1
|
|
2
|
Goyenechea E, Andrade F, de Las Heras J, Lage S, Prieto JÁ, Ruiz N, Aldámiz-Echevarría L. Expression of proinflammatory factors in renal cortex induced by methylmalonic acid. Ren Fail 2012; 34:885-91. [PMID: 22583396 DOI: 10.3109/0886022x.2012.684554] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Methylmalonic aciduria is an inborn error of metabolism that causes renal failure and tubulointerstitial (TI) nephritis as complications. This study aimed to examine the levels of expression of several genes related to inflammation, oxidative stress, and mitochondrial function in the renal cortex of rats receiving methylmalonic acid (MMA). METHODS Rats received MMA subcutaneously for a month. Tumor necrosis factor alpha (TNFα), nuclear factor-kappa B, interleukin 1 beta (IL-1β), and cyclooxygenase 2 (COX-2) genes were examined by real-time polymerase chain reaction. We also examined transforming growth factor beta (TGF-β) related to TI fibrosis, c-FOS, belonging to the immediate early gene family of transcription factors, and expression of SIRT1, related to energy production. RESULTS There was significantly higher expression of TNFα and a trend toward a higher level of TGF-β transcripts in the methylmalonic model group compared with the controls. However, SIRT1 expression was not different among the groups. Urinary MMA excretion correlated positively with mRNA level of TGF-β. The expression of COX-2 was positively associated with the expression of c-FOS and inversely related to the expression of IL-1β. CONCLUSIONS The higher levels of TNFα and TGF-β transcripts suggest inflammation and differentiation processes in the renal cortex in rats because of MMA. After 1 month of MMA injections, expression levels of SIRT1 were not affected, suggesting mitochondrial preservation in early stages of the disease.
Collapse
|
3
|
Menegon LF, Amaral TN, Gontijo JAR. Renal Sodium Handling Study in an Atypical Case of Bartter's Syndrome Associated with Mitochondriopathy and Sensorineural Blindness. Ren Fail 2009; 26:195-7. [PMID: 15287206 DOI: 10.1081/jdi-120038522] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Bartter's syndrome is a disorder that has been linked to mutations in one of three ion transporter proteins: NKCC2 (type I), ROMK (type II) and CCLNKB (type III), which affects a final common pathway that participates in ion transport by thick ascending limb cells. We present an atypical case of mitochondriopathy combined with tubule functional disturbances compatible with Bartter's syndrome and definitive sensorineural blindness. Our patient had a peculiar clinical presentation with signs of salt and volume depletion, low blood pressure and secondary hyperaldosteronism, associated with hypokalemic metabolic alkalosis, hypocalcemia and severe hypomagnesemia, uncommon in genetic forms of Bartter's syndrome. The enhanced absolute and fractional sodium excretion in our patient compared to volunteers was accompanied by increased post-proximal sodium rejection, suggesting a striking ion transport dysfunction in these nephron segments. These findings lead to the Bartter's syndrome diagnosis, accompanied by a suppose mitochondrial tick ascending loop of Henle epithelium dysfunction that may reflect the high energy supplied by mitochondria electron transport chain, required for this nephron segment to maintain normal ion transport.
