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Medaer L, David D, Smits M, Levtchenko E, Sampaolesi M, Gijsbers R. Residual Cystine Transport Activity for Specific Infantile and Juvenile CTNS Mutations in a PTEC-Based Addback Model. Cells 2024; 13:646. [PMID: 38607085 PMCID: PMC11011962 DOI: 10.3390/cells13070646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 04/03/2024] [Accepted: 04/04/2024] [Indexed: 04/13/2024] Open
Abstract
Cystinosis is a rare, autosomal recessive, lysosomal storage disease caused by mutations in the gene CTNS, leading to cystine accumulation in the lysosomes. While cysteamine lowers the cystine levels, it does not cure the disease, suggesting that CTNS exerts additional functions besides cystine transport. This study investigated the impact of infantile and juvenile CTNS mutations with discrepant genotype/phenotype correlations on CTNS expression, and subcellular localisation and function in clinically relevant cystinosis cell models to better understand the link between genotype and CTNS function. Using CTNS-depleted proximal tubule epithelial cells and patient-derived fibroblasts, we expressed a selection of CTNSmutants under various promoters. EF1a-driven expression led to substantial overexpression, resulting in CTNS protein levels that localised to the lysosomal compartment. All CTNSmutants tested also reversed cystine accumulation, indicating that CTNSmutants still exert transport activity, possibly due to the overexpression conditions. Surprisingly, even CTNSmutants expression driven by the less potent CTNS and EFS promoters reversed the cystine accumulation, contrary to the CTNSG339R missense mutant. Taken together, our findings shed new light on CTNS mutations, highlighting the need for robust assessment methodologies in clinically relevant cellular models and thus paving the way for better stratification of cystinosis patients, and advocating for the development of more personalized therapy.
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Affiliation(s)
- Louise Medaer
- Laboratory of Molecular Virology and Gene Therapy, Department of Pharmacological and Pharmaceutical Sciences, Faculty of Medicine, KU Leuven, 3000 Leuven, Belgium; (L.M.); (M.S.)
| | - Dries David
- Laboratory of Molecular Virology and Gene Therapy, Department of Pharmacological and Pharmaceutical Sciences, Faculty of Medicine, KU Leuven, 3000 Leuven, Belgium; (L.M.); (M.S.)
| | - Maxime Smits
- Laboratory of Molecular Virology and Gene Therapy, Department of Pharmacological and Pharmaceutical Sciences, Faculty of Medicine, KU Leuven, 3000 Leuven, Belgium; (L.M.); (M.S.)
- Leuven Viral Vector Core, Faculty of Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Elena Levtchenko
- Department of Paediatric Nephrology & Development and Regeneration, University Hospitals Leuven & KU Leuven, 3000 Leuven, Belgium;
- Department of Paediatric Nephrology, Amsterdam University Medical Centre, 1081 Amsterdam, The Netherlands
| | - Maurilio Sampaolesi
- Translational Cardiology Laboratory, Department of Development and Regeneration, Stem Cell Institute, Faculty of Medicine, KU Leuven, 3000 Leuven, Belgium;
| | - Rik Gijsbers
- Laboratory of Molecular Virology and Gene Therapy, Department of Pharmacological and Pharmaceutical Sciences, Faculty of Medicine, KU Leuven, 3000 Leuven, Belgium; (L.M.); (M.S.)
- Leuven Viral Vector Core, Faculty of Medicine, KU Leuven, 3000 Leuven, Belgium
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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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Guan YJ, Guo YN, Peng WT, Liu LL. Case Report: Cystinosis in a Chinese Child With a Novel CTNS Pathogenic Variant. Front Pediatr 2022; 10:860990. [PMID: 35498770 PMCID: PMC9051362 DOI: 10.3389/fped.2022.860990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 03/21/2022] [Indexed: 11/28/2022] Open
Abstract
OBJECTIVE To report a rare case of cystinosis with a novel CTNS pathogenic variant in the Chinese population. METHODS Retrospective analysis of the clinical manifestations, laboratory results, and gene detection data of a child with cystinosis. RESULTS A Chinese Zang ethnic girl could not stand or walk until 3 years old, with additional symptoms including a loss of appetite. Since then, the girl gradually exhibited "X" leg, double wrist joints, a bilateral ankle deformity, and rickets. At the age of 9 years, the girl was hospitalized. Laboratory testing showed that her blood phosphorus, blood calcium and blood potassium levels were significantly decreased. At the same time, the girl's urine glucose and urine protein were positive, although her fasting blood glucose, glycosylated hemoglobin, and 75 g glucose tolerance were not significantly abnormal. Further, blood gas analysis showed metabolic acidosis. These symptoms corresponded to Fanconi syndrome. Gene analysis showed that there was a homozygous pathogenic variant c.140 ≤ 5G > A (p.?) in the CTNS gene, which was a small variation in the intron region. To our knowledge, this is the first report of the rare variant. CONCLUSION Attention should be paid to the differential diagnosis of cystinosis by gene analysis in children whose clinical manifestations include exercise dysplasia, renal damage, or multiple organ damage (including bone, thyroid, etc) and who cannot be firmly diagnosed for the time being.
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Affiliation(s)
- Yu-Jia Guan
- Department of Nursing, West China Second University Hospital, Sichuan University, Chengdu, China.,West China School of Nursing, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, China
| | - Yan-Nan Guo
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, China.,Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Wen-Tao Peng
- Department of Nursing, West China Second University Hospital, Sichuan University, