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Bako D, Kılavuz S, Yasin Köksoy A, Uzan Tatli Z, Beydogan E. A different approach to cystinosis: ultrasound, doppler, and shear wave elastography findings of thyroid gland. Orphanet J Rare Dis 2023; 18:173. [PMID: 37391835 DOI: 10.1186/s13023-023-02783-6] [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: 02/26/2023] [Accepted: 06/18/2023] [Indexed: 07/02/2023] Open
Abstract
BACKGROUND While thyroid dysfunction develops in about 50% of untreated children with cystinosis, there is no data about how the sonography of thyroid tissue appears in this disease. Therefore, the purpose of this study was to assess the sonographic appearance, color doppler findings in this disease and to evaluate how cystine crystal accumulation affect tissue stiffness using shear wave elastography (SWE). METHODS Sixteen children diagnosed with cystinosis and a control group consisting of 34 healthy children were included in this study. B mode ultrasound, color doppler imaging and real-time SWE of thyroid tissue were performed. RESULTS Ultrasound imaging revealed lower echogenicity and diffuse heterogeneous echotexture in 7 of the 16 cystinosis patients. Thyroid gland volumes were lower in cystinosis patients (p 0.005). Doppler ultrasound demonstrated increased flow in 8 patients. On SWE, the thyroid tissue stiffness was established to be lower in patients compared to healthy children (p 0.003). CONCLUSIONS This is the first study evaluating thyroid gland B mode, color doppler ultrasonography, and SWE findings in cystinosis. Our findings indicate that cysteamine treatment still cannot completely prevent the disease infiltration process of thyroid gland. The other important finding-that thyroid tissue stiffness was established to be lower than that of the controls-also demonstrates the ongoing disease infiltration process.
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Affiliation(s)
- Derya Bako
- Department of Pediatric Radiology, Van Regional Training and Research Hospital, Van, Turkey.
| | - Sebile Kılavuz
- Department of Pediatric Pediatric Metabolism and Nutrition, Van Regional Training and Research Hospital, Van, Turkey
| | - Adem Yasin Köksoy
- Department of Pediatric Pediatric Nephrology, Van Regional Training and Research Hospital, Van, Turkey
| | - Zeynep Uzan Tatli
- Department of Pediatric Pediatric Endocrinology, Zeynep Uzan Tatli, Van Regional Training and Research Hospital, Van, Turkey
| | - Engin Beydogan
- Department of Radiology, Van Regional Training and Research Hospital, Van, Turkey
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Keidel LF, Schworm B, Hohenfellner K, Kruse F, Priglinger S, Luft N, Priglinger C. Posterior Segment Involvement in Infantile Nephropathic Cystinosis - A Review. Klin Monbl Augenheilkd 2023; 240:266-275. [PMID: 36977427 DOI: 10.1055/s-0037-1599653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
Cystinosis is a rare lysosomal storage disease with a prevalence of 1 : 100 000 - 1 : 200 000 cases. It is caused by biallelic mutations in the CTNS gene, which encodes cystinosin, that transport cystine out of the lysosomes. Due to its dysfunction, cystine crystals accumulate in the lysosomes and ultimately cause apoptosis of the cell. Since cystinosin is ubiquitously present in the body, cystine crystals are deposited in every body structure and lead to the dysfunction of various organ systems in the course of time. Cystine crystals deposited in the cornea are a clinical hallmark of the disease, while there is less awareness of concomitant posterior segment alterations. Symmetrical pigment epithelial mottling and patches of depigmentation frequently start in the periphery and progress towards the posterior pole and can be encountered upon fundus biomicroscopy. Spectral-domain optical coherence tomography (SD-OCT) is an elegant tool for visualizing chorioretinal cystine crystals at the posterior pole. An SD-OCT-based clinical grading of the severity of the chorioretinal manifestation can potentially be applied as a biomarker for systemic disease status and for monitoring oral therapy adherence in the future. Along with previous histological examinations, it may also give information about the location of cystine crystals in the choroid and retina. This review aims to increase the awareness of vision-threatening retinal and choroidal changes in cystinosis and the concomitant findings in SD-OCT.
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Affiliation(s)
| | - Benedikt Schworm
- Department of Ophthalmology, Ludwig-Maximilians-University Munich, Germany
| | | | - Franziska Kruse
- Department of Ophthalmology, Ludwig-Maximilians-University Munich, Germany
| | | | - Nikolaus Luft
- Department of Ophthalmology, Ludwig-Maximilians-University Munich, Germany
| | - Claudia Priglinger
- Department of Ophthalmology, Ludwig-Maximilians-University Munich, Germany
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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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Keidel L, Elhardt C, Hohenfellner K, Priglinger S, Schworm B, Wertheimer C, Priglinger C, Luft N, Bechtold Dalla Pozza S, Bergmann C, Buss M, Dosch R, Erler J, Getzinger T, Herzig N, Hohenfellner K, Holla H, Knerr C, Koeppl C, Ockert C, Passow M, Rohayem J, Steidle G, Thiele A, Treikauskas U, Vill K, Weber R, Weitzel D. Establishing an objective biomarker for corneal cystinosis using a threshold-based Spectral domain optical coherence tomography imaging algorithm. Acta Ophthalmol 2021; 99:e189-e195. [PMID: 32833325 DOI: 10.1111/aos.14569] [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: 02/19/2020] [Revised: 06/24/2020] [Accepted: 07/02/2020] [Indexed: 12/01/2022]
Abstract
PURPOSE The purpose of the present study was to establish a semi-automated threshold-based image segmentation algorithm to detect and objectively quantify corneal cystine crystal deposition in ocular cystinosis with anterior segment optical coherence tomography (AS-OCT). METHODS This prospective, observational, comparative study included 88 eyes of 45 patients from the German Cystinosis Registry Study as well as 68 eyes of 35 healthy control subjects. All eyes were imaged with AS-OCT (Cirrus HD-OCT 5000, Carl Zeiss Meditec AG, Jena, Germany). As an initial step, B-scan images were subjectively analysed for typical changes in morphology in comparison to healthy controls. Based on the experience gained, an objective semi-automated B-scan image segmentation algorithm was developed using a grey scale value-based threshold method to automatically quantify corneal crystals. RESULTS On AS-OCT B-scans, corneal crystals appeared as hyperreflective deposits within the corneal stroma. The crystals were distributed either in all stromal layers (43 eyes, 49%) or confined to the anterior (23 eyes, 26%) or posterior stroma (22 eyes, 25%), respectively. The novel automatic B-scan image segmentation algorithm was most efficient in delineating corneal crystals at higher grey scale thresholds (e.g. 226 of a maximum of 255). Significant differences in suprathreshold grey scale pixels were observable between cystinosis patients and healthy controls (p < 0.001). In addition, the algorithm was able to detect an age-dependent depth distribution profile of crystal deposition. CONCLUSION Objective quantification of corneal cystine crystal deposition is feasible with AS-OCT and can serve as a novel biomarker for ocular disease control and topical treatment monitoring.
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Affiliation(s)
- Leonie Keidel
- Department of Ophthalmology Ludwig‐Maximilians‐University Munich Germany
| | - Carolin Elhardt
- Department of Ophthalmology Ludwig‐Maximilians‐University Munich Germany
| | | | | | - Benedikt Schworm
- Department of Ophthalmology Ludwig‐Maximilians‐University Munich Germany
| | | | - Claudia Priglinger
- Department of Ophthalmology Ludwig‐Maximilians‐University Munich Germany
| | - Nikolaus Luft
- Department of Ophthalmology Ludwig‐Maximilians‐University Munich Germany
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Papizh S, Serzhanova V, Filatova A, Skoblov M, Tabakov V, van den Heuvel L, Levtchenko E, Prikhodina L. CTNS mRNA molecular analysis revealed a novel mutation in a child with infantile nephropathic cystinosis: a case report. BMC Nephrol 2019; 20:400. [PMID: 31672123 PMCID: PMC6822415 DOI: 10.1186/s12882-019-1589-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 10/13/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cystinosis is an autosomal recessive lysosomal storage disorder characterized by accumulation of cystine in lysosomes throughout the body. Cystinosis is caused by mutations in the CTNS gene that encodes the lysosomal cystine carrier protein cystinosin. CTNS mutations result in either complete absence or reduced cystine transporting function of the protein. The diagnosis of nephropathic cystinosis is generally based on measuring leukocyte cystine level, demonstration of corneal cystine crystals by the slit lamp examination and confirmed by genetic analysis of the CTNS gene. CASE PRESENTATION A boy born to consanguineous Caucasian parents had the characteristic clinical features of the infantile nephropathic cystinosis including renal Fanconi syndrome (polydipsia/polyuria, metabolic acidosis, hypokalemia, hypophosphatemia, low molecular weight proteinuria, glycosuria, cystine crystals in the cornea) and elevated WBC cystine levels. Initially we performed RFLP analysis of the common in the Northern European population 57-kb deletion of proband's DNA, then a direct Sanger sequencing which revealed no mutations in the coding part of the CTNS gene. To confirm the diagnosis we performed RT-PCR analysis of total RNA obtained from patient-derived fibroblasts in combination with cDNA sequencing. This revealed the skipping of exon 4 and exon 5 in the CTNS in our patient. Therefore, we detected a novel 9-kb homozygous deletion in the CTNS gene at genomic DNA level, spanning region from intron 3 to intron 5. In order to identify the inheritance pattern of the deletion we analyzed DNA of proband's mother and father. Both parents were found to be heterozygous carriers of the CTNS mutation. CONCLUSIONS Analysis of CTNS gene transcript allowed to identify a large homozygous deletion in the patient with infantile nephropathic cystinosis. Mutational detection at RNA level may be an efficient tool to establish the genetic defect in some cystinosis patients.
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Affiliation(s)
- Svetlana Papizh
- Department of hereditary and acquired kidney diseases, Research and Clinical Institute for Pediatrics at the Pirogov Russian National Research Medical University, 125412, Taldomskaya st., 2, Moscow, Russia.
| | | | | | - Mikhail Skoblov
- Research Centre for Medical Genetics, 115522, Russia, Moscow
| | | | - Lambert van den Heuvel
- Department of Pediatrics/Pediatric Nephrology, University Hospital Gasthuisberg, Leuven, Belgium
| | - Elena Levtchenko
- Department of Pediatrics/Pediatric Nephrology, University Hospital Gasthuisberg, Leuven, Belgium
| | - Larisa Prikhodina
- Department of hereditary and acquired kidney diseases, Research and Clinical Institute for Pediatrics at the Pirogov Russian National Research Medical University, 125412, Taldomskaya st., 2, Moscow, Russia
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Li XQ, Wu D, Liang XJ, Li WJ, Liu M, Cao BY, Su C, Meng X, Gong CX. The diagnosis of cystinosis in patients reveals new CTNS gene mutations in the Chinese population. J Pediatr Endocrinol Metab 2019; 32:375-382. [PMID: 30849045 DOI: 10.1515/jpem-2018-0263] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 01/30/2019] [Indexed: 11/15/2022]
Abstract
Background Cystinosis is a rare autosomal-recessive disorder caused by a defective transport of cystine across the lysosomal membrane. Previous studies have mapped cystinosis to the CTNS gene which is located on chromosome 17p13, and various CTNS mutations have been identified to correlate them with this disease. Methods We analyzed six patients from five unrelated families who were diagnosed with cystinosis in our hospital. We described the diagnostic procedures for all the patients and proposed alternative therapies for cystinosis patients instead of using cysteamine, an orphan drug which was commercially unavailable in China. Moreover, genetic analysis of all patients' samples was carried out to identify novel CTNS gene mutations. Results and conclusions The patients in this study were followed up from 1 to more than 10 years to monitor their growth and development, which indicated that the alternative therapies we used were helpful to ameliorate the complications of the cystinosis patients without cysteamine. Furthermore, by sequencing the patients' genome, we identified novel mutations in the CTNS gene including: c.477C > G (p.S159R), c.274C > T (p.Q92X) and c.680A > T (p.E227V); these mutations were only observed in cystinosis patients and had never been reported in any other populations, suggesting they might be specific to Chinese cystinosis patients.
