-resistant nephrotic syndrome. The prognosis of GAMOS is poor, and the majority of children progress to renal failure. The discovery of monogenic causes of GAMOS has uncovered molecular pathways involved in the pathogenesis of disease. METHODS Homozygosity mapping, whole-exome sequencing, and linkage analysis were used to identify mutations in four families with a GAMOS-like phenotype, and high-throughput PCR technology was applied to 91 individuals with GAMOS and 816 individuals with isolated nephrotic syndrome. In vitro and in vivo studies determined the functional significance of the mutations identified. RESULTS Three biallelic variants of the transcriptional regulator PRDM15 were detected in six families with proteinuric kidney disease. Four families with a variant in the protein's zinc-finger (ZNF) domain have additional GAMOS-like features, including brain anomalies, cardiac defects, and skeletal defects. All variants destabilize the PRDM15 protein, and the ZNF variant additionally interferes with transcriptional activation. Morpholino oligonucleotide-mediated knockdown of Prdm15 in Xenopus embryos disrupted pronephric development. Human wild-type PRDM15 RNA rescued the disruption, but the three PRDM15 variants did not. Finally, CRISPR-mediated knockout of PRDM15 in human podocytes led to dysregulation of several renal developmental genes. CONCLUSIONS Variants in PRDM15 can cause either isolated nephrotic syndrome or a GAMOS-type syndrome on an allelic basis. PRDM15 regulates multiple developmental kidney genes, and is likely to play an essential role in renal development in humans.
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Affiliation(s)
- Nina Mann
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Slim Mzoughi
- Methyltransferases in Development and Disease Group, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore
- Mount Sinai Center for Therapeutics Discovery, Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Ronen Schneider
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Susanne J Kühl
- Institute of Biochemistry and Molecular Biology, Ulm University, Ulm, Germany
| | - Denny Schanze
- Institute of Human Genetics, University Hospital Magdeburg, Magdeburg, Germany
| | - Verena Klämbt
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Svjetlana Lovric
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Youying Mao
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Shasha Shi
- Grenoble Alpes University, National Center for Scientific Research (CNRS), French Alternative Energies and Atomic Energy Commission (CEA), Institute of Structural Biology, Grenoble, France
| | - Weizhen Tan
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Michael Kühl
- Institute of Biochemistry and Molecular Biology, Ulm University, Ulm, Germany
| | - Ana C Onuchic-Whitford
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
- Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Ernestine Treimer
- Institute for Microscopic Anatomy and Neurobiology, University Medical Center, Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Thomas M Kitzler
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Franziska Kause
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Sven Schumann
- Institute for Microscopic Anatomy and Neurobiology, University Medical Center, Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Makiko Nakayama
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Florian Buerger
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Shirlee Shril
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Amelie T van der Ven
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Amar J Majmundar
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | | | - Amy Kolb
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Daniela A Braun
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Jia Rao
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Tilman Jobst-Schwan
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Eva Mildenberger
- Division of Neonatology, University Medical Center, Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Thomas Lennert
- Department of Pediatrics, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Alma Kuechler
- Institute of Human Genetics, University of Duisburg-Essen, Essen, Germany
| | - Dagmar Wieczorek
- Institute of Human Genetics, Faculty of Medicine, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Oliver Gross
- Clinic of Nephrology and Rheumatology, University Medical Center Goettingen, University of Goettingen, Goettingen, Germany
| | - Beate Ermisch-Omran
- Department of Pediatric Nephrology, University Children's Hospital, Münster, Germany
| | - Anja Werberger
- Institute of Biochemistry and Molecular Biology, Ulm University, Ulm, Germany
| | - Martin Skalej
- Institute of Neuroradiology, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Andreas R Janecke
- Department of Pediatrics I, Medical University of Innsbruck, Innsbruck, Austria
| | - Neveen A Soliman
- Department of Pediatrics, Center of Pediatric Nephrology and Transplantation, Kasr Al Ainy School of Medicine, Cairo University, Cairo, Egypt
- The Egyption Group for Orphan Renal Diseases (EGORD), Cairo, Egypt
| | - Shrikant M Mane
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut
| | - Richard P Lifton
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut
- Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, New York
| | - Jan Kadlec
- Grenoble Alpes University, National Center for Scientific Research (CNRS), French Alternative Energies and Atomic Energy Commission (CEA), Institute of Structural Biology, Grenoble, France
| | - Ernesto Guccione
- Methyltransferases in Development and Disease Group, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore
- Mount Sinai Center for Therapeutics Discovery, Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Michael J Schmeisser
- Institute for Microscopic Anatomy and Neurobiology, University Medical Center, Johannes Gutenberg University of Mainz, Mainz, Germany
- Focus Program Translational Neurosciences, University Medical Center, Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Martin Zenker
- Institute of Human Genetics, University Hospital Magdeburg, Magdeburg, Germany
| | - Friedhelm Hildebrandt
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
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15
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Weng PL, Majmundar AJ, Khan K, Lim TY, Shril S, Jin G, Musgrove J, Wang M, Ahram DF, Aggarwal VS, Bier LE, Heinzen EL, Onuchic-Whitford AC, Mann N, Buerger F, Schneider R, Deutsch K, Kitzler TM, Klämbt V, Kolb A, Mao Y, Moufawad El Achkar C, Mitrotti A, Martino J, Beck BB, Altmüller J, Benz MR, Yano S, Mikati MA, Gunduz T, Cope H, Shashi V, Trachtman H, Bodria M, Caridi G, Pisani I, Fiaccadori E, AbuMaziad AS, Martinez-Agosto JA, Yadin O, Zuckerman J, Kim A, John-Kroegel U, Tyndall AV, Parboosingh JS, Innes AM, Bierzynska A, Koziell AB, Muorah M, Saleem MA, Hoefele J, Riedhammer KM, Gharavi AG, Jobanputra V, Pierce-Hoffman E, Seaby EG, O'Donnell-Luria A, Rehm HL, Mane S, D'Agati VD, Pollak MR, Ghiggeri GM, Lifton RP, Goldstein DB, Davis EE, Hildebrandt F, Sanna-Cherchi S. De novo TRIM8 variants impair its protein localization to nuclear bodies and cause developmental delay, epilepsy, and focal segmental glomerulosclerosis. Am J Hum Genet 2021; 108:357-367. [PMID: 33508234 PMCID: PMC7895901 DOI: 10.1016/j.ajhg.2021.01.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 01/11/2021] [Indexed: 12/14/2022] Open
Abstract
Focal segmental glomerulosclerosis (FSGS) is the main pathology underlying steroid-resistant nephrotic syndrome (SRNS) and a leading cause of chronic kidney disease. Monogenic forms of pediatric SRNS are predominantly caused by recessive mutations, while the contribution of de novo variants (DNVs) to this trait is poorly understood. Using exome sequencing (ES) in a proband with FSGS/SRNS, developmental delay, and epilepsy, we discovered a nonsense DNV in TRIM8, which encodes the E3 ubiquitin ligase tripartite motif containing 8. To establish whether TRIM8 variants represent a cause of FSGS, we aggregated exome/genome-sequencing data for 2,501 pediatric FSGS/SRNS-affected individuals and 48,556 control subjects, detecting eight heterozygous TRIM8 truncating variants in affected subjects but none in control subjects (p = 3.28 × 10-11). In all six cases with available parental DNA, we demonstrated de novo inheritance (p = 2.21 × 10-15). Reverse phenotyping revealed neurodevelopmental disease in all eight families. We next analyzed ES from 9,067 individuals with epilepsy, yielding three additional families with truncating TRIM8 variants. Clinical review revealed FSGS in all. All TRIM8 variants cause protein truncation clustering within the last exon between residues 390 and 487 of the 551 amino acid protein, indicating a correlation between this syndrome and loss of the TRIM8 C-terminal region. Wild-type TRIM8 overexpressed in immortalized human podocytes and neuronal cells localized to nuclear bodies, while constructs harboring patient-specific variants mislocalized diffusely to the nucleoplasm. Co-localization studies demonstrated that Gemini and Cajal bodies frequently abut a TRIM8 nuclear body. Truncating TRIM8 DNVs cause a neuro-renal syndrome via aberrant TRIM8 localization, implicating nuclear bodies in FSGS and developmental brain disease.
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Affiliation(s)
- Patricia L Weng
- Division of Pediatric Nephrology, UCLA, Los Angeles, CA 90095, USA
| | - Amar J Majmundar
- Department of Pediatrics, Boston Children's Hospital, Boston, MA 02115, USA
| | - Kamal Khan
- Center for Disease Modeling, Duke University, Durham, NC 27701, USA; Advanced Center for Translational and Genetic Medicine (ACT-GeM), Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, USA
| | - Tze Y Lim
- Division of Nephrology, Columbia University, New York, NY 10032, USA
| | - Shirlee Shril
- Department of Pediatrics, Boston Children's Hospital, Boston, MA 02115, USA
| | - Gina Jin
- Division of Nephrology, Columbia University, New York, NY 10032, USA
| | - John Musgrove
- Center for Disease Modeling, Duke University, Durham, NC 27701, USA; Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, NC 27705, USA
| | - Minxian Wang
- Cardiovascular Disease Initiative, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Medical and Population Genetics Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Dina F Ahram
- Division of Nephrology, Columbia University, New York, NY 10032, USA
| | - Vimla S Aggarwal
- Institute of Genomic Medicine, Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Louise E Bier
- Institute of Genomic Medicine, Columbia University, New York, NY 10032, USA
| | - Erin L Heinzen
- Institute of Genomic Medicine, Columbia University, New York, NY 10032, USA
| | - Ana C Onuchic-Whitford
- Department of Pediatrics, Boston Children's Hospital, Boston, MA 02115, USA; Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Nina Mann
- Department of Pediatrics, Boston Children's Hospital, Boston, MA 02115, USA
| | - Florian Buerger
- Department of Pediatrics, Boston Children's Hospital, Boston, MA 02115, USA
| | - Ronen Schneider
- Department of Pediatrics, Boston Children's Hospital, Boston, MA 02115, USA
| | - Konstantin Deutsch
- Department of Pediatrics, Boston Children's Hospital, Boston, MA 02115, USA
| | - Thomas M Kitzler
- Department of Pediatrics, Boston Children's Hospital, Boston, MA 02115, USA
| | - Verena Klämbt
- Department of Pediatrics, Boston Children's Hospital, Boston, MA 02115, USA
| | - Amy Kolb
- Department of Pediatrics, Boston Children's Hospital, Boston, MA 02115, USA
| | - Youying Mao
- Department of Pediatrics, Boston Children's Hospital, Boston, MA 02115, USA
| | - Christelle Moufawad El Achkar
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Adele Mitrotti
- Division of Nephrology, Columbia University, New York, NY 10032, USA
| | - Jeremiah Martino
- Division of Nephrology, Columbia University, New York, NY 10032, USA
| | - Bodo B Beck
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Janine Altmüller
- Center for Molecular Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany; Cologne Center for Genomics, University of Cologne, 50931 Cologne, Germany
| | | | - Shoji Yano
- Genetics Division, Department of Pediatrics, LAC+USC Medical Center, Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Mohamad A Mikati
- Division of Pediatric Neurology and Developmental Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Talha Gunduz
- Division of Pediatric Neurology and Developmental Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Heidi Cope
- Department of Pediatrics, Division of Medical Genetics. Duke University Medical Center, Durham, NC 27710, USA
| | - Vandana Shashi
- Department of Pediatrics, Division of Medical Genetics. Duke University Medical Center, Durham, NC 27710, USA
| | - Howard Trachtman
- Department of Pediatrics, Division of Nephrology, New York University Langone Health, New York, NY 10016, USA
| | - Monica Bodria
- Division of Nephrology, Dialysis and Transplantation, Istituto di Ricovero e Cura a Carattere Scientifico, Istituto Giannina Gaslini, 16147 Genova GE, Italy
| | - Gianluca Caridi
- Division of Nephrology, Dialysis and Transplantation, Istituto di Ricovero e Cura a Carattere Scientifico, Istituto Giannina Gaslini, 16147 Genova GE, Italy
| | - Isabella Pisani
- U.O. Nefrologia, Azienda Ospedaliero-Universitaria di Parma and Dipartimento di Medicina e Chirurgia, Università di Parma, 43126 Parma PR, Italy
| | - Enrico Fiaccadori
- U.O. Nefrologia, Azienda Ospedaliero-Universitaria di Parma and Dipartimento di Medicina e Chirurgia, Università di Parma, 43126 Parma PR, Italy
| | - Asmaa S AbuMaziad
- Division of Pediatric Nephrology, University of Arizona-Tucson, AZ 85724, USA
| | - Julian A Martinez-Agosto
- Department of Pediatrics, Division of Medical Genetics, UCLA, Los Angeles, CA 90095, USA; Department of Human Genetics, UCLA, Los Angeles, CA 90095, USA; Department of Psychiatry, UCLA, Los Angeles, CA 90095, USA
| | - Ora Yadin
- Division of Pediatric Nephrology, UCLA, Los Angeles, CA 90095, USA
| | - Jonathan Zuckerman
- Department of Pathology and Laboratory Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Arang Kim
- Department of Pediatrics, Division of Medical Genetics, UCLA, Los Angeles, CA 90095, USA
| | | | - Amanda V Tyndall
- Department of Medical Genetics and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Jillian S Parboosingh
- Department of Medical Genetics and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - A Micheil Innes
- Department of Medical Genetics and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Agnieszka Bierzynska
- Bristol Renal, University of Bristol and Bristol Royal Hospital for Children, Bristol BS2 8BJ, UK
| | - Ania B Koziell
- Department of Paediatric Nephrology, Evelina London, London SE1 7EH, UK; Faculty of Life Sciences, King's College London SE1 9RT, UK
| | - Mordi Muorah
- Renal Unit, Birmingham Children's Hospital, Birmingham, B4 6NH, UK
| | - Moin A Saleem
- Bristol Renal, University of Bristol and Bristol Royal Hospital for Children, Bristol BS2 8BJ, UK
| | - Julia Hoefele
- Institute of Human Genetics, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, 81675 Munich, Germany
| | - Korbinian M Riedhammer
- Institute of Human Genetics, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, 81675 Munich, Germany; Department of Nephrology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, 81675 Munich, Germany
| | - Ali G Gharavi
- Division of Nephrology, Columbia University, New York, NY 10032, USA
| | - Vaidehi Jobanputra
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA; New York Genome Center, New York, NY 10013, USA
| | - Emma Pierce-Hoffman
- Broad Center for Mendelian Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA 02142, USA
| | - Eleanor G Seaby
- Broad Center for Mendelian Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA 02142, USA
| | - Anne O'Donnell-Luria
- Department of Pediatrics, Boston Children's Hospital, Boston, MA 02115, USA; Broad Center for Mendelian Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA 02142, USA
| | - Heidi L Rehm
- Broad Center for Mendelian Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA 02142, USA
| | - Shrikant Mane
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA; Yale Center for Mendelian Genomics, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Vivette D D'Agati
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Martin R Pollak
- Division of Nephrology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Gian Marco Ghiggeri
- Division of Nephrology, Dialysis and Transplantation, Istituto di Ricovero e Cura a Carattere Scientifico, Istituto Giannina Gaslini, 16147 Genova GE, Italy
| | - Richard P Lifton
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA; Yale Center for Mendelian Genomics, Yale University School of Medicine, New Haven, CT 06520, USA; Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, NY 10065, USA
| | - David B Goldstein
- Institute of Genomic Medicine, Columbia University, New York, NY 10032, USA
| | - Erica E Davis
- Center for Disease Modeling, Duke University, Durham, NC 27701, USA; Advanced Center for Translational and Genetic Medicine (ACT-GeM), Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, USA; Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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16
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Bayraktar S, Nehrig J, Menis E, Karli K, Janning A, Struk T, Halbritter J, Michgehl U, Krahn MP, Schuberth CE, Pavenstädt H, Wedlich-Söldner R. A Deregulated Stress Response Underlies Distinct INF2-Associated Disease Profiles. J Am Soc Nephrol 2021; 31:1296-1313. [PMID: 32444357 DOI: 10.1681/asn.2019111174] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 03/20/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Monogenic diseases provide favorable opportunities to elucidate the molecular mechanisms of disease progression and improve medical diagnostics. However, the complex interplay between genetic and environmental factors in disease etiologies makes it difficult to discern the mechanistic links between different alleles of a single locus and their associated pathophysiologies. Inverted formin 2 (INF2), an actin regulator, mediates a stress response-calcium mediated actin reset, or CaAR-that reorganizes the actin cytoskeleton of mammalian cells in response to calcium influx. It has been linked to the podocytic kidney disease focal segemental glomerulosclerosis (FSGS), as well as to cases of the neurologic disorder Charcot-Marie-Tooth disease that are accompanied by nephropathy, mostly FSGS. METHODS We used a combination of quantitative live cell imaging and validation in primary patient cells and Drosophila nephrocytes to systematically characterize a large panel of >50 autosomal dominant INF2 mutants that have been reported to cause either FSGS alone or with Charcot-Marie-Tooth disease. RESULTS We found that INF2 mutations lead to deregulated activation of formin and a constitutive stress response in cultured cells, primary patient cells, and Drosophila nephrocytes. We were able to clearly distinguish between INF2 mutations that were linked exclusively to FSGS from those that caused a combination of FSGS and Charcot-Marie-Tooth disease. Furthermore, we were able to identify distinct subsets of INF2 variants that exhibit varying degrees of activation. CONCLUSIONS Our results suggest that CaAR can be used as a sensitive assay for INF2 function and for robust evaluation of diseased-linked variants of formin. More broadly, these findings indicate that cellular profiling of disease-associated mutations has potential to contribute substantially to sequence-based phenotype predictions.
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Affiliation(s)
- Samet Bayraktar
- Institute of Cell Dynamics and Imaging and Cells in Motion Interfaculty Centre, University of Münster, Münster, Germany.,Internal Medicine D, University Hospital Münster, Münster, Germany
| | - Julian Nehrig
- Institute of Cell Dynamics and Imaging and Cells in Motion Interfaculty Centre, University of Münster, Münster, Germany
| | - Ekaterina Menis
- Institute of Cell Dynamics and Imaging and Cells in Motion Interfaculty Centre, University of Münster, Münster, Germany
| | - Kevser Karli
- Medical Cell Biology, Internal Medicine D, University Hospital Münster, Münster, Germany
| | - Annette Janning
- Institute of Cell Dynamics and Imaging and Cells in Motion Interfaculty Centre, University of Münster, Münster, Germany
| | - Thaddäus Struk
- Internal Medicine D, University Hospital Münster, Münster, Germany
| | - Jan Halbritter
- Division of Nephrology, University of Leipzig, Leipzig, Germany
| | - Ulf Michgehl
- Internal Medicine D, University Hospital Münster, Münster, Germany
| | - Michael P Krahn
- Medical Cell Biology, Internal Medicine D, University Hospital Münster, Münster, Germany
| | - Christian E Schuberth
- Institute of Cell Dynamics and Imaging and Cells in Motion Interfaculty Centre, University of Münster, Münster, Germany
| | | | - Roland Wedlich-Söldner
- Institute of Cell Dynamics and Imaging and Cells in Motion Interfaculty Centre, University of Münster, Münster, Germany
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17
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Generation of Monogenic Candidate Genes for Human Nephrotic Syndrome Using 3 Independent Approaches. Kidney Int Rep 2020; 6:460-471. [PMID: 33615071 PMCID: PMC7879125 DOI: 10.1016/j.ekir.2020.11.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 10/22/2020] [Accepted: 11/10/2020] [Indexed: 12/18/2022] Open
Abstract
Introduction Steroid-resistant nephrotic syndrome (SRNS) is the second most common cause of chronic kidney disease during childhood. Identification of 63 monogenic human genes has delineated 12 distinct pathogenic pathways. Methods Here, we generated 2 independent sets of nephrotic syndrome (NS) candidate genes to augment the discovery of additional monogenic causes based on whole-exome sequencing (WES) data from 1382 families with NS. Results We first identified 63 known monogenic causes of NS in mice from public databases and scientific publications, and 12 of these genes overlapped with the 63 known human monogenic SRNS genes. Second, we used a set of 64 genes that are regulated by the transcription factor Wilms tumor 1 (WT1), which causes SRNS if mutated. Thirteen of these WT1-regulated genes overlapped with human or murine NS genes. Finally, we overlapped these lists of murine and WT1 candidate genes with our list of 120 candidate genes generated from WES in 1382 NS families, to identify novel candidate genes for monogenic human SRNS. Using this approach, we identified 7 overlapping genes, of which 3 genes were shared by all datasets, including SYNPO. We show that loss-of-function of SYNPO leads to decreased CDC42 activity and reduced podocyte migration rate, both of which are rescued by overexpression of wild-type complementary DNA (cDNA), but not by cDNA representing the patient mutation. Conclusion Thus, we identified 3 novel candidate genes for human SRNS using 3 independent, nonoverlapping hypotheses, and generated functional evidence for SYNPO as a novel potential monogenic cause of NS.
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18
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Schneider R, Deutsch K, Hoeprich GJ, Marquez J, Hermle T, Braun DA, Seltzsam S, Kitzler TM, Mao Y, Buerger F, Majmundar AJ, Onuchic-Whitford AC, Kolvenbach CM, Schierbaum L, Schneider S, Halawi AA, Nakayama M, Mann N, Connaughton DM, Klämbt V, Wagner M, Riedhammer KM, Renders L, Katsura Y, Thumkeo D, Soliman NA, Mane S, Lifton RP, Shril S, Khokha MK, Hoefele J, Goode BL, Hildebrandt F. DAAM2 Variants Cause Nephrotic Syndrome via Actin Dysregulation. Am J Hum Genet 2020; 107:1113-1128. [PMID: 33232676 DOI: 10.1016/j.ajhg.2020.11.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 11/05/2020] [Indexed: 01/10/2023] Open
Abstract
The discovery of >60 monogenic causes of nephrotic syndrome (NS) has revealed a central role for the actin regulators RhoA/Rac1/Cdc42 and their effectors, including the formin INF2. By whole-exome sequencing (WES), we here discovered bi-allelic variants in the formin DAAM2 in four unrelated families with steroid-resistant NS. We show that DAAM2 localizes to the cytoplasm in podocytes and in kidney sections. Further, the variants impair DAAM2-dependent actin remodeling processes: wild-type DAAM2 cDNA, but not cDNA representing missense variants found in individuals with NS, rescued reduced podocyte migration rate (PMR) and restored reduced filopodia formation in shRNA-induced DAAM2-knockdown podocytes. Filopodia restoration was also induced by the formin-activating molecule IMM-01. DAAM2 also co-localizes and co-immunoprecipitates with INF2, which is intriguing since variants in both formins cause NS. Using in vitro bulk and TIRF microscopy assays, we find that DAAM2 variants alter actin assembly activities of the formin. In a Xenopus daam2-CRISPR knockout model, we demonstrate actin dysregulation in vivo and glomerular maldevelopment that is rescued by WT-DAAM2 mRNA. We conclude that DAAM2 variants are a likely cause of monogenic human SRNS due to actin dysregulation in podocytes. Further, we provide evidence that DAAM2-associated SRNS may be amenable to treatment using actin regulating compounds.
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19
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Saeed B. Genetic screening in children with challenging nephrotic syndrome. SAUDI JOURNAL OF KIDNEY DISEASES AND TRANSPLANTATION 2020; 31:1189-1197. [PMID: 33565430 DOI: 10.4103/1319-2442.308327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Genetic screening paradigms for the nephrotic syndrome (NS) in the developed world are well established; however, screening in developing countries has received only minor attention. We retrospectively analyzed a cohort of all children who underwent genetic testing for challenging NS from our registry in the 10-year interval from 2000 to 2010 and based on 58 patients aged 0-12 years with at least one of the following clinical diagnosis: Nonsyndromic steroid-resistant nephrotic syndrome (SRNS), familial NS, and congenital NS. Of these, 23 patients (~40%) had a history of familial disease occurrence. All cases were screened for NPHS2 and WT1 mutations by direct sequencing of all exons of the genes. In addition, all patients who were diagnosed during the first three months of life were screened for NPHS1 mutations too. A genetic disease cause was identified in 12 patients (20.7%); of these, five novel mutations, all in NPHS2 accounting for 42% of all mutations and 9% of the cohort. Nine patients were found to have NPHS2 mutations. Only one case with SRNS had a mutation in WT1. Of the five congenital NS, two cases were found to have NPHS1 mutations and one case with NPHS2 mutation. Therefore, mutations in NPHS2 were the most commonly identified and explained in 15.5% of the screened patients and WT1 mutation in 1.7% of cases, whereas NPHS1 mutations were found in 40% of congenital NS cases. A genetic disease cause was identified in 20.7% of the screened patients. Among 12 identified mutations, abnormalities in NPHS2 (n = 9) were most commonly identified.
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Affiliation(s)
- Bassam Saeed
- Farah Association for Child with Kidney Disease, Damascus, Syria
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20
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Labat-de-Hoz L, Alonso MA. The formin INF2 in disease: progress from 10 years of research. Cell Mol Life Sci 2020; 77:4581-4600. [PMID: 32451589 PMCID: PMC11104792 DOI: 10.1007/s00018-020-03550-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 05/04/2020] [Accepted: 05/13/2020] [Indexed: 02/07/2023]
Abstract
Formins are a conserved family of proteins that primarily act to form linear polymers of actin. Despite their importance to the normal functioning of the cytoskeleton, for a long time, the only two formin genes known to be a genetic cause of human disorders were DIAPH1 and DIAPH3, whose mutation causes two distinct forms of hereditary deafness. In the last 10 years, however, the formin INF2 has emerged as an important target of mutations responsible for the appearance of focal segmental glomerulosclerosis, which are histological lesions associated with glomerulus degeneration that often leads to end-stage renal disease. In some rare cases, focal segmental glomerulosclerosis concurs with Charcot-Marie-Tooth disease, which is a degenerative neurological disorder affecting peripheral nerves. All known INF2 gene mutations causing disease map to the exons encoding the amino-terminal domain. In this review, we summarize the structure, biochemical features and functions of INF2, conduct a systematic and comprehensive analysis of the pathogenic INF2 mutations, including a detailed study exon-by-exon of patient cases and mutations, address the impact of the pathogenic mutations on the structure, regulation and known functions of INF2, draw a series of conclusions that could be useful for INF2-related disease diagnosis, and suggest lines of research for future work on the molecular mechanisms by which INF2 causes disease.
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Affiliation(s)
- Leticia Labat-de-Hoz
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid, Spain
| | - Miguel A Alonso
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid, Spain.
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21
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Connaughton DM, Hildebrandt F. Personalized medicine in chronic kidney disease by detection of monogenic mutations. Nephrol Dial Transplant 2020; 35:390-397. [PMID: 30809662 DOI: 10.1093/ndt/gfz028] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 01/08/2019] [Indexed: 12/18/2022] Open
Abstract
A large fraction of early-onset chronic kidney disease (CKD) is known to be monogenic in origin. To date, ∼450 monogenic (synonymous with single-gene disorders) genes, if mutated, are known to cause CKD, explaining ∼30% of cases in pediatric cohorts and ∼5-30% in adult cohorts. However, there are likely hundreds of additional monogenic nephropathy genes that may be revealed by whole-exome or -genome sequencing. Although the discovery of novel CKD-causing genes has accelerated, significant challenges in adult populations remain due to broad phenotypic heterogeneity together with variable expressivity, incomplete penetrance or age-related penetrance of these genes. Here we give an overview of the currently known monogenic causes for human CKD. We also describe how next-generation sequencing facilitates rapid molecular genetic diagnostics in individuals with suspected genetic kidney disease. In an era of precision medicine, understanding the utility of genetic testing in individuals with a suspected inherited nephropathy has important diagnostic and prognostic implications. Detection of monogenic causes of CKD permits molecular genetic diagnosis for patients and families and opens avenues for personalized treatment strategies for CKD. As an example, detection of a pathogenic mutation in the gene HNF1B not only allows for the formal diagnosis of CKD, but can also facilitate screening for additional extrarenal manifestations of disease, such as maturity-onset diabetes of youth, subclinical abnormal liver function tests, neonatal cholestasis and pancreatic hypoplasia. It also provides the driving force towards a better understanding of disease pathogenesis, potentially facilitating targeted new therapies for individuals with CKD.
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Affiliation(s)
- Dervla M Connaughton
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Friedhelm Hildebrandt
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Boston, MA, USA
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22
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Wang M, Wang R, He X, Yu M, Xia Z, Gao C. Two Children With Novel TRPC6 Spontaneous Missense Mutations and Atypical Phenotype: A Case Report and Literature Review. Front Pediatr 2020; 8:269. [PMID: 32509715 PMCID: PMC7249804 DOI: 10.3389/fped.2020.00269] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 04/29/2020] [Indexed: 01/21/2023] Open
Abstract
Background: The phenotypes of TRPC6 mutations have been reported mainly in familial and sporadic focal segmental glomerulosclerosis (FSGS), which can occur in both adults and children. Herein, we report on two children with novel TRPC6 spontaneous missense mutations associated with immune complex-mediated glomerulonephritis and minor glomerular abnormality (MGA) that showed to be resistant to corticosteroids and other immunosuppressants. Case Presentation: A 9-year-old girl presented with steroid-resistant nephrotic syndrome (SRNS), while another 11-year-old boy developed proteinuria at 7 years old. Treatment with a variety of immunosuppressants had no effect, and the renal biopsy showed immune complex-mediated glomerulonephritis and MGA. No members of their family were clinically affected. Genetic testing was performed in the two patients, revealing two novel spontaneous missense mutations in TRPC6-N110S and P112R. The girl developed end-stage renal disease (ESRD) 5 months after onset while the boy continued to have sub-nephrotic range proteinuria and normal creatinine. Conclusions: Two novel TRPC6 mutations were associated with the atypical phenotype-immune complex-mediated glomerulonephritis and MGA, rather than FSGS as previously reported. Their rates of disease progression are different. Genetic testing is helpful to identify the etiology and avoid the side effects brought on by immunosuppressants.
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Affiliation(s)
- Meiqiu Wang
- Department of Pediatrics, Jinling Hospital, The First School of Clinical Medicine, Southern Medical University, Nanjing, China
| | - Ren Wang
- Department of Pediatrics, Jinling Hospital, Nanjing Medical University, Nanjing, China
| | - Xu He
- Department of Pediatrics, Jinling Hospital, Nanjing, China
| | - Min Yu
- Department of Pediatrics, Jinling Hospital, Nanjing Medical University, Nanjing, China.,Department of Neonatology, Taizhou People's Hospital, Taizhou, China
| | - Zhengkun Xia
- Department of Pediatrics, Jinling Hospital, Nanjing, China
| | - Chunlin Gao
- Department of Pediatrics, Jinling Hospital, Nanjing, China
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23
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de Haan A, Eijgelsheim M, Vogt L, Knoers NVAM, de Borst MH. Diagnostic Yield of Next-Generation Sequencing in Patients With Chronic Kidney Disease of Unknown Etiology. Front Genet 2019; 10:1264. [PMID: 31921302 PMCID: PMC6923268 DOI: 10.3389/fgene.2019.01264] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 11/15/2019] [Indexed: 12/11/2022] Open
Abstract
Advances in next-generation sequencing (NGS) techniques, including whole exome sequencing, have facilitated cost-effective sequencing of large regions of the genome, enabling the implementation of NGS in clinical practice. Chronic kidney disease (CKD) is a major contributor to global burden of disease and is associated with an increased risk of morbidity and mortality. CKD can be caused by a wide variety of primary renal disorders. In about one in five CKD patients, no primary renal disease diagnosis can be established. Moreover, recent studies indicate that the clinical diagnosis may be incorrect in a substantial number of patients. Both the absence of a diagnosis or an incorrect diagnosis can have therapeutic implications. Genetic testing might increase the diagnostic accuracy in patients with CKD, especially in patients with unknown etiology. The diagnostic utility of NGS has been shown mainly in pediatric CKD cohorts, while emerging data suggest that genetic testing can also be a valuable diagnostic tool in adults with CKD. In addition to its implications for unexplained CKD, NGS can contribute to the diagnostic process in kidney diseases with an atypical presentation, where it may lead to reclassification of the primary renal disease diagnosis. So far, only a few studies have reported on the diagnostic yield of NGS-based techniques in patients with unexplained CKD. Here, we will discuss the potential diagnostic role of gene panels and whole exome sequencing in pediatric and adult patients with unexplained and atypical CKD.
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Affiliation(s)
- Amber de Haan
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Mark Eijgelsheim
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Liffert Vogt
- Section Nephrology, Amsterdam Cardiovascular Sciences, Department of Internal Medicine, Amsterdam University Medical Centre, University of Amsterdam, Amsterdam, Netherlands
| | - Nine V. A. M. Knoers
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Martin H. de Borst
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
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24
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-254C>G SNP in the TRPC6 Gene Promoter Influences Its Expression via Interaction with the NF- κB Subunit RELA in Steroid-Resistant Nephrotic Syndrome Children. Int J Genomics 2019; 2019:2197837. [PMID: 31281825 PMCID: PMC6590578 DOI: 10.1155/2019/2197837] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 03/07/2019] [Accepted: 04/17/2019] [Indexed: 12/18/2022] Open
Abstract
This study is aimed at exploring the mechanism by which the −254C>G single nucleotide polymorphism (SNP) on the transient receptor potential cation channel 6 (TRPC6) gene promoter could increase its activation in steroid-resistant nephrotic syndrome children of China. Plasmids containing the TRPC6 promoter region (with the −254C or G allele) were constructed and then transfected into human embryonic kidney (HEK) 293T cells and human podocytes. Luciferase assays were used to test the promoter activity in both cell lines with or without tumor necrosis factor-α (TNF-α) treatment, and chromatin immunoprecipitation-polymerase chain reaction (ChIP-PCR) analysis was used to verify the transcription factor that could bind to this mutant sequence. Luciferase results indicate that the activity of the mutant promoter was greater than that of the normal promoter of the TRPC6 gene in both cell lines. We further predicted and verified that this variation was mediated by the nuclear factor kappa B (NF-κB) subunit RELA, and TNF-α significantly enhanced the transcription activity of TRPC6 with the −254G allele. In conclusion, the −254C>G SNP is a gain-of-function variation of the TRPC6 gene, and it is also an early and effective factor for predicting steroid-resistant nephrotic syndrome (SRNS) in Chinese children.
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25
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Jobst-Schwan T, Hoogstraten CA, Kolvenbach CM, Schmidt JM, Kolb A, Eddy K, Schneider R, Ashraf S, Widmeier E, Majmundar AJ, Hildebrandt F. Corticosteroid treatment exacerbates nephrotic syndrome in a zebrafish model of magi2a knockout. Kidney Int 2019; 95:1079-1090. [PMID: 31010479 DOI: 10.1016/j.kint.2018.12.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/21/2018] [Accepted: 12/13/2018] [Indexed: 01/31/2023]
Abstract
Recently, recessive mutations of MAGI2 were identified as a cause of steroid-resistant nephrotic syndrome (SRNS) in humans and mice. To further delineate the pathogenesis of MAGI2 loss of function, we generated stable knockout lines for the two zebrafish orthologues magi2a and magi2b by CRISPR/Cas9. We also developed a novel assay for the direct detection of proteinuria in zebrafish independent of transgenic background. Whereas knockout of magi2b did not yield a nephrotic syndrome phenotype, magi2a-/- larvae developed ascites, periorbital edema, and proteinuria, as indicated by increased excretion of low molecular weight protein. Electron microscopy demonstrated extensive podocyte foot process effacement. As in human SRNS, we observed genotype/phenotype correlation, with edema onset occurring earlier in zebrafish with truncating alleles (5-6 days post fertilization) versus hypomorphic alleles (19-20 days post fertilization). Paradoxically, corticosteroid treatment exacerbated the phenotype, with earlier onset of edema. In contrast, treatment with cyclosporine A or tacrolimus had no significant effect. Although RhoA signaling has been implicated as a downstream mediator of MAGI2 activity, targeting of the RhoA pathway did not modify the nephrotic syndrome phenotype. In the first CRISPR/Cas9 zebrafish knockout model of SRNS, we found that corticosteroids may have a paradoxical effect in the setting of specific genetic mutations.
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Affiliation(s)
- Tilman Jobst-Schwan
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Charlotte A Hoogstraten
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Caroline M Kolvenbach
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Johanna Magdalena Schmidt
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Amy Kolb
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Kaitlyn Eddy
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Ronen Schneider
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Shazia Ashraf
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Eugen Widmeier
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Amar J Majmundar
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Friedhelm Hildebrandt
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
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26
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Mann N, Braun DA, Amann K, Tan W, Shril S, Connaughton DM, Nakayama M, Schneider R, Kitzler TM, van der Ven AT, Chen J, Ityel H, Vivante A, Majmundar AJ, Daga A, Warejko JK, Lovric S, Ashraf S, Jobst-Schwan T, Widmeier E, Hugo H, Mane SM, Spaneas L, Somers MJG, Ferguson MA, Traum AZ, Stein DR, Baum MA, Daouk GH, Lifton RP, Manzi S, Vakili K, Kim HB, Rodig NM, Hildebrandt F. Whole-Exome Sequencing Enables a Precision Medicine Approach for Kidney Transplant Recipients. J Am Soc Nephrol 2019; 30:201-215. [PMID: 30655312 DOI: 10.1681/asn.2018060575] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 11/19/2018] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Whole-exome sequencing (WES) finds a CKD-related mutation in approximately 20% of patients presenting with CKD before 25 years of age. Although provision of a molecular diagnosis could have important implications for clinical management, evidence is lacking on the diagnostic yield and clinical utility of WES for pediatric renal transplant recipients. METHODS To determine the diagnostic yield of WES in pediatric kidney transplant recipients, we recruited 104 patients who had received a transplant at Boston Children's Hospital from 2007 through 2017, performed WES, and analyzed results for likely deleterious variants in approximately 400 genes known to cause CKD. RESULTS By WES, we identified a genetic cause of CKD in 34 out of 104 (32.7%) transplant recipients. The likelihood of detecting a molecular genetic diagnosis was highest for patients with urinary stone disease (three out of three individuals), followed by renal cystic ciliopathies (seven out of nine individuals), steroid-resistant nephrotic syndrome (nine out of 21 individuals), congenital anomalies of the kidney and urinary tract (ten out of 55 individuals), and chronic glomerulonephritis (one out of seven individuals). WES also yielded a molecular diagnosis for four out of nine individuals with ESRD of unknown etiology. The WES-related molecular genetic diagnosis had implications for clinical care for five patients. CONCLUSIONS Nearly one third of pediatric renal transplant recipients had a genetic cause of their kidney disease identified by WES. Knowledge of this genetic information can help guide management of both transplant patients and potential living related donors.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Shrikant M Mane
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut; and
| | | | | | | | | | | | | | | | - Richard P Lifton
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut; and.,Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, New York
| | - Shannon Manzi
- Department of Genetics and Genomics, Department of Pharmacy, and
| | - Khashayar Vakili
- Department of Surgery, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Heung Bae Kim
- Department of Surgery, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
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Bezdíčka M, Štolbová Š, Seeman T, Cinek O, Malina M, Šimánková N, Průhová Š, Zieg J. Genetic diagnosis of steroid-resistant nephrotic syndrome in a longitudinal collection of Czech and Slovak patients: a high proportion of causative variants in NUP93. Pediatr Nephrol 2018; 33:1347-1363. [PMID: 29869118 DOI: 10.1007/s00467-018-3950-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 03/12/2018] [Accepted: 03/22/2018] [Indexed: 12/14/2022]
Abstract
BACKGROUND Steroid-resistant nephrotic syndrome (SRNS) has a heterogeneous spectrum of monogenic causes that substantially differ among populations. The aim of this study was to analyse the genetic aetiology of SRNS in Czech and Slovak paediatric patients. METHODS We analysed clinical data from 74 patients (38 boys) with congenital (15%), infant (14%), and childhood-onset (71%) SRNS collected from the Czech Republic and Slovakia from 2000 to 2017 (inclusive). The DNA samples were first analysed by Sanger sequencing (genes NPHS2, NPHS1, and WT1) and then by next generation sequencing (NGS) using a targeted panel of 48 genes previously associated with SRNS. Family segregation of the causative variants was confirmed by Sanger sequencing when possible. RESULTS Genetic diagnosis was established in 28/74 patients (38%) based on findings of pathogenic or likely pathogenic causative variants in genotypes conforming to the expected mode of inheritance. Sanger sequencing diagnosed 26% of patients, whereas second-tier testing by a targeted NGS panel diagnosed a further 12%. Frequent causative genes were NPHS2 (15%), WT1 (9.5%), and surprisingly NUP93 with four (5.4%) unrelated cases. Additional causative genes included COQ2 (two patients), NPHS1, INF2, DGKE, and LMX1B (one patient each). CONCLUSIONS Compared with outright use of NGS, our tiered genetic testing strategy was considerably more rapid and marginally less expensive. Apart from a high aetiological fraction of NPHS2 and WT1 genes, our study has identified an unexpectedly high frequency of a limited set of presumably ancestral causative mutations in NUP93. The results may aid in tailoring testing strategies in Central European populations.
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Affiliation(s)
- Martin Bezdíčka
- Department of Paediatrics, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, V Uvalu 84, Prague, Czech Republic
| | - Šárka Štolbová
- Department of Paediatrics, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, V Uvalu 84, Prague, Czech Republic
| | - Tomáš Seeman
- Department of Paediatrics, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, V Uvalu 84, Prague, Czech Republic
| | - Ondřej Cinek
- Department of Paediatrics, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, V Uvalu 84, Prague, Czech Republic.
| | - Michal Malina
- Department of Paediatrics, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, V Uvalu 84, Prague, Czech Republic
| | - Naděžda Šimánková
- Department of Paediatrics, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, V Uvalu 84, Prague, Czech Republic
| | - Štěpánka Průhová
- Department of Paediatrics, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, V Uvalu 84, Prague, Czech Republic
| | - Jakub Zieg
- Department of Paediatrics, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, V Uvalu 84, Prague, Czech Republic
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Jin YY, Feng BY, Mao JH. The status quo and challenges of genetic diagnosis in children with steroid-resistant nephrotic syndrome. World J Pediatr 2018; 14:105-109. [PMID: 29644498 DOI: 10.1007/s12519-018-0156-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 03/28/2018] [Indexed: 01/12/2023]
Affiliation(s)
- Yan-Yan Jin
- Department of Nephrology, Children's Hospital, Zhejiang University School of Medicine, #57 Zhugan Lane, Hangzhou, 310003, China
| | - Bing-Yu Feng
- Department of Nephrology, Children's Hospital, Zhejiang University School of Medicine, #57 Zhugan Lane, Hangzhou, 310003, China.,Department of Paediatrics, The First People's Hospital of Huzhou, Huzhou, 313000, China
| | - Jian-Hua Mao
- Department of Nephrology, Children's Hospital, Zhejiang University School of Medicine, #57 Zhugan Lane, Hangzhou, 310003, China.
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Martin CE, Jones N. Nephrin Signaling in the Podocyte: An Updated View of Signal Regulation at the Slit Diaphragm and Beyond. Front Endocrinol (Lausanne) 2018; 9:302. [PMID: 29922234 PMCID: PMC5996060 DOI: 10.3389/fendo.2018.00302] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 05/22/2018] [Indexed: 12/11/2022] Open
Abstract
Podocytes are a major component of the glomerular blood filtration barrier, and alterations to the morphology of their unique actin-based foot processes (FP) are a common feature of kidney disease. Adjacent FP are connected by a specialized intercellular junction known as the slit diaphragm (SD), which serves as the ultimate barrier to regulate passage of macromolecules from the blood. While the link between SD dysfunction and reduced filtration selectivity has been recognized for nearly 50 years, our understanding of the underlying molecular circuitry began only 20 years ago, sparked by the identification of NPHS1, encoding the transmembrane protein nephrin. Nephrin not only functions as the core component of the extracellular SD filtration network but also as a signaling scaffold via interactions at its short intracellular region. Phospho-regulation of several conserved tyrosine residues in this region influences signal transduction pathways which control podocyte cell adhesion, shape, and survival, and emerging studies highlight roles for nephrin phospho-dynamics in mechanotransduction and endocytosis. The following review aims to summarize the last 5 years of advancement in our knowledge of how signaling centered at nephrin directs SD barrier formation and function. We further provide insight on promising frontiers in podocyte biology, which have implications for SD signaling in the healthy and diseased kidney.
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