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Li X, Fan J, Fu R, Peng M, He J, Chen Q, Wang S, Chen C. Case report: A novel R246L mutation in the LMX1B homeodomain causes isolated nephropathy in a large Chinese family. Medicine (Baltimore) 2024; 103:e37442. [PMID: 38457557 PMCID: PMC10919518 DOI: 10.1097/md.0000000000037442] [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: 11/29/2023] [Accepted: 02/09/2024] [Indexed: 03/10/2024] Open
Abstract
BACKGROUND Genetic factors contribute to chronic kidney disease (CKD) and end-stage renal disease (ESRD). Advances in genetic testing have enabled the identification of hereditary kidney diseases, including those caused by LMX1B mutations. LMX1B mutations can lead to nail-patella syndrome (NPS) or nail-patella-like renal disease (NPLRD) with only renal manifestations. CASE PRESENTATION The proband was a 13-year-old female who was diagnosed with nephrotic syndrome at the age of 6. Then she began intermittent hormone and drug therapy. When she was 13 years old, she was admitted to our hospital due to sudden chest tightness, which progressed to end-stage kidney disease (ESRD), requiring kidney replacement therapy. Whole-Exome Sequencing (WES) results suggest the presence of LMX1B gene mutation, c.737G > T, p.Arg246Leu. Tracing her family history, we found that her father, grandmother, uncle and 2 cousins all had hematuria, or proteinuria. In addition to the grandmother, a total of 9 members of the family performed WES. The members with kidney involved all carry the mutated gene. Healthy members did not have the mutated gene. It is characterized by co-segregation of genotype and phenotype. We followed the family for 9 year, the father developed ESRD at the age of 50 and started hemodialysis treatment. The rest patients had normal renal function. No extra-renal manifestations associated with NPS were found in any member of the family. CONCLUSIONS This study has successfully identified missense mutation, c.737G > T (p.Arg246Leu) in the homeodomain, which appears to be responsible for isolated nephropathy in the studied family. The arginine to leucine change at codon 246 likely disrupts the DNA-binding homeodomain of LMX1B. Previous research has documented 2 types of mutations at codon R246, namely R246Q and R246P, which are known to cause NPLRD. The newly discovered mutation, R246L, is likely to be another novel mutation associated with NPLRD, thus expanding the range of mutations at the crucial renal-critical codon 246 that contribute to the development of NPLRD. Furthermore, our findings suggest that any missense mutation occurring at the 246th amino acid position within the homeodomain of the LMX1B gene has the potential to lead to NPLRD.
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Affiliation(s)
- Xian Li
- Xinxiang Medical Univeisity, Xinxiang, China
- Puyang Oilfield General Hospital, Puyang, China
| | - Jiaojiao Fan
- The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Rong Fu
- Puyang Oilfield General Hospital, Puyang, China
| | - Ming Peng
- Beijing Chigene Translational Medicine Research Center Co., Ltd, Beijing, China
| | - Jujie He
- Puyang Oilfield General Hospital, Puyang, China
| | | | | | - Chong Chen
- Puyang Oilfield General Hospital, Puyang, China
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Adeva-Andany MM, Carneiro-Freire N. Biochemical composition of the glomerular extracellular matrix in patients with diabetic kidney disease. World J Diabetes 2022; 13:498-520. [PMID: 36051430 PMCID: PMC9329837 DOI: 10.4239/wjd.v13.i7.498] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 04/19/2022] [Accepted: 06/26/2022] [Indexed: 02/06/2023] Open
Abstract
In the glomeruli, mesangial cells produce mesangial matrix while podocytes wrap glomerular capillaries with cellular extensions named foot processes and tether the glomerular basement membrane (GBM). The turnover of the mature GBM and the ability of adult podocytes to repair injured GBM are unclear. The actin cytoskeleton is a major cytoplasmic component of podocyte foot processes and links the cell to the GBM. Predominant components of the normal glomerular extracellular matrix (ECM) include glycosaminoglycans, proteoglycans, laminins, fibronectin-1, and several types of collagen. In patients with diabetes, multiorgan composition of extracellular tissues is anomalous, including the kidney, so that the constitution and arrangement of glomerular ECM is profoundly altered. In patients with diabetic kidney disease (DKD), the global quantity of glomerular ECM is increased. The level of sulfated proteoglycans is reduced while hyaluronic acid is augmented, compared to control subjects. The concentration of mesangial fibronectin-1 varies depending on the stage of DKD. Mesangial type III collagen is abundant in patients with DKD, unlike normal kidneys. The amount of type V and type VI collagens is higher in DKD and increases with the progression of the disease. The GBM contains lower amount of type IV collagen in DKD compared to normal tissue. Further, genetic variants in the α3 chain of type IV collagen may modulate susceptibility to DKD and end-stage kidney disease. Human cellular models of glomerular cells, analyses of human glomerular proteome, and improved microscopy procedures have been developed to investigate the molecular composition and organization of the human glomerular ECM.
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Oe Y, Mishima E, Mori T, Okamoto K, Honkura Y, Nagasawa T, Yoshida M, Sato H, Suzuki J, Ikeda R, Sohara E, Uchida S, Katori Y, Miyazaki M. A Novel Mutation in LMX1B (p.Pro219Ala) Causes Focal Segmental Glomerulosclerosis with Alport Syndrome-like Phenotype. Intern Med 2021; 60:2991-2996. [PMID: 33814499 PMCID: PMC8502659 DOI: 10.2169/internalmedicine.6987-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A 69-year-old woman presented with mild renal dysfunction, proteinuria, and sensorineural hearing loss. A renal biopsy showed focal segmental glomerulosclerosis with thinning of the glomerular basement membrane. There was a positive family history of end-stage kidney disease and hearing loss. Although Alport syndrome was suspected from these features, a genetic test using next-generation sequencer identified a novel missense mutation in LMX1B, c.655C>G: p. (Pro219Ala). In silico analyses predicted the pathogenicity of the mutation. Thus, the present case was diagnosed as LMX1B-associated nephropathy presenting with Alport syndrome-like phenotype, expanding the disease spectrum of LMX1B nephropathy.
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Affiliation(s)
- Yuji Oe
- Division of Nephrology, Endocrinology, and Vascular Medicine, Tohoku University Graduate School of Medicine, Japan
- Department of Community Medical Support, Tohoku Medical Megabank Organization, Tohoku University, Japan
| | - Eikan Mishima
- Division of Nephrology, Endocrinology, and Vascular Medicine, Tohoku University Graduate School of Medicine, Japan
| | - Takayasu Mori
- Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Japan
| | - Koji Okamoto
- Division of Nephrology, Endocrinology, and Vascular Medicine, Tohoku University Graduate School of Medicine, Japan
- Department of Community Medical Support, Tohoku Medical Megabank Organization, Tohoku University, Japan
| | - Yohei Honkura
- Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Japan
| | - Tasuku Nagasawa
- Division of Nephrology, Endocrinology, and Vascular Medicine, Tohoku University Graduate School of Medicine, Japan
| | - Mai Yoshida
- Division of Nephrology, Endocrinology, and Vascular Medicine, Tohoku University Graduate School of Medicine, Japan
| | | | - Jun Suzuki
- Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Japan
| | - Ryoukichi Ikeda
- Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Japan
| | - Eisei Sohara
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Japan
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Japan
| | - Yukio Katori
- Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Japan
| | - Mariko Miyazaki
- Division of Nephrology, Endocrinology, and Vascular Medicine, Tohoku University Graduate School of Medicine, Japan
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4
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Morimoto N, Nagahama K, Mori T, Fujimaru T, Tsuura Y, Terai A, Tanabe M, Otani M, Shioji S, Hirasawa S, Aki S, Aoyagi M, Sohara E, Uchida S, Tanaka H. A Novel LMX1B Variant Identified in a Patient Presenting with Severe Renal Involvement and Thin Glomerular Basement Membrane. Nephron Clin Pract 2021; 145:776-782. [PMID: 34515165 DOI: 10.1159/000518423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 07/09/2021] [Indexed: 11/19/2022] Open
Abstract
We report a case of nail-patella syndrome (NPS) with unusual thinning of the glomerular basement membrane (GBM) associated with a novel heterozygous variant in the LMX1B gene. A 43-year-old female patient with a previous diagnosis of NPS, referred to our hospital for persistent proteinuria, underwent a renal biopsy, which revealed minor glomerular abnormalities. She underwent a second renal biopsy at the age of 56 owing to the presence of persistent proteinuria and decline in serum albumin, meeting the diagnostic criteria for nephrotic syndrome. Light microscopy demonstrated glomerulosclerosis and cystic dilatation of the renal tubules. Notably, electron microscopy revealed unusual thinning of the GBM, which is quite different from typical biopsy findings observed in patients with NPS, characterized by thick GBM with fibrillary material and electron-lucent structures. Comprehensive genetic screening for 168 known genes responsible for inherited kidney diseases using a next-generation sequencing panel identified a novel heterozygous in-frame deletion-insertion (c.723_729delinsCAAC: p.[Ser242_Lys243delinsAsn]) in exon 4 of the LMX1B gene, which may account for the disrupted GBM structure. Further studies are warranted to elucidate the complex genotype-phenotype relationship between LMX1B and proper GBM morphogenesis.
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Affiliation(s)
| | - Kiyotaka Nagahama
- Department of Pathology, Kyorin University School of Medicine, Tokyo, Japan
| | - Takayasu Mori
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takuya Fujimaru
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yukio Tsuura
- Department of Pathology, Yokosuka Kyosai Hospital, Yokosuka, Japan
| | - Ayumi Terai
- Department of Nephrology, Yokosuka Kyosai Hospital, Yokosuka, Japan
| | - Madoka Tanabe
- Department of Nephrology, Yokosuka Kyosai Hospital, Yokosuka, Japan
| | - Megumi Otani
- Department of Nephrology, Yokosuka Kyosai Hospital, Yokosuka, Japan
| | - Shingo Shioji
- Department of Nephrology, Yokosuka Kyosai Hospital, Yokosuka, Japan
| | - Suguru Hirasawa
- Department of Nephrology, Yokosuka Kyosai Hospital, Yokosuka, Japan
| | - Shota Aki
- Department of Nephrology, Yokosuka Kyosai Hospital, Yokosuka, Japan
| | - Makoto Aoyagi
- Department of Nephrology, Yokosuka Kyosai Hospital, Yokosuka, Japan
| | - Eisei Sohara
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hiroyuki Tanaka
- Department of Nephrology, Yokosuka Kyosai Hospital, Yokosuka, Japan
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Shimohata H, Miyake Y, Yoshida Y, Usui J, Mori T, Sohara E, Uchida S, Hirayama K, Kobayashi M. LMX1B-associated nephropathy that showed myelin figures on electron microscopy. CEN Case Rep 2021; 10:588-591. [PMID: 34076843 DOI: 10.1007/s13730-021-00612-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 05/25/2021] [Indexed: 12/25/2022] Open
Abstract
The mutation of LIM homeodomain transcription factor LMX1B gene leads to nail-patella syndrome (NPS), which is characterized by dysplastic nails, hypoplastic patellae, iliac horns and nephropathy. The characteristic renal histological finding of NPS nephropathy is irregular thickening of the glomerular basement membrane with patchy lucent areas, including deposits of bundles of type III collagen fibrils revealed by electron microscopy (EM). Fabry disease is a lysosomal storage disorder caused by a deficiency of α-galactosidase A activity, and the characteristic EM finding is a lamellated membrane structure (myelin figures). We present the case of a male with LMX1B-associated nephropathy (LAN) who showed focal segmental glomerulosclerosis (FSGS) on light microscopy, and myelin figures and slight deposits of collagen fibrils on EM, without findings of glomerular basement membrane abnormality suggestive for NPS. A 21-year-old Japanese-Brazilian man was admitted to hospital for an investigation of the cause of proteinuria and decreased renal function. A renal biopsy was performed to investigate the cause of renal damage. Fabry disease was initially considered, based on the presence of myelin figures on EM, but since he had normal α-galactosidase A activity, this initial diagnosis was denied, and the patient was subsequently diagnosed with FSGS. At 22 years after that renal biopsy, the patient was incidentally diagnosed with LAN when NM_002316:3c.746G > A:p.(Arg249Gln) LMX1B variant was identified in his older brother by a pre-transplantation examination, and the same mutation was confirmed in the patient. Myelin figures revealed by EM might become one of the clues for the diagnosis of LAN.
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Affiliation(s)
- Homare Shimohata
- Department of Nephrology, Tokyo Medical University Ibaraki Medical Center, 3-20-1 Chuo Ami, Inashiki, Ibaraki, 300-0395, Japan.
| | - Yusuke Miyake
- Department of Nephrology, Tsuchiura Kyodo General Hospital, Tsuchiura, Ibaraki, Japan
| | - Yu Yoshida
- Department of Nephrology, Tsuchiura Kyodo General Hospital, Tsuchiura, Ibaraki, Japan
| | - Joichi Usui
- Department of Nephrology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Takayasu Mori
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo, Tokyo, Japan
| | - Eisei Sohara
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo, Tokyo, Japan
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo, Tokyo, Japan
| | - Kouichi Hirayama
- Department of Nephrology, Tokyo Medical University Ibaraki Medical Center, 3-20-1 Chuo Ami, Inashiki, Ibaraki, 300-0395, Japan
| | - Masaki Kobayashi
- Department of Nephrology, Tokyo Medical University Ibaraki Medical Center, 3-20-1 Chuo Ami, Inashiki, Ibaraki, 300-0395, Japan
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Isaranuwatchai S, Chanakul A, Ittiwut C, Srichomthong C, Shotelersuk V, Praditpornsilpa K, Suphapeetiporn K. Whole-Exome Sequencing Solved over 2-Decade Kidney Disease Enigma. Nephron Clin Pract 2021; 145:311-316. [PMID: 33725694 DOI: 10.1159/000514293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 01/03/2021] [Indexed: 11/19/2022] Open
Abstract
Chronic kidney disease of unknown etiology (CKDu) has been a problem in renal practice as indefinite diagnosis may lead to inappropriate management. Here, we report a 54-year-old father diagnosed with CKDu at 33 years old and his 8-year-old son with steroid-resistant nephrotic syndrome. Using whole-exome sequencing, both were found to be heterozygous for c.737G>A (p.Arg246Gln) in LMX1B. The diagnosis of LMX1B-associated nephropathy has led to changes in the treatment plan with appropriate genetic counseling. The previously reported cases with this particular mutation were also reviewed. Most children with LMX1B-associated nephropathy had nonnephrotic proteinuria with normal renal function. Interestingly, our pediatric case presented with steroid-resistant nephrotic syndrome at 8 years old and progressed to ESRD requiring peritoneal dialysis at the age of 15 years. Our report emphasized the need of genetic testing in CKDu for definite diagnosis leading to precise management.
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Affiliation(s)
- Suramath Isaranuwatchai
- Division of Nephrology, Department of Internal Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Ankanee Chanakul
- Division of Nephrology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Chupong Ittiwut
- Department of Pediatrics, Center of Excellence for Medical Genomics, Medical Genomics Cluster, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Excellence Center for Genomics and Precision Medicine, King Chulalongkorn Memorial Hospital, the Thai Red Cross Society, Bangkok, Thailand
| | - Chalurmpon Srichomthong
- Department of Pediatrics, Center of Excellence for Medical Genomics, Medical Genomics Cluster, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Excellence Center for Genomics and Precision Medicine, King Chulalongkorn Memorial Hospital, the Thai Red Cross Society, Bangkok, Thailand
| | - Vorasuk Shotelersuk
- Department of Pediatrics, Center of Excellence for Medical Genomics, Medical Genomics Cluster, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Excellence Center for Genomics and Precision Medicine, King Chulalongkorn Memorial Hospital, the Thai Red Cross Society, Bangkok, Thailand
| | - Kearkiat Praditpornsilpa
- Division of Nephrology, Department of Internal Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand,
| | - Kanya Suphapeetiporn
- Department of Pediatrics, Center of Excellence for Medical Genomics, Medical Genomics Cluster, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Excellence Center for Genomics and Precision Medicine, King Chulalongkorn Memorial Hospital, the Thai Red Cross Society, Bangkok, Thailand
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7
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Lei L, Oh G, Sutherland S, Abra G, Higgins J, Sibley R, Troxell M, Kambham N. Myelin bodies in LMX1B-associated nephropathy: potential for misdiagnosis. Pediatr Nephrol 2020; 35:1647-1657. [PMID: 32356190 DOI: 10.1007/s00467-020-04564-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 03/20/2020] [Accepted: 03/30/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Myelin figures, or zebra bodies, seen on electron microscopy were historically considered pathognomonic of Fabry disease, a rare lysosomal storage disorder caused by alpha-galactosidase A deficiency and associated with X-linked recessive mode of inheritance. More recently, iatrogenic phospholipidosis has emerged as an important alternate cause of myelin figures in the kidney. METHODS We report two families with autosomal dominant nephropathy presenting with proteinuria and microscopic hematuria, and the kidney biopsies were notable for the presence of myelin figures and zebra bodies. RESULTS Laboratory and genetic work-up for Fabry disease was negative. Genetic testing in both families revealed the same heterozygous missense mutation in LMX1B (C.737G>A, p.Arg246Gln). LMX1B mutations are known to cause nail-patella syndrome, featuring dysplastic nails and patella with or without nephropathy, as well as isolated LMX1B-associated nephropathy in the absence of extrarenal manifestations. CONCLUSIONS LMX1B mutation-associated nephropathy should be considered in hereditary cases of proteinuria and/or hematuria, even in the absence of unique glomerular basement membrane changes indicative of nail-patella syndrome. In addition, LMX1B mutation should be included in the differential diagnosis of myelin figures and zebra bodies on kidney biopsy, so as to avoid a misdiagnosis.
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Affiliation(s)
- Li Lei
- Department of Pathology, Stanford University, H2110, 300 Pasteur Drive, Stanford, CA, 94305, USA
| | - Gia Oh
- Randall Children's Hospital, Portland, OR, USA
| | - Scott Sutherland
- Department of Pediatrics & Division of Nephrology, Stanford University, Stanford, CA, USA
| | | | - John Higgins
- Department of Pathology, Stanford University, H2110, 300 Pasteur Drive, Stanford, CA, 94305, USA
| | - Richard Sibley
- Department of Pathology, Stanford University, H2110, 300 Pasteur Drive, Stanford, CA, 94305, USA
| | - Megan Troxell
- Department of Pathology, Stanford University, H2110, 300 Pasteur Drive, Stanford, CA, 94305, USA
| | - Neeraja Kambham
- Department of Pathology, Stanford University, H2110, 300 Pasteur Drive, Stanford, CA, 94305, USA.
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8
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Pinto E Vairo F, Pichurin PN, Fervenza FC, Nasr SH, Mills K, Schmitz CT, Klee EW, Herrmann SM. Nail-patella-like renal disease masquerading as Fabry disease on kidney biopsy: a case report. BMC Nephrol 2020; 21:341. [PMID: 32791958 PMCID: PMC7424659 DOI: 10.1186/s12882-020-02012-3] [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] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 08/06/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Genetic changes in the LIM homeobox transcription factor 1 beta (LMX1B) have been associated with focal segmental glomerulosclerosis (FSGS) without the extra-renal or ultrastructural manifestations of Nail-patella syndrome (NPS) known as Nail-patella-like renal disease (NPLRD). Fabry disease (FD) is an X-linked lysosomal disease caused by the deficiency of alpha-galactosidase A. The classic form of the disease is characterized by acroparesthesia, angiokeratomas, cornea verticillata, hypertrophic cardiomyopathy, strokes, and chronic kidney disease. Podocyte myelin bodies on ultrastructural examination of kidney tissue are very characteristic of FD; however some medications and other conditions may mimic this finding. CASE PRESENTATION Here, we report on a female patient with chronic kidney disease (CKD), positive family history for kidney disease and kidney biopsy showing a FSGS lesion and presence of focal myelin figures within podocytes concerning for FD. However, genetic testing for FD was negative. After comprehensive clinical, biochemical, and genetic evaluation, including whole exome and RNA sequencing, she was ultimately diagnosed with NPLRD. CONCLUSIONS This case illustrates the difficulties of diagnosing atypical forms of rare Mendelian kidney diseases and the role of a multidisciplinary team in an individualized medicine clinic setting in combination with state-of-the-art sequencing technologies to reach a definitive diagnosis.
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Affiliation(s)
- Filippo Pinto E Vairo
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA.,Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Pavel N Pichurin
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA.,Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Fernando C Fervenza
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, 200 First St SW, Rochester, MN, 55905, USA
| | - Samih H Nasr
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Kevin Mills
- UCL Institute of Child Health, Great Ormond Street Hospital, London, UK
| | | | - Eric W Klee
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA.,Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA.,Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.,Department of Health Sciences Research, Mayo Clinic, Rochester, MN, USA
| | - Sandra M Herrmann
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, 200 First St SW, Rochester, MN, 55905, USA.
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9
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Andeen NK, Schleit J, Blosser CD, Dorschner MO, Hisama FM, Smith KD. LMX1B-Associated Nephropathy With Type III Collagen Deposition in the Glomerular and Tubular Basement Membranes. Am J Kidney Dis 2017; 72:296-301. [PMID: 29246420 DOI: 10.1053/j.ajkd.2017.09.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 09/23/2017] [Indexed: 02/08/2023]
Abstract
Variants in the LMX1B gene cause nail-patella syndrome, a rare autosomal dominant disorder characterized by dysplasia of nails, patella and elbow abnormalities, iliac "horns," and glaucoma. We describe an adult man with nephrotic syndrome and no systemic manifestations of nail-patella syndrome at the time of his initial kidney biopsy. His kidney biopsy was initially interpreted as a form of segmental sclerosis with unusual fibrillar deposits. At the time of consideration for kidney transplantation, a family history was notable for end-stage renal disease in 3 generations. Subsequent reanalysis of the initial biopsy showed infiltration of the lamina densa by type III collagen fibrils, and molecular studies identified a pathogenic variant in one allele of LMX1B (a guanine to adenine substitution at nucleoide 737 of the coding sequence [c.737G>A], predicted to result in an arginine to glutamine substitution at amino acid 246 [p.Arg246Gln]). This variant has been described previously in multiple unrelated families who presented with autosomal dominant nephropathy without nail and patellar abnormalities.
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Affiliation(s)
- Nicole K Andeen
- Department of Pathology, University of Washington, Seattle, WA
| | | | - Christopher D Blosser
- Division of Nephrology, Department of Medicine, University of Washington, Seattle, WA
| | - Michael O Dorschner
- Department of Pathology, University of Washington, Seattle, WA; Department of Genome Sciences, University of Washington, Seattle, WA
| | - Fuki Marie Hisama
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA
| | - Kelly D Smith
- Department of Pathology, University of Washington, Seattle, WA.
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10
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Harita Y, Kitanaka S, Isojima T, Ashida A, Hattori M. Spectrum of LMX1B mutations: from nail-patella syndrome to isolated nephropathy. Pediatr Nephrol 2017; 32:1845-1850. [PMID: 27450397 DOI: 10.1007/s00467-016-3462-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 07/04/2016] [Accepted: 07/06/2016] [Indexed: 01/18/2023]
Abstract
Nail-patella syndrome (NPS) is an autosomal-dominant disease caused by LMX1B mutations and is characterized by dysplastic nails, absent or hypoplastic patellae, elbow dysplasia, and iliac horns. Renal involvement is the major determinant of the prognosis for NPS. Patients often present with varying degrees of proteinuria or hematuria, and can occasionally progress to chronic renal failure. Recent genetic analysis has found that some mutations in the homeodomain of LMX1B cause isolated nephropathy without nail, patellar or skeletal abnormality (LMX1B-associated nephropathy). The classic term "nail-patella syndrome" would not represent disease conditions in these cases. This review provides an overview of NPS, and highlights the molecular genetics of NPS nephropathy and LMX1B-associated nephropathy. Our current understanding of LMX1B function in the pathogenesis of NPS and LMX1B-associated nephropathy is also presented, and its downstream regulatory networks discussed. This recent progress provides insights that help to define potential targeted therapeutic strategies for LMX1B-associated diseases.
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Affiliation(s)
- Yutaka Harita
- Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
| | - Sachiko Kitanaka
- Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Tsuyoshi Isojima
- Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Akira Ashida
- Department of Pediatrics, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Motoshi Hattori
- Department of Pediatric Nephrology, Tokyo Women's Medical University, Sinjuku-ku, Tokyo, Japan
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Fu Y, Zhu JY, Richman A, Zhao Z, Zhang F, Ray PE, Han Z. A Drosophila model system to assess the function of human monogenic podocyte mutations that cause nephrotic syndrome. Hum Mol Genet 2017; 26:768-780. [PMID: 28164240 DOI: 10.1093/hmg/ddw428] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Accepted: 12/16/2016] [Indexed: 12/15/2022] Open
Abstract
Many genetic mutations have been identified as monogenic causes of nephrotic syndrome (NS), but important knowledge gaps exist in the roles of these genes in kidney cell biology and renal diseases. More animal models are needed to assess the functions of these genes in vivo, and to determine how they cause NS in a timely manner. Drosophila nephrocytes and human podocytes share striking similarities, but to what degree these known NS genes play conserved roles in nephrocytes remains unknown. Here we systematically studied 40 genes associated with NS, including 7 that have not previously been analysed for renal function in an animal model. We found that 85% of these genes are required for nephrocyte functions, suggesting that a majority of human genes known to be associated with NS play conserved roles in renal function from flies to humans. To investigate functional conservation in more detail, we focused on Cindr, the fly homolog of the human NS gene CD2AP. Silencing Cindr in nephrocytes led to dramatic nephrocyte functional impairment and shortened life span, as well as collapse of nephrocyte lacunar channels and effacement of nephrocyte slit diaphragms. These phenotypes could be rescued by expression of a wild-type human CD2AP gene, but not a mutant allele derived from a patient with CD2AP-associated NS. We conclude that the Drosophila nephrocyte can be used to elucidate clinically relevant molecular mechanisms underlying the pathogenesis of most monogenic forms of NS, and to efficiently generate personalized in vivo models of genetic renal diseases bearing patient-specific mutations.
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Affiliation(s)
- Yulong Fu
- Center for Cancer and Immunology Research, Children's National Health Systems, 111 Michigan Ave. NW, Washington, DC, USA
| | - Jun-Yi Zhu
- Center for Cancer and Immunology Research, Children's National Health Systems, 111 Michigan Ave. NW, Washington, DC, USA
| | - Adam Richman
- Center for Cancer and Immunology Research, Children's National Health Systems, 111 Michigan Ave. NW, Washington, DC, USA
| | - Zhanzheng Zhao
- Department of Nephrology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, People's Republic of China
| | - Fujian Zhang
- Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, People's Republic of China
| | - Patricio E Ray
- Center for Genetic Medicine Research, Children's National Health Systems, 111 Michigan Ave. NW, Washington, DC, USA.,Department of Pediatrics, The George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Zhe Han
- Center for Cancer and Immunology Research, Children's National Health Systems, 111 Michigan Ave. NW, Washington, DC, USA.,Department of Pediatrics, The George Washington University School of Medicine and Health Sciences, Washington, DC, USA
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Dysregulation of WTI (-KTS) is Associated with the Kidney-Specific Effects of the LMX1B R246Q Mutation. Sci Rep 2017; 7:39933. [PMID: 28059119 PMCID: PMC5216339 DOI: 10.1038/srep39933] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 11/28/2016] [Indexed: 01/11/2023] Open
Abstract
Mutations in the LIM homeobox transcription factor 1-beta (LMX1B) are a cause of nail patellar syndrome, a condition characterized by skeletal changes, glaucoma and focal segmental glomerulosclerosis. Recently, a missense mutation (R246Q) in LMX1B was reported as a cause of glomerular pathologies without extra-renal manifestations, otherwise known as nail patella-like renal disease (NPLRD). We have identified two additional NPLRD families with the R246Q mutation, though the mechanisms by which LMX1BR246Q causes a renal-specific phenotype is unknown. In this study, using human podocyte cell lines overexpressing either myc-LMX1BWT or myc-LMX1BR246Q, we observed dominant negative and haploinsufficiency effects of the mutation on the expression of podocyte genes such as NPHS1, GLEPP1, and WT1. Specifically, we observed a novel LMX1BR246Q-mediated downregulation of WT1(−KTS) isoforms in podocytes. In conclusion, we have shown that the renal-specific phenotype associated with the LMX1BR246Q mutation may be due to a dominant negative effect on WT1(−KTS) isoforms that may cause a disruption of the WT1 (−KTS):(+KTS) isoform ratio and a decrease in the expression of podocyte genes. Full delineation of the LMX1B gene regulon is needed to define its role in maintenance of glomerular filtration barrier integrity.
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