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Affiliation(s)
- Xiao-Qiao Li
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Di Wu
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Xue-Jun Liang
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Wen-Jing Li
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Min Liu
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Bing-Yan Cao
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Chang Su
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Xi Meng
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Chun-Xiu Gong
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
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Biswas S, Sornalingam K. The Ocular Status of Cystinosis Patients Receiving a Hospital Pharmacy-Made Preparation of Cysteamine Eye Drops: A Case Series. Ophthalmol Ther 2018; 8:125-136. [PMID: 30519924 PMCID: PMC6393247 DOI: 10.1007/s40123-018-0156-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Indexed: 12/01/2022] Open
Abstract
Introduction Infantile nephropathic cystinosis (INC) is an autosomal recessive lysosomal disorder in which patients develop deposits of cystine crystals in their kidneys and corneas from a young age. Methods We conducted a retrospective analysis of children with INC seen by ophthalmologists at the Manchester Royal Eye Hospital between 2002 and 2018, to evaluate clinical findings, symptoms and treatment. Results Twenty-two children diagnosed with INC from age 0 (prenatally) to 11 years were assessed. All evaluable patients had corneal cystine crystal deposits, and 15 had mild to moderate photophobia. Ten patients had other ocular conditions including blepharitis/chalzion (n = 6), swollen optic nerve (n = 3), punctate epitheliopathy (n = 3), corneal scarring (n = 1),and elevated intraocular pressure (n = 2). Confocal imaging identified nerve abnormalities in two patients (enlarged corneal nerve + abnormal-looking tortuous nerves in one patient and beaded nerves in the sub-basal plexus in the other), both of whom had significant crystal deposition in the anterior stroma. Visual acuity was relatively unaffected. All 22 patients were receiving oral cysteamine, and 21 were applying cysteamine eye drops (galenic preparation of 0.55% concentration, compounded by a hospital pharmacy). Recommended application frequency was at least eight times per day in all patients with dosing information available. Conclusions This case series of patients with INC highlights the consistent pattern of corneal cystine crystal deposition, which is universally present from a young age in this condition, and the high incidence of photophobia even in young children. Corneal manifestations of INC persisted despite frequent administration of the hospital pharmacy-made eye drop preparation. Reasons for this lack of efficacy may include the lag period between diagnosis and first prescription of cysteamine eye drops and the difficulty in maintaining rigorous compliance with this treatment. In addition, the challenge for patients of maintaining optimal storage conditions may adversely affect the stability and efficacy of cysteamine within this preparation. Funding Editorial assistance was funded by Orphan Europe Ltd.
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Affiliation(s)
- Susmito Biswas
- Manchester Royal Eye Hospital, Manchester Academic Health Science Centre, Manchester, UK.
| | - Krishanthy Sornalingam
- Manchester Royal Eye Hospital, Manchester Academic Health Science Centre, Manchester, UK
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Makuloluwa AK, Shams F. Cysteamine hydrochloride eye drop solution for the treatment of corneal cystine crystal deposits in patients with cystinosis: an evidence-based review. Clin Ophthalmol 2018; 12:227-236. [PMID: 29416314 PMCID: PMC5789046 DOI: 10.2147/opth.s133516] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Cystinosis is a rare, autosomal recessive disorder leading to defective transport of cystine out of lysosomes. Subsequent cystine crystal accumulation can occur in various tissues, including the ocular surface. This review explores the efficacy of cysteamine hydrochloride eye drops in the treatment of corneal cystine crystal accumulation and its safety profile.
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Affiliation(s)
| | - Fatemeh Shams
- Tennent Institute of Ophthalmology, Gartnavel General Hospital, Glasgow, UK
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Sadeghipour F, Basiratnia M, Derakhshan A, Fardaei M. Mutation analysis of the CTNS gene in Iranian patients with infantile nephropathic cystinosis: identification of two novel mutations. Hum Genome Var 2017; 4:17038. [PMID: 28983406 PMCID: PMC5628181 DOI: 10.1038/hgv.2017.38] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/07/2017] [Accepted: 07/09/2017] [Indexed: 12/02/2022] Open
Abstract
Nephropathic cystinosis is an inherited lysosomal transport disorder caused by mutations in the CTNS gene that encodes for a lysosomal membrane transporter, cystinosin. Dysfunction in this protein leads to cystine accumulation in the cells of different organs. The accumulation of cystine in the kidneys becomes apparent with renal tubular Fanconi syndrome between 6 and 12 months of age and leads to renal failure in the first decade of life. The aim of this study was to analyze the CTNS mutations in 20 Iranian patients, from 20 unrelated families, all of whom were afflicted with infantile nephropathic cystinosis. In these patients, seven different mutant alleles were found, including two new mutations, c.517T>C; p.Y173H and c.492_515del, that have not been previously reported. In addition, we observed that c.681G>A, the common Middle Eastern mutation, was the most common mutation in our patients. Moreover, a new minisatellite or variable number of tandem repeat marker (KX499495) was identified at the CTNS gene. Seven different alleles were found for this marker, and its allele frequency and heterozygosity degree were calculated in cystinosis patients and healthy individuals.
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Affiliation(s)
- Forough Sadeghipour
- Department of Medical Genetics, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mitra Basiratnia
- Department of Pediatric Nephrology, Namazi Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ali Derakhshan
- Department of Pediatric Nephrology, Namazi Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Majid Fardaei
- Department of Medical Genetics, Shiraz University of Medical Sciences, Shiraz, Iran.,Transgenic Technology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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Ghazi F, Hosseini R, Akouchekian M, Teimourian S, Ataei Kachoei Z, Otukesh H, Gahl WA, Behnam B. CTNS molecular genetics profile in a Persian nephropathic cystinosis population. Nefrologia 2017; 37:301-310. [PMID: 28238446 DOI: 10.1016/j.nefro.2016.11.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 09/18/2016] [Accepted: 11/22/2016] [Indexed: 11/27/2022] Open
Abstract
PURPOSE In this report, we document the CTNS gene mutations of 28 Iranian patients with nephropathic cystinosis age 1-17 years. All presented initially with severe failure to thrive, polyuria, and polydipsia. METHODS Cystinosis was primarily diagnosed by a pediatric nephrologist and then referred to the Iran University of Medical Sciences genetics clinic for consultation and molecular analysis, which involved polymerase chain reaction (PCR) amplification to determine the presence or absence of the 57-kb founder deletion in CTNS, followed by direct sequencing of the coding exons of CTNS. RESULTS The common 57-kb deletion was not observed in any of the 28 Iranian patients. In 14 of 28 patients (50%), mutations were observed in exons 6 and 7. No mutation was detected in exon 5, and only one (3.6%) patient with cystinosis showed a previously reported 4-bp deletion in exon 3 of CTNS. Four patients (14.3%) had a previously reported mutation (c.969C>A; p.N323K) in exon 11, and five (18%) had novel homozygous deletions in exon 6 leading to premature truncation of the protein. These deletions included c.323delA; p.Q108RfsX10 in three individuals and c.257-258delCT; p.S86FfsX37 in two cases. Other frame-shift mutations were all novel homozygous single base pair deletion/insertions including one in CTNS exon 9 (c.661insT; p.V221CfsX6), and four (14.3%) in exon 4, i.e., c.92insG; p.V31GfsX28 in two and c.120delC; p.T40TfsX10 in two. In total, we identified eight previously reported mutations and eight novel mutations in our patients. The only detected splice site mutation (IVS3-2A>C) was associated with the insertion mutation in the exon 9. CONCLUSION This study, the first molecular genetic analysis of non-ethnic-specific Iranian nephropathic cystinosis patients, may provide guidance for molecular diagnostics of cystinosis in Iran.
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Affiliation(s)
- Farideh Ghazi
- Department of Medical Genetics and Molecular Biology, Faculty of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Rozita Hosseini
- Department of Pediatrics, Faculty of Medicine, Ali Asghar Children Hospital, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Mansoureh Akouchekian
- Department of Medical Genetics and Molecular Biology, Faculty of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Shahram Teimourian
- Department of Medical Genetics and Molecular Biology, Faculty of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Zohreh Ataei Kachoei
- Department of Medical Genetics and Molecular Biology, Faculty of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Hassan Otukesh
- Department of Pediatrics, Faculty of Medicine, Ali Asghar Children Hospital, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - William A Gahl
- Section on Human Biochemical Genetics, Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA; NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, NIH, Bethesda, MD, USA
| | - Babak Behnam
- Department of Medical Genetics and Molecular Biology, Faculty of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran; Department of Pediatrics, Faculty of Medicine, Ali Asghar Children Hospital, Iran University of Medical Sciences (IUMS), Tehran, Iran; Section on Human Biochemical Genetics, Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA; NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, NIH, Bethesda, MD, USA.
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Doğan M, Bulan K, Kaba S, Cesur Y, Ceylaner S, Ustyol L. Cystinosis in Eastern Turkey. J Pediatr Endocrinol Metab 2016; 29:965-9. [PMID: 27269891 DOI: 10.1515/jpem-2014-0477] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 04/21/2016] [Indexed: 11/15/2022]
Abstract
BACKGROUND This study was conducted to investigate CTNS (cystinosin, lysosomal cystine transporter) gene mutations and the clinical spectrum of nephropathic cystinosis among patients diagnosed with the disease in a single center in Turkey. METHODS Patients' clinical and laboratory data were extracted from an electronic health registry. Molecular CTNS gene analysis was performed using either next-generation sequencing or Sanger sequencing. RESULTS Eleven patients (age range: 1.5-12 years) from nine families were identified. The presenting complaint was growth retardation in seven patients; polydipsia and polyuria in three patients; and vomiting in two patients. At presentation, electrolyte loss was noted in all patients, of which eight patients presented with metabolic acidosis, and three patients presented with metabolic alkalosis. All patients also presented with proteinuria and glucosuria, and four patients developed varying degrees of renal insufficiency, for which peritoneal dialysis was initiated in one patient. Cystine crystals were detected via ocular examination in one patient at presentation. No cystine crystals were detected among patients who underwent bone marrow aspiration. In the CTNS gene, a p.T7FX7 (c.18-21del4bp) mutation was detected in three patients, whereas a p.E227E (c.681 G>A) (homozygous) mutation was detected in eight patients. CONCLUSIONS We detected two distinct mutations, p.T7FX7 (c.18-21del4bp) and p.E227E (c.681 G>A) (homozygous), in the CTNS gene in 11 patients with cystinosis from the East Anatolian region of Turkey. Patients with a homozygous c.681 G>A (p.E227E) mutation are more likely to develop chronic renal failure and should be monitored closely, whereas patients with a p.T7FX7 (c.18-21del4bp) mutation have a milder phenotype. Additionally, metabolic alkalosis does not exclude cystinosis, although cystinosis is a cause of proximal renal tubular acidosis.
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Cheung WW, Cherqui S, Ding W, Esparza M, Zhou P, Shao J, Lieber RL, Mak RH. Muscle wasting and adipose tissue browning in infantile nephropathic cystinosis. J Cachexia Sarcopenia Muscle 2016; 7:152-64. [PMID: 27493869 PMCID: PMC4864942 DOI: 10.1002/jcsm.12056] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 04/21/2015] [Accepted: 06/03/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Muscle wasting is a common complication in patients with infantile nephropathic cystinosis, but its mechanism and association with energy metabolism is not known. We define the metabolic phenotype in Ctns(-/-) mice, an established murine model of infantile nephropathic cystinosis, with focus on muscle wasting and energy homeostasis. METHODS Male Ctns(-/-) mice and wild-type (WT) controls were studied at 1, 4, 9, and 12 months of age. As Ctns(-/-) mice started to develop chronic kidney disease (CKD) at 9 months of age, 9- and 12-month-old Ctns(-/-) mice were also compared with age-matched WT mice with CKD. Serum and urine chemistry and energy homeostasis parameters were measured. Skeletal muscle histomorphometry and in vivo muscle function were measured. We studied expression of genes involved in muscle mass regulation, thermogenesis, energy metabolism, adipogenesis, and adipose tissue browning in Ctns(-/-) mice. RESULTS Ctns(-/-) mice showed loss of weight and lean mass and increased energy expenditure. Ctns(-/-) mice exhibited abnormal energy homeostasis before the onset of their CKD. Food intake in Ctns(-/-) mice was comparable with age-matched WT controls. However, significantly lower total body mass starting at 1 month of age and increased energy expenditure at 4 months of age preceded the onset of CKD at 9 months of age in Ctns(-/-) mice. Muscle accept content in 1- and 4-month-old Ctns(-/-) mice was significantly lower than that in age-matched WT controls. At 12 months of age, muscle fibre area and in vivo muscle strength was reduced in Ctns(-/-) mice than that in WT or CKD controls. Muscle wasting in Ctns(-/-) mice was associated with inhibition of myogenesis, activation of muscle proteolysis pathways, and overexpression of pro-inflammatory cytokines. Increased energy expenditure was associated with elevation of thermogenesis in skeletal muscle and adipose tissues. The development of beige adipocytes in Ctns(-/-) mice is a novel finding. Expression of beige adipose cell surface markers (CD137, Tmem26, and Tbx1) and uncoupling protein-1, which is a brown adipose tissue marker, was observed in inguinal white adipose tissue of Ctns(-/-) mice. Expression of key molecules implicated in the pathogenesis of adipose tissue browning (Cox2, cytochrome c oxidase subunit II; PGF2α, prostaglandin F2α; IL-1α, interleukin 1α; IL-6, interleukin 6; TNF-α, tumor necrosis factor α) was significantly increased in inguinal white adipose tissue of Ctns(-/-) mice than that in WT controls. CONCLUSION This study describes a mouse model of nephropathic cystinosis presenting with profound muscle wasting. The mechanism for hypermetabolism in Ctns(-/-) mice may involve up-regulation of thermogenesis pathways in skeletal muscle and adipose tissues. This study demonstrates, for the first time, the development of beige adipocytes in Ctns(-/-) mice. Understanding the underlying mechanisms of adipose tissue browning in cystinosis may lead to novel therapy.
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Affiliation(s)
- Wai W Cheung
- Department of Pediatrics University of California San Diego CA USA
| | | | - Wei Ding
- Department of Pediatrics University of California San Diego CA USA; Division of Nephrology, The 5th People's Hospital of Shanghai Fudan University Shanghai China
| | - Mary Esparza
- Department of Orthopedic Surgery University of California San Diego CA USA
| | - Ping Zhou
- Department of Pediatrics University of California San Diego CA USA; Department of Pediatrics The 2nd Hospital of Harbin Medical University Harbin China
| | - Jianhua Shao
- Department of Pediatrics University of California San Diego CA USA
| | - Richard L Lieber
- Department of Orthopedic Surgery University of California San Diego CA USA; Rehabilitation Institute of Chicago Chicago
| | - Robert H Mak
- Department of Pediatrics University of California San Diego CA USA
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Won JY, Hwang HB, Chung SK. A case of corneal cystinosis in a patient with rickets and chronic renal failure. Indian J Ophthalmol 2015; 63:785-7. [PMID: 26655004 PMCID: PMC4728978 DOI: 10.4103/0301-4738.171509] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
A 22-year-old man diagnosed with nephropathic cystinosis at the age of 4 years was found to have progressive bilateral corneal crystal deposition. He presented with severe photophobia and decreased visual acuity. Ocular cystinosis was diagnosed on observing the typical crystals. Optical coherence tomography showed multiple areas of stromal hyperreflectivity due to crystal deposits within the corneal stroma. Ex vivo transmission electron microscopy of the cornea showed pathognomonic crystal deposits in corneal stromal keratocytes. Using polymerase chain reaction sequencing of the entire coding region, we identified five gene mutations, including two unreported mutations.
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Affiliation(s)
| | | | - Sung Kun Chung
- Department of Ophthalmology and Visual Science, St. Paul's Hospital, College of Medicine, The Catholic University of Korea, South Korea
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14
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Chiari I Malformation in Nephropathic Cystinosis. J Pediatr 2015; 167:1126-9. [PMID: 26265281 PMCID: PMC4661060 DOI: 10.1016/j.jpeds.2015.07.038] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 06/09/2015] [Accepted: 07/22/2015] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To determine the relative incidence of Chiari I malformations in children with cystinosis compared with those in the general population. STUDY DESIGN Magnetic resonance imaging scans were performed on 53 patients with nephropathic cystinosis and 120 controls, age range 3-18 years. RESULTS Ten of 53 (18.9%) patients with cystinosis had Chiari I or tonsillar ectopia, and only 2 of 120 controls (1.6%) had a similar finding. At least 2 of the patients had symptoms or signs thought to be related to the malformation, and one had surgical decompression. Two had an associated cervical syrinx. CONCLUSIONS Children with cystinosis have a 12-fold higher prevalence of Chiari I malformations than the general pediatric population. Chiari I malformations should be high on the differential diagnosis when individuals with cystinosis develop neurologic signs and symptoms, and magnetic resonance imaging scans should be performed on children with cystinosis who present with new-onset headache, ataxia, incontinence, or other unexplained neurologic symptoms.
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15
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Klusmann M, Van't Hoff W, Monsell F, Offiah AC. Progressive destructive bone changes in patients with cystinosis. Skeletal Radiol 2013; 43:387-391. [PMID: 24077756 DOI: 10.1007/s00256-013-1735-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 08/29/2013] [Accepted: 09/02/2013] [Indexed: 02/02/2023]
Abstract
Nephropathic cystinosis is an autosomal recessive lysosomal storage disorder in which intracellular cystine accumulates. It is caused by mutations in the CTNS gene. Clinical manifestations include renal tubular Fanconi syndrome in the first year of life, rickets, hypokalaemia, polyuria, dehydration and acidosis, growth retardation, hypothyroidism, photophobia and renal glomerular deterioration. Late complications include myopathy, pancreatic insufficiency and retinal blindness. Skeletal manifestations described in these patients include failure to thrive, osteomalacia, rickets and short stature. This paper describes progressive bony abnormalities in three unrelated patients with nephropathic cystinosis that have not been reported previously.
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Affiliation(s)
- Maria Klusmann
- Radiology, Imaging Department, University College Hospital, London, UK
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16
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Topaloğlu N, Tekin M, Yıldırım Ş, Gencer B. A rare case of cystinosis presenting with alkalosis. Ren Fail 2012; 35:279-81. [PMID: 23176067 DOI: 10.3109/0886022x.2012.745116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A 14-month-old girl was admitted to our clinic due to failure to thrive. Her weight and height were below the third percentile for age. Laboratory examination showed signs of alkalosis, hypokalemia, and hypochloremia. However, her urinalysis was consistent with renal tubular acidosis. Radiologic examination showed signs of active rickets. Based on clinical and laboratory findings, we focused on the probable diagnosis of cystinosis. Slit-lamp examination of the cornea confirmed our diagnosis. We should note that the presence of alkalosis does not exclude the possibility of diagnosis of cystinosis and we should be aware that if any slight doubt of cystinosis exists, patients should be carefully and completely evaluated for diagnosis.
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Affiliation(s)
- Naci Topaloğlu
- Department of Pediatrics, Medical Faculty, Çanakkale University, Çanakkale, Turkey.
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17
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Novel truncating mutation in the CTNS gene in an Egyptian family with cases of infantile nephropathic cystinosis and congenital heart malformations. ACTA ACUST UNITED AC 2012. [DOI: 10.1097/01.mxe.0000414810.01450.3c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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18
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Chiaverini C, Sillard L, Flori E, Ito S, Briganti S, Wakamatsu K, Fontas E, Berard E, Cailliez M, Cochat P, Foulard M, Guest G, Niaudet P, Picardo M, Bernard FX, Antignac C, Ortonne JP, Ballotti R. Cystinosin is a melanosomal protein that regulates melanin synthesis. FASEB J 2012; 26:3779-89. [PMID: 22649030 DOI: 10.1096/fj.11-201376] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cystinosis is a rare autosomal recessive disease characterized by cystine crystal accumulation leading to multiorgan dysfunctions and caused by mutation in CTNS. CTNS encodes cystinosin, a cystine/H(+) symporter that exports cystine out of the lysosomes. Patients with cystinosis frequently exhibit blond hair and fair complexion, suggesting an alteration in melanogenesis. However, the pigmentation singularities of these patients have not been studied, and the role of cystinosin in melanogenesis has remained unknown. In our study, a clinical evaluation of 27 patients with cystinosis showed that 44% had a cutaneous pigmentation dilution compared to their relatives. Analysis of the hair melanin content in these patients by HPLC demonstrated a 50% decrease in eumelanin (4360 vs. 9360 ng/mg), and a 2-fold increase in pheomelanin (53 vs. 20 ng/mg), the yellow/red pigments. Cystinosin-deficient mice also showed a 4-fold increase in hair pheomelanin content. In vitro studies showed that cystinosin was located at melanosomes. CTNS silencing led to a 75% reduction of melanin synthesis that was caused by a degradation of tyrosinase by lysosomal proteases. Our results objectify the pigmentation defect in patients with cystinosis. We also identify the role of CTNS in melanogenesis and add a new gene to the list of the genes involved in the control of skin and hair pigmentation.
