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Gholami Yarahmadi S, Sarlaki F, Morovvati S. Cystinosis and two rare mutations in CTNS gene: two case reports. J Med Case Rep 2022; 16:181. [PMID: 35513889 PMCID: PMC9074344 DOI: 10.1186/s13256-022-03379-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 03/18/2022] [Indexed: 11/22/2022] Open
Abstract
Background Cystinosis is an autosomal recessive disorder characterized by an accumulation of the amino acid cystine in lysosomes throughout the body. Cystinosis is an inherited disease resulting from the failure of lysosomal cystine transport. The responsible gene, Cystinosin, Lysosomal Cystine Transporter (CTNS), encodes the lysosomal cystine carrier cystinosin. Case presentation In this case report, we reviewed the genetic basis of cystinosis and investigated two Iranian cases affected by cystinosis, one of which revealed a rare mutation in the CTNS gene. Two patients, 9-year-old (patient A) and 11-year-old (patient B) symptomatic Iranian females with renal insufficiency, were diagnosed with cystinosis on the basis of their clinical features and laboratory tests. After genetic counseling, blood samples were obtained from the patients and their parents. Genomic Deoxyribonucleic Acid (DNA) was extracted from whole blood, and mutation analysis was performed using polymerase chain reaction and sequencing methods for all exons of the CTNS gene. At least 148 different pathogenic and deleterious mutations in the CTNS gene have been reported to date. Owing to our patient’s prominent clinical features of cystinosis, we carried out a targeted search for mutations in the CTNS gene. Conclusions This led us to confirm the existence of a homozygous DNA variation c.257_258deletionCT (p.Ser86PhefsTer38) in exon 6 of the gene in patient A and another homozygous DNA variation, c.323delA (p.Q108RfsTer10), in the same exon in patient B. As expected, the mentioned mutation existed in both her parents in a heterozygous state. Variations c.257_258delCT and c.323delA reported in three Iranian patients in the CTNS gene are frameshifts, and truncating mutations that affect product function result in relatively mild symptoms of cystinosis. The present finding confirms previous research and proves the importance of the association of this gene rare mutations with cystinosis. Since reported mutations are rare, their previous reports in Iranian patients indicate the high frequency of these mutations in our region.
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Affiliation(s)
- Sepideh Gholami Yarahmadi
- Department of Advanced Sciences and Technology, Islamic Azad University-Tehran Medical Sciences, Zargandeh, Shariati, Tehran, Iran
| | - Fatemeh Sarlaki
- Department of Clinical Biochemistry, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Saeid Morovvati
- Department of Advanced Sciences and Technology, Islamic Azad University-Tehran Medical Sciences, Zargandeh, Shariati, Tehran, Iran.
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Klootwijk E, Dufek S, Issler N, Bockenhauer D, Kleta R. Pathophysiology, current treatments and future targets in hereditary forms of renal Fanconi syndrome. Expert Opin Orphan Drugs 2016. [DOI: 10.1080/21678707.2017.1259560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
| | - Stephanie Dufek
- Centre for Nephrology, University College London, London, UK
| | - Naomi Issler
- Centre for Nephrology, University College London, London, UK
| | | | - Robert Kleta
- Centre for Nephrology, University College London, London, UK
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Klootwijk ED, Reichold M, Helip-Wooley A, Tolaymat A, Broeker C, Robinette SL, Reinders J, Peindl D, Renner K, Eberhart K, Assmann N, Oefner PJ, Dettmer K, Sterner C, Schroeder J, Zorger N, Witzgall R, Reinhold SW, Stanescu HC, Bockenhauer D, Jaureguiberry G, Courtneidge H, Hall AM, Wijeyesekera AD, Holmes E, Nicholson JK, O'Brien K, Bernardini I, Krasnewich DM, Arcos-Burgos M, Izumi Y, Nonoguchi H, Jia Y, Reddy JK, Ilyas M, Unwin RJ, Gahl WA, Warth R, Kleta R. Mistargeting of peroxisomal EHHADH and inherited renal Fanconi's syndrome. N Engl J Med 2014; 370:129-38. [PMID: 24401050 DOI: 10.1056/nejmoa1307581] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND In renal Fanconi's syndrome, dysfunction in proximal tubular cells leads to renal losses of water, electrolytes, and low-molecular-weight nutrients. For most types of isolated Fanconi's syndrome, the genetic cause and underlying defect remain unknown. METHODS We clinically and genetically characterized members of a five-generation black family with isolated autosomal dominant Fanconi's syndrome. We performed genomewide linkage analysis, gene sequencing, biochemical and cell-biologic investigations of renal proximal tubular cells, studies in knockout mice, and functional evaluations of mitochondria. Urine was studied with the use of proton nuclear magnetic resonance ((1)H-NMR) spectroscopy. RESULTS We linked the phenotype of this family's Fanconi's syndrome to a single locus on chromosome 3q27, where a heterozygous missense mutation in EHHADH segregated with the disease. The p.E3K mutation created a new mitochondrial targeting motif in the N-terminal portion of EHHADH, an enzyme that is involved in peroxisomal oxidation of fatty acids and is expressed in the proximal tubule. Immunocytofluorescence studies showed mistargeting of the mutant EHHADH to mitochondria. Studies of proximal tubular cells revealed impaired mitochondrial oxidative phosphorylation and defects in the transport of fluids and a glucose analogue across the epithelium. (1)H-NMR spectroscopy showed elevated levels of mitochondrial metabolites in urine from affected family members. Ehhadh knockout mice showed no abnormalities in renal tubular cells, a finding that indicates a dominant negative nature of the mutation rather than haploinsufficiency. CONCLUSIONS Mistargeting of peroxisomal EHHADH disrupts mitochondrial metabolism and leads to renal Fanconi's syndrome; this indicates a central role of mitochondria in proximal tubular function. The dominant negative effect of the mistargeted protein adds to the spectrum of monogenic mechanisms of Fanconi's syndrome. (Funded by the European Commission Seventh Framework Programme and others.).
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Affiliation(s)
- Enriko D Klootwijk
- From the Centre for Nephrology (E.D.K., H.C.S., D.B., G.J., H.C., A.M.H., R.J.U., R.K.) and Institute of Child Health (D.B., R.K.), University College London, and Biomolecular Medicine, Imperial College London (S.L.R., A.D.W., E.H., J.K.N.) - both in London; the Departments of Medical Cell Biology (M.R., C.B., D.P., C.S., R. Warth), Internal Medicine III (K.R.), Internal Medicine II (S.W.R.), and Molecular and Cellular Anatomy (R. Witzgall) and the Institutes of Functional Genomics (J.R., K.E., N.A., P.J.O., K.D.) and Pathology (J.S.), University of Regensburg, and the Department of Radiology, Barmherzige Brueder Hospital (N.Z.) - all in Regensburg, Germany; the National Human Genome Research Institute (A.H.-W., S.L.R., H.C.S., K.O., I.B., D.M.K., W.A.G., R.K.) and National Heart, Lung, and Blood Institute (Y.I.), National Institutes of Health, Bethesda, MD; the Division of Pediatric Nephrology, University of Florida, Jacksonville (A.T., M.I.); the Genome Biology Department, Australian National University, Canberra, ACT, Australia (M.A.-B.); Kitasato University Medical Center, Saitama, Japan (H.N.); and the Department of Pathology, Northwestern University, Chicago (Y.J., J.K.R.)
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Nesterova G, Gahl WA. Cystinosis: the evolution of a treatable disease. Pediatr Nephrol 2013; 28:51-9. [PMID: 22903658 PMCID: PMC3505515 DOI: 10.1007/s00467-012-2242-5] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 06/07/2012] [Accepted: 06/08/2012] [Indexed: 11/01/2022]
Abstract
Cystinosis is a rare autosomal recessive disorder involving lysosomal storage of the amino acid cystine due to a defect in the membrane transport protein, cystinosin. Since the introduction of kidney transplants and the availability of cystine-depleting medical therapy, this previously fatal disease was transformed into a treatable disorder. Renal allografts and medical therapy targeting the basic metabolic defect have altered the natural hisotry of cystinosis so drastically that patients have a life expectancy extending past 50 years. Consequently, early diagnosis and appropriate therapy are critically important. In this article, we offer a review of the manifestations of cystinosis, including the proximal tubular dysfunction of renal Fanconi syndrome, and discuss the prevention and treatment of the disorder's systemic complications. We focus on the nephropathic forms of cystinosis, aiming to assist nephrologists and other physicians to develop early recognition and appropriate management of cystinosis patients.
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Affiliation(s)
- Galina Nesterova
- NHGRI, Medical Biochemical Genetic Section, National Institutes of Health, Bethesda, MD, USA.
| | - William A. Gahl
- NHGRI, Medical Biochemical Genetic Section, National Institutes of Health, Bethesda, MD USA
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Nesterova G, Gahl W. Nephropathic cystinosis: late complications of a multisystemic disease. Pediatr Nephrol 2008; 23:863-78. [PMID: 18008091 DOI: 10.1007/s00467-007-0650-8] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Revised: 09/24/2007] [Accepted: 09/24/2007] [Indexed: 11/29/2022]
Abstract
Cystinosis is a rare autosomal recessive disorder due to impaired transport of cystine out of cellular lysosomes. Its estimated incidence is 1 in 100,000 live births. End-stage renal disease (ESRD) is the most prominent feature of cystinosis and, along with dehydration and electrolyte imbalance due to renal tubular Fanconi syndrome, has accounted for the bulk of deaths from this disorder. Prior to renal transplantation and cystine-depleting therapy with cysteamine for children with nephropathic cystinosis, their lifespan was approximately 10 years. Now, cystinotic patients have survived through their fifth decade, but the unremitting accumulation of cystine has created significant non-renal morbidity and mortality. In this article we review the classic presentation of nephropathic cystinosis and the natural history, diagnosis, and treatment of the disorder's systemic involvement. We also emphasize the role of oral cysteamine therapy in preventing the late complications of cystinosis.
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Affiliation(s)
- Galina Nesterova
- Section on Human Biochemical Genetics, Human Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892-1851, USA
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Emadi A, Burns KH, Confer B, Borowitz MJ, Streiff MB. Hematological manifestations of nephropathic cystinosis. Acta Haematol 2008; 119:169-72. [PMID: 18493119 DOI: 10.1159/000134222] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2008] [Accepted: 03/10/2008] [Indexed: 11/19/2022]
Abstract
Pancytopenia is an uncommon manifestation of cystinosis, a congenital lysosomal storage disease. We describe a 34-year-old patient with nephropathic cystinosis with multisystem involvement who developed progressive bone marrow failure after renal transplantation. Bone marrow examination demonstrated widespread deposition of cystine crystals in histiocytes and in the background. We review the literature on the hematologic manifestations of cystinosis and discuss the available treatment options for patients with bone marrow failure secondary to cystine accumulation. The availability of effective oral therapy and the limited activity of hematopoietic growth factors in these patients highlight the importance of bone marrow examination early in the evaluation of cystinosis patients with abnormal blood counts.
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Affiliation(s)
- Ashkan Emadi
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD 21231-1000, USA.
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Kessler A, Biasibetti M, da Silva Melo DA, Wajner M, Dutra-Filho CS, de Souza Wyse ÂT, Wannmacher CMD. Antioxidant Effect of Cysteamine in Brain Cortex of Young Rats. Neurochem Res 2007; 33:737-44. [DOI: 10.1007/s11064-007-9486-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Accepted: 08/21/2007] [Indexed: 10/22/2022]
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Kleta R, Gahl WA. Pharmacological treatment of nephropathic cystinosis with cysteamine. Expert Opin Pharmacother 2004; 5:2255-62. [PMID: 15500372 DOI: 10.1517/14656566.5.11.2255] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Cystinosis, clinically recognised since 1903, is an autosomal recessive lysosomal storage disease caused by mutations in CTNS. This gene codes for a lysosomal cystine transporter, whose absence leads to intracellular cystine crystals, widespread cellular destruction, renal Fanconi syndrome in infancy, renal glomerular failure in later childhood and other systemic complications. Before the availability of kidney transplantation, patients affected with cystinosis uniformly died during childhood. After solid organ transplantations became successful in the 1960s, cystinosis patients survived, but eventually developed life-threatening consequences of the disease (e.g., swallowing disorders). Since the introduction of cysteamine into the pharmacological management of cystinosis, well-treated adolescent and young adult patients have experienced normal growth and maintenance of renal glomerular function. Oral cysteamine therapy is given at doses of 60 - 90 mg/kg/day q.i.d. every 6 h, and generally achieves approximately 90% depletion of cellular cystine, as measured in circulating leucocytes. Cysteamine (and kidney transplantation) have commuted the death sentence of cystinosis into a nearly normal life with a chronic disease. Because treatment with oral cysteamine can prevent, or significantly delay, the complications of cystinosis, early and accurate diagnosis, as well as proper treatment, is critical.
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Affiliation(s)
- Robert Kleta
- NHGRI, Building 10, Room 10C-107, MSC 1851, 10 Center Drive, Bethesda, MD 20892, USA.
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Abstract
We report the excellent clinical outcomes of siblings with nephropathic cystinosis treated diligently with cysteamine starting at 20 months and 2 months of age. Now 15 and 8 years old, they have glomerular filtration rates of 78 and 105 mL/min/1.73m 2 , respectively. These cases illustrate the critical importance of early diagnosis and treatment.
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