Collapse
Affiliation(s)
- L F Menegon
- Disciplina de Medicina Interna, Laboratório Balanço Hidro-Salino, Núcleo de Medicina e Cirurgia Experimental, Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, Sao Paulo, Brazil
| | | | | |
Collapse
|
4
|
Yuri T, Kondo Y, Kohno K, Lei YC, Kanematsu S, Kuwata M, Iwasaka T, Tsubura A. An autopsy case of chronic progressive external ophthalmoplegia with renal insufficiency. Med Mol Morphol 2008; 41:233-7. [PMID: 19107614 DOI: 10.1007/s00795-008-0420-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Accepted: 09/17/2008] [Indexed: 01/08/2023]
Abstract
An autopsy of a 44-year-old Japanese woman with mitochondrial cytopathy confirmed the presence of chronic progressive external ophthalmoplegia (CPEO). Immunohistochemistry using antimitochondrial antibody was performed to observe the ultrastructure of the skeletal muscle and renal tissues. The patient was born of consanguineous parents, developed normally, and was of average intelligence. At 22 years of age, the patient noticed hearing loss, and subsequently, over time, developed a progressive generalized muscle weakness, which included limitation of eye movement and ptosis. At age 41, a muscle biopsy was performed using the modified Gomori trichrome method and demonstrated the presence of ragged red fibers. After the evaluation of her results in conjunction with her clinical course, she was diagnosed with CPEO. Renal insufficiency was discovered at age 30, and the patient died at the age of 44 of respiratory failure caused by respiratory muscle weakness and pneumonia. The autopsy revealed fiber size variation within the skeletal muscle, and an antimitochondrial antibody analysis demonstrated the accumulation of mitochondria between the bundles of myofibrils, as well as in subsarcolemmal locations. Ultrastructurally, abnormal mitochondria with disoriented cristae and paracrystalline inclusions were seen. Although no remarkable histological changes were noted in the kidneys, tubular epithelial cells exhibited accumulated abnormal mitochondria, similar to those seen in the skeletal muscle. Because mitochondrial diseases can affect other energy-dependent organs in addition to the skeletal muscle, immunohistochemical examinations employing an antimitochondrial antibody are useful for obtaining further ultrastructural observations that can assist in making a distinct diagnosis of this systemic disorder.
Collapse
Affiliation(s)
- Takashi Yuri
- Department of Pathology II, Kansai Medical University, Moriguchi, Osaka, 570-8506, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
5
|
Lubrano R, Elli M, Rossi M, Travasso E, Raggi C, Barsotti P, Carducci C, Berloco P. Renal transplant in methylmalonic acidemia: could it be the best option? Report on a case at 10 years and review of the literature. Pediatr Nephrol 2007; 22:1209-14. [PMID: 17401587 DOI: 10.1007/s00467-007-0460-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2006] [Revised: 01/28/2007] [Accepted: 01/30/2007] [Indexed: 12/16/2022]
Abstract
Methylmalonic acidemia (MMA) is an inborn error of organic acid metabolism. Patients with severe disease develop many complications despite treatment; often, the disease progresses to severe damage of the central nervous system or to end-stage renal disease (ESRD). When medical treatment is ineffective, liver, kidney, or combined liver and kidney transplantation is advocated. At present, there are no definite guidelines as for the organ to be transplanted, and results are inconsistent. We report on a 27-year-old woman with MMA MUT0. The clinical symptoms developed at age 4 months. She progressed to ESRD and received a kidney transplant in November 1996 at age 17 years. One hundred and twenty months after transplant, renal function is normal; although urinary levels of methylmalonic acid are above normal limits, no episodes of metabolic decompensation have been observed after transplantation. Although liver is the major site of methylmalonyl-CoA mutase activity, this case and similar ones in the literature suggest that the smaller mutase activity present in the transplanted kidney may be sufficient to ensure partial correction of the metabolism of organic acids sufficient to prevent the onset of episodes of metabolic decompensation. It is worth investigating whether kidney transplant can be a safer and more satisfactory alternative to liver transplantation in cases of MMA unresponsive to medical treatment although urine MMA excretion remains significantly elevated.
Collapse
Affiliation(s)
- Riccardo Lubrano
- Dipartimento di Pediatria, Università degli Studi di Roma La Sapienza, Viale Regina Elena 324, 00161, Rome, Italy.
| | | | | | | | | | | | | | | |
Collapse
|
6
|
Oldfors A, Tulinius M. Mitochondrial encephalomyopathies. HANDBOOK OF CLINICAL NEUROLOGY 2007; 86:125-165. [PMID: 18808998 DOI: 10.1016/s0072-9752(07)86006-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
|
7
|
Bockenhauer D, Rees L, van't Hoff W. An association of tubular dysfunction, cortical macrocysts and chronic kidney disease. Pediatr Nephrol 2006; 21:580-3. [PMID: 16508772 DOI: 10.1007/s00467-006-0009-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2005] [Revised: 09/23/2005] [Accepted: 10/07/2005] [Indexed: 10/25/2022]
Abstract
We present an unusual combination of kidney disorders in a boy born to consanguineous parents. He presented in the first year of life with dehydration and urosepsis and was subsequently found to have hyposthenuria and distal renal tubular acidosis, with normal appearance of the kidneys, by ultrasound examination. By 4 years of age he had developed multiple large cysts in both kidneys, and his nephropathy eventually progressed so that at 17 years of age he is approaching end-stage renal disease (ESRD). The association of initial tubular dysfunction followed by the development of multiple cysts may represent a new form of kidney disease.
Collapse
Affiliation(s)
- Detlef Bockenhauer
- Paediatric Nephrology, Great Ormond Street Hospital, Great Ormond Street, London, WC1 3JH, UK.
| | | | | |
Collapse
|
8
|
López S, Negredo E, Garrabou G, Puig J, Ruiz L, Sanjurjo E, Ramos X, Infante AB, Casademont J, Cardellach F, Clotet B, Miró O. Longitudinal study on mitochondrial effects of didanosine-tenofovir combination. AIDS Res Hum Retroviruses 2006; 22:33-9. [PMID: 16438643 DOI: 10.1089/aid.2006.22.33] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Tenofovir disoproxil fumarate (TDF) has been reported to be free of adverse effects on mitochondria. We evaluate the effects of the introduction of TDF in a didanosine (ddI)-based highly active antiretroviral therapy (HAART) on mitochondrial DNA (mtDNA) content, mitochondrial mass (MM), and cytochrome c oxidase (COX) activity of the oxidative phosphorylation (OXPHOS) system over a 12-month period. Forty-four asymptomatic HIV patients with undetectable viral load receiving a ddI-based HAART were recruited and switched to ddI plus TDF (ddI + TDF) and nevirapine (n = 22) or maintained with the same baseline ddIbased HAART scheme (n = 22). Peripheral blood mononuclear cells were obtained at 0, 6, and 12 months. COX activity and MM were determined by spectrophotometry and the mtDNA content by quantitative realtime PCR. The mtDNA content showed a progressive decrease over the 12-month period of the study for the two groups with respect to baseline, with such a decrease statistically significant only in the ddI + TDF group (55% decrease, p < 0.001). In addition, the decrease of mtDNA content over time was statistically different between both groups (p < 0.001). Consistently, MM and COX activity decreased significantly at 12 months with respect to baseline only in the ddI < TDF group (28% decrease for MM, p < 0.05; 47% decrease for COX activity, p < 0.001). We conclude that switching to a HAART regimen containing ddI + TDF is associated with evolutive mitochondrial damage expressed as mtDNA depletion, loss of MM, and decrease in COX efficiency. The particular relevance of either ddI, TDF, or any interaction between them in such a mitochondrial dysfunction remains to be established.
Collapse
Affiliation(s)
- Sònia López
- Mitochondrial Research Laboratory, Muscle Research Unit, Internal Medicine Department, Hospital Clínic of Barcelona, IDIBAPS, University of Barcelona, Barcelona, Catalonia, Spain
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Güçer S, Talim B, Aşan E, Korkusuz P, Ozen S, Unal S, Kalkanoğlu SH, Kale G, Cağlar M. Focal segmental glomerulosclerosis associated with mitochondrial cytopathy: report of two cases with special emphasis on podocytes. Pediatr Dev Pathol 2005; 8:710-7. [PMID: 16328667 DOI: 10.1007/s10024-005-0058-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2005] [Accepted: 07/28/2005] [Indexed: 10/25/2022]
Abstract
We report two children with focal segmental glomerulosclerosis (FSGS) associated with mitochondrial cytopathy (MC). Case 1 was diagnosed as MC with the findings of ptosis, ophthalmoplegia, failure to thrive, high serum lactate and pyruvate levels, ragged red fibers in muscle biopsy and the common 4.9 kb deletion in mtDNA when she was four years old. She subsequently developed FSGS four years later. Case 2 was a four month-old girl presenting with feeding difficulty from birth, with vomiting, seizures and nystagmoid eye movements, nephrotic proteinuria and hematuria. Renal biopsy revealed FSGS. Ultrastructural study demonstrated markedly pleomorphic mitochondria in podocytes with a severe effacement of foot processes. The analyses of muscle biopsy and skin fibroblasts for respiratory chain enzymes were found to be normal, while mitochondrial DNA analysis revealed the population of a single deleted mtDNA in the heteroplasmic state. The present cases illustrate FSGS as a rare renal complication of mitochondrial disease and provide further evidence of podocytes possessing abnormal mitochondria which may cause glomerular epithelial cell damage leading to glomerulosclerosis.
Collapse
Affiliation(s)
- Safak Güçer
- Department of Pediatrics, Pathology Unit, Hacettepe University Faculty of Medicine, Ankara 06100, Turkey.
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Unal S, Kalkanoğlu HS, Kocaefe C, Gucer S, Ozen S, Turanli G, Coskun T. Four-month-old infant with focal segmental glomerulosclerosis and mitochondrial DNA deletion. J Child Neurol 2005; 20:83-4. [PMID: 15791930 DOI: 10.1177/08830738050200011304] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mitochondrial cytopathies are a group of heterogeneous disorders characterized by multisystem involvement. Renal involvement in mitochondrial cytopathies is usually manifested as tubular dysfunction owing to impaired energy metabolism; however, a few cases with glomerular changes have also been reported. Herein we report the case of a 4-month-old Turkish girl with a mitochondrial DNA deletion and focal segmental glomerulosclerosis.
Collapse
Affiliation(s)
- Sule Unal
- Department of Pediatrics, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | | | | | | | | | | | | |
Collapse
|
11
|
Hörster F, Hoffmann GF. Pathophysiology, diagnosis, and treatment of methylmalonic aciduria-recent advances and new challenges. Pediatr Nephrol 2004; 19:1071-4. [PMID: 15293040 DOI: 10.1007/s00467-004-1572-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2004] [Accepted: 05/18/2004] [Indexed: 12/31/2022]
Abstract
Classical methylmalonic aciduria is a relatively rare inborn error of branched-chain amino acid metabolism, occurring in 1:50,000 to 1:80,000 newborns. Three decades after its recognition, major progress has been made in survival and prevention of neurological sequelae in affected children, if the diagnosis is made early and treatment and follow-up care are meticulous. Therapy consists of a specially formulated protein diet, carnitine supplementation, and vigorous emergency treatment during intercurrent illnesses aimed at preventing the development of catabolism. Recently the clinician has been challenged by partially unexpected long-term complications. These include chronic neurological symptoms, specifically an extrapyramidal movement disorder caused by progressive destruction of the basal ganglia, which are similar to those observed in other organic acid disorders, such as propionic aciduria or glutaric aciduria type I. Unexpected and unique is the development of chronic renal failure in a major subset of patients. As the pathophysiological basis of renal failure is still obscure, no causative treatment is available and hemodialysis may become necessary. Experience with transplantation of liver, kidney, or kidney and liver is very limited and allows as yet no conclusions. Interdisciplinary research efforts in this field should reveal new pathophysiological links and hopefully provide additional therapeutic approaches.
Collapse
|
12
|
Scaglia F, Vogel H, Hawkins EP, Vladutiu GD, Liu LL, Wong LJC. Novel homoplasmic mutation in the mitochondrialtRNATyr gene associated with atypical mitochondrial cytopathy presenting with focal segmental glomerulosclerosis. ACTA ACUST UNITED AC 2003; 123A:172-8. [PMID: 14598342 DOI: 10.1002/ajmg.a.20315] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We report a 9-year-old girl with a mitochondrial cytopathy preceded by steroid-resistant focal segmental glomerulosclerosis (FSGS). The proband presented at the age of 2 years with steroid-resistant nephrotic syndrome caused by FSGS. Her renal function progressively deteriorated and a dilated cardiomyopathy developed at the age of 7 years. A skeletal muscle biopsy showed a combined respiratory chain (RC) defect and a partial deficiency of coenzyme Q(10). A novel mutation in the evolutionary highly conserved region of the mitochondrial tRNA(Tyr) gene was found in homoplasmic state in skeletal muscle, blood, and renal tissue. The mutation was also found in homoplasmic state in her mildly symptomatic mother. No other maternal family members were available for testing. The present case of mitochondrial cytopathy initially presenting with steroid-resistant nephrotic syndrome, unusual biochemical and renal findings associated with a novel tRNA point mutation suggests that steroid-resistant FSGS can predate other features of mitochondrial disease for a prolonged period of time and that the progressive glomerulopathy associated with combined mitochondrial RC defects is genetically heterogeneous.
Collapse
MESH Headings
- Abnormalities, Multiple/genetics
- Base Sequence
- Biopsy
- Child
- Child, Preschool
- Chromatography, High Pressure Liquid
- Coenzymes
- DNA, Mitochondrial/genetics
- Female
- Glomerulosclerosis, Focal Segmental/genetics
- Glomerulosclerosis, Focal Segmental/pathology
- Humans
- Immunohistochemistry
- Kidney/ultrastructure
- Microscopy, Electron
- Mitochondrial Diseases/genetics
- Molecular Sequence Data
- Muscle, Skeletal/ultrastructure
- Mutation/genetics
- RNA, Transfer/genetics
- Sequence Alignment
- Sequence Analysis, DNA
- Tyrosine
- Ubiquinone/analogs & derivatives
- Ubiquinone/genetics
Collapse
Affiliation(s)
- Fernando Scaglia
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, USA.
| | | | | | | | | | | |
Collapse
|
13
|
McDonald DGM, McMenamin JB, Farrell MA, Droogan O, Green AJ. Familial childhood onset neuropathy and cirrhosis with the 4977bp mitochondrial DNA deletion. AMERICAN JOURNAL OF MEDICAL GENETICS 2002; 111:191-4. [PMID: 12210349 DOI: 10.1002/ajmg.10522] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The common 4977 base pair mitochondrial deletion has been identified in association with a number of distinct clinical phenotypes. These include the Kearns-Sayre syndrome, the Pearson marrow-pancreas syndrome, and chronic progressive external ophthalmoplegia. We report the clinical and pathological findings in two siblings in whom the 4977 base pair mitochondrial DNA deletion was identified in muscle-derived mitochondrial DNA. One sibling manifested early onset liver and renal failure, and both developed prominent peripheral sensorimotor neuropathy. These clinical findings have not been previously described in association with the 4977bp mtDNA deletion and thus represent a further expansion of the spectrum of mitochondrial disease.
Collapse
Affiliation(s)
- D G M McDonald
- Department of Neurology, Our Lady's Hospital for Sick Children, Crumlin, Dublin, Ireland
| | | | | | | | | |
Collapse
|
14
|
Maassen JA. Mitochondrial diabetes: pathophysiology, clinical presentation, and genetic analysis. AMERICAN JOURNAL OF MEDICAL GENETICS 2002; 115:66-70. [PMID: 12116179 DOI: 10.1002/ajmg.10346] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
This study provides a compact overview on the most common form of the maternally inherited diabetes and deafness syndrome (MIDD) that associates with an A-G mutation in mitochondrial DNA at position 3243 in the tRNA(Leu,UUR) gene. The pathobiochemistry and pathophysiology is discussed. The mutation leads predominantly to a reduced insulin secretion by beta cells in response to glucose stimulation, however, without marked involvement of autoimmune processes as seen in type 1 diabetes mellitus. The underlying biochemical mechanism leading to beta cell dysfunction is discussed. Furthermore, the clinical presentation of the disease is summarized as are the methods to detect the A3243G mutation, particular in view of the often low levels of heteroplasm of the A3243G mutation.
Collapse
Affiliation(s)
- J Antonie Maassen
- Department of Molecular Cell Biology, LUMC, Leiden, The Netherlands.
| |
Collapse
|
15
|
Abstract
This review discusses the current insight by which mutations in mitochondrial DNA (mtDNA) contribute to the development of particular disease states with emphasis on diabetes mellitus. Mitochondria are the power factories of the cells and produce ATP by oxidizing reducing equivalents via the respiratory chain. These reducing equivalents originate mainly from the citric acid cycle that also occurs within the mitochondria. Human mitochondria contain their own genetic material in the form of circular DNA that encodes for only a fraction of the mitochondrial components. The other mitochondrial components are nuclear encoded. Pathogenic mutations in mtDNA can affect the activity of the respiratory chain, thereby leading to the reduced generation of ATP. However, mitochondria not only produce ATP but they also regulate cytosolic concentrations of signaling molecules such as calcium and iron ions. The metabolic processes within mitochondria such as the citric acid cycle determine the concentration of metabolites that can also act as signalling molecules. Furthermore, the respiratory chain and mitochondrion-associated monoamine oxidase are major producers of reactive oxygen radicals. As a result, mutations in mtDNA can deregulate multiple processes within cells and the balance of this deregulation may contribute to the clinical phenotype.
Collapse
Affiliation(s)
- J A Maassen
- Department of Molecular Cell Biology, Leiden University Medical Center, The Netherlands.
| | | | | |
Collapse
|
16
|
Tzen CY, Tsai JD, Wu TY, Chen BF, Chen ML, Lin SP, Chen SC. Tubulointerstitial nephritis associated with a novel mitochondrial point mutation. Kidney Int 2001; 59:846-54. [PMID: 11231339 DOI: 10.1046/j.1523-1755.2001.059003846.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Nephropathy caused by mitochondrial disorders is a relatively newly recognized disease. Only a few cases have been reported in the literature, and most of them are proximal tubulopathy-presenting Fanconi syndrome. Here we report on a novel mutation in two familial cases of tubulointerstitial nephropathy associated with concentrating defect. METHODS Renal biopsy specimens were examined by light microscopy and electron microscopy. Mitochondrial genomic DNA isolated from renal biopsy specimens was amplified by polymerase chain reaction (PCR) and sequenced in its entirety. The DNA sequences were analyzed by (1) comparing with the Anderson et al's mitochondrial sequences; (2) comparing with DNA sequences obtained from 97 human controls, including both healthy individuals and patients with renal diseases; and (3) comparing with the counterparts in 90 different species. RESULTS Dismorphic mitochondria with occasional intramitochondrial inclusions were found in the renal tubular epithelial cells. A novel mitochondrial point mutation was identified at the position 608, that is, the distal end of the anticodon stem of the tRNA(Phe) molecule. The A to G substitution at this position was not observed in 97 human controls and was found to be highly conserved in evolution. CONCLUSIONS We have identified an A608G mutation of mitochondrial genome in two cases whose presentation include tubulointerstitial nephritis and stroke.
Collapse
Affiliation(s)
- C Y Tzen
- Department of Pathology, Mackay Memorial Hospital, Taipei, Taiwan.
| | | | | | | | | | | | | |
Collapse
|
17
|
Abstract
Severe muscle weakness in Fanconi's syndrome is rarely the result of mitochondrial cytopathy. We describe a rare case of a 9-year-old male with early onset of Fanconi's syndrome. He developed severe proximal muscle weakness exacerbated by hypokalemia and hypophosphatemia in childhood. The muscle biopsy revealed increased accumulation of abnormal mitochondria and fat droplets in histochemical stains and electron microscopy. Mitochondrial cytopathy cannot be excluded in Fanconi's syndrome with late onset of muscular impairment. Long-term follow-up of his clinical course is suggested to understand the natural history of this unusual case.
Collapse
Affiliation(s)
- L C Wang
- Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
| | | | | | | | | |
Collapse
|