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Affiliation(s)
- Christine Chiaverini
- Institut National de Santé et de Recherche Médical (INSERM), U1065, Centre Méditerranéen de Médecine Moléculaire, Equipe 1, Biology and Pathology of Melanocytes, Nice, France
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19
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Mechanism of proton/substrate coupling in the heptahelical lysosomal transporter cystinosin. Proc Natl Acad Sci U S A 2012; 109:E210-7. [PMID: 22232659 DOI: 10.1073/pnas.1115581109] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Secondary active transporters use electrochemical gradients provided by primary ion pumps to translocate metabolites or drugs "uphill" across membranes. Here we report the ion-coupling mechanism of cystinosin, an unusual eukaryotic, proton-driven transporter distantly related to the proton pump bacteriorhodopsin. In humans, cystinosin exports the proteolysis-derived dimeric amino acid cystine from lysosomes and is impaired in cystinosis. Using voltage-dependence analysis of steady-state and transient currents elicited by cystine and neutralization-scanning mutagenesis of conserved protonatable residues, we show that cystine binding is coupled to protonation of a clinically relevant aspartate buried in the membrane. Deuterium isotope substitution experiments are consistent with an access of this aspartate from the lysosomal lumen through a deep proton channel. This aspartate lies in one of the two PQ-loop motifs shared by cystinosin with a set of eukaryotic membrane proteins of unknown function and is conserved in about half of them, thus suggesting that other PQ-loop proteins may translocate protons.
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20
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Genetic basis of cystinosis in Turkish patients: a single-center experience. Pediatr Nephrol 2012; 27:115-21. [PMID: 21786142 PMCID: PMC3501933 DOI: 10.1007/s00467-011-1942-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2010] [Revised: 04/28/2011] [Accepted: 06/01/2011] [Indexed: 10/18/2022]
Abstract
We report the molecular findings for the CTNS gene in 12 Turkish cystinosis patients aged 7-29 years. All presented initially with severe failure to thrive, polyuria, and polydipsia. Cystinosis was diagnosed at age 1 month to 9 years. Seven patients reached end-stage renal failure at ages ranging from 6.5 to 15 years. Whereas three of the remaining five have renal Fanconi syndrome with proteinuria, two have had kidney failure of varying degrees. Molecular analyses involved an initial multiplex polymerase chain reaction (PCR) to determine the presence or absence of the 57-kb northern European founder deletion in CTNS, followed by sequencing of the ten coding exons of CTNS. Comprehensive mutation analysis verified that none of the 12 patients carried the common 57-kb deletion. We identified four previously reported nucleotide variations associated with cystinosis and five new variants: a 10-kb deletion, three missense variants, and a nucleotide substitution in a potential branch point site of intron 4. This study is the first molecular analysis of Turkish cystinosis patients and provides guidance for the molecular diagnosis of cystinosis in this population.
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21
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Caltik A, Akyüz SG, Erdogan O, Bülbül M, Demircin G. Rare presentation of cystinosis mimicking Bartter's syndrome: reports of two patients and review of the literature. Ren Fail 2010; 32:277-80. [PMID: 20199192 DOI: 10.3109/08860221003592804] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We present here two girls with cystinosis initially diagnosed as Bartter syndrome. Both cases were admitted with hypokalemic, hypochloremic alkalosis. Their proximal tubular functions, ophthalmologic and bone marrow examinations were normal. They were started on therapies with the diagnosis of Bartter syndrome. The first patient developed signs of rickets, and the second patient was lost to follow-up and readmitted with chronic renal failure. On reevaluation cystine crystals were detected in cornea and bone marrow aspirates of both patients. We aimed to remind the rare presentation of cystinosis with metabolic alkalosis mimicking Bartter syndrome by these two cases and review the literature.
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Affiliation(s)
- Aysun Caltik
- Dr. Sami Ulus Children Hospital, Pediatric Nephrology Department, Altindag, Ankara, Turkey.
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22
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Min-Oo G, Ayi K, Bongfen SE, Tam M, Radovanovic I, Gauthier S, Santiago H, Rothfuchs AG, Roffê E, Sher A, Mullick A, Fortin A, Stevenson MM, Kain KC, Gros P. Cysteamine, the natural metabolite of pantetheinase, shows specific activity against Plasmodium. Exp Parasitol 2010; 125:315-24. [PMID: 20219464 DOI: 10.1016/j.exppara.2010.02.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Revised: 01/21/2010] [Accepted: 02/22/2010] [Indexed: 11/26/2022]
Abstract
In mice, loss of pantetheinase activity causes susceptibility to infection with Plasmodium chabaudi AS. Treatment of mice with the pantetheinase metabolite cysteamine reduces blood-stage replication of P. chabaudi and significantly increases survival. Similarly, a short exposure of Plasmodium to cysteamine ex vivo is sufficient to suppress parasite infectivity in vivo. This effect of cysteamine is specific and not observed with a related thiol (dimercaptosuccinic acid) or with the pantethine precursor of cysteamine. Also, cysteamine does not protect against infection with the parasite Trypanosoma cruzi or the fungal pathogen Candida albicans, suggesting cysteamine acts directly against the parasite and does not modulate host inflammatory response. Cysteamine exposure also blocks replication of P. falciparum in vitro; moreover, these treated parasites show higher levels of intact hemoglobin. This study highlights the in vivo action of cysteamine against Plasmodium and provides further evidence for the involvement of pantetheinase in host response to this infection.
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Affiliation(s)
- Gundula Min-Oo
- Department of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montréal, QC, Canada
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23
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24
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Kessler A, Biasibetti M, Feksa LR, Rech VC, Melo DADS, Wajner M, Dutra-Filho CS, Wyse ATDS, Wannmacher CMD. Effects of cysteamine on oxidative status in cerebral cortex of rats. Metab Brain Dis 2008; 23:81-93. [PMID: 18030610 DOI: 10.1007/s11011-007-9078-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2007] [Accepted: 08/01/2007] [Indexed: 10/22/2022]
Abstract
Cystinosis is a systemic genetic disease caused by a lysosomal transport deficiency accumulating cystine in most tissues. Tissue damage depends on cystine accumulation, but the mechanisms of this damage are still obscure. Cysteamine administration depletes cystine accumulated, increasing survive of affected patients. Studies performed in fibroblasts of cystinotic patients suggest that apoptosis is enhanced in this disease. Considering that oxidative stress is a known apoptosis inducer, our main objective was to investigate a possible antioxidant effect of cysteamine on several parameters of oxidative stress in the brain of young rats. Animals received three subcutaneous injections at 3-h intervals of a buffered solution (pH 7.4) of 10 mg/kg body weight cysteamine and were sacrificed 1 h after the last injection. Cysteamine decreased lipoperoxidation and glutathione peroxidase activity, and increased the carbonyl content of proteins and catalase activity. In vitro studies showed that cysteamine reduced lipoperoxidation, 2',7'-dihydrodichlorofluorescein oxidation, carbonyl content of proteins and catalase activity, and increased glutathione peroxidase activity. These results suggest that cysteamine may act as a scavenger of superoxide free radicals and hydrogen peroxide. Therefore, it is possible that cysteamine may extend life of cystinotic patients acting not only as a cystine depleting drug, but also as a free radical scavenger, reducing cell damage by apoptosis.
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Affiliation(s)
- Adriana Kessler
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600, CEP 90.035-003, Porto Alegre, Rio Grande do Sul, Brazil
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25
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Mannucci L, Pastore A, Rizzo C, Piemonte F, Rizzoni G, Emma F. Impaired activity of the gamma-glutamyl cycle in nephropathic cystinosis fibroblasts. Pediatr Res 2006; 59:332-5. [PMID: 16439602 DOI: 10.1203/01.pdr.0000196370.57200.da] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cystinotic patients have been shown to excrete in their urine high levels of pyroglutamate, an intermediate metabolite of the adenosine triphosphate (ATP)-dependent gamma-glutamyl cycle, which is responsible for glutathione (GSH) synthesis. Human fibroblasts were used to study the mechanisms leading to pyroglutamate accumulation in nephropathic cystinosis (NC). We show that inhibition of ATP synthesis caused a marked intracellular accumulation of pyroglutamate, reflecting decreased GSH synthesis. Despite similar degrees of ATP depletion, pyroglutamate increased more in cystinotic fibroblasts than in controls, while GSH decreased to lower levels. In addition, cystinotic cells exposed to oxidative stress (hydrogen peroxide) were unable to increase their GSH concentration above baseline. These results could not be attributed to differences in mitochondrial oxidative activity or to increased apoptotic cell death. Together, these results support the hypothesis that cysteine derived from lysosomal cystine efflux limits the activity of the gamma-glutamyl cycle and GSH synthesis.
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Affiliation(s)
- Liliana Mannucci
- Department of Nephrology and Urology, Bambino Gesù Children's Hospital and Research Institute, Rome, Italy
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26
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Christensen EI, Nielsen R. Role of megalin and cubilin in renal physiology and pathophysiology. Rev Physiol Biochem Pharmacol 2006; 158:1-22. [PMID: 17729440 DOI: 10.1007/112_0604] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Megalin and cubilin are endocytic receptors highly expressed in the endocytic apparatus of the renal proximal tubule. These receptors appear to be responsible for the tubular clearance of most proteins filtered in the glomeruli. Cubilin is a peripheral membrane protein, and therefore it does not have an endocytosis signaling sequence. It appears that megalin is responsible for internalization of cubilin and its ligands in addition to internalizing its own ligands. The proteinuria observed in megalin-deficient mice, in dogs lacking functional cubilin, and in patients with distinct mutations of the cubilin gene illustrates the importance of the receptors.
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Affiliation(s)
- E I Christensen
- University of Aarhus, Department of Cell Biology, Institute of Anatomy, University Park, Building 234, 8000 Aarhus C, Denmark.
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27
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Infantile cystinosis. Arch Pathol Lab Med 2005; 129:126-7. [PMID: 15628899 DOI: 10.5858/2005-129-126-ic] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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28
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Christensen EI, Gburek J. Protein reabsorption in renal proximal tubule-function and dysfunction in kidney pathophysiology. Pediatr Nephrol 2004; 19:714-21. [PMID: 15146321 DOI: 10.1007/s00467-004-1494-0] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2003] [Revised: 03/24/2004] [Accepted: 03/25/2004] [Indexed: 10/26/2022]
Abstract
The endocytic receptors megalin and cubilin are highly expressed in the early parts of the endocytic apparatus of the renal proximal tubule. The two receptors appear to be responsible for the tubular clearance of most proteins filtered in the glomeruli. Since cubilin is a peripheral membrane protein it has no endocytosis signaling sequence. Cubilin binds to megalin and it appears that megalin is responsible for internalization of cubilin and its ligands, in addition to internalizing its own ligands. The importance of the receptors is underscored by the proteinuria observed in megalin-deficient mice, in dogs lacking functional cubilin, and in patients with distinct mutations of the cubilin gene. In this review we focus on the role of megalin- and cubilin-mediated endocytosis in renal pathophysiology. Association between disorders characterized by tubular proteinuria, such as megaloblastic anemia type-1, Dent disease, cystinosis, and Fabry disease and the dysfunction of proximal tubular endocytosis is discussed. The correlation between the high capacity of endocytosis in the proximal tubule and progressive renal disease in overload proteinuria is considered.
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Affiliation(s)
- Erik I Christensen
- Department of Cell Biology, Institute of Anatomy, University of Aarhus, 8000 Aarhus C, Denmark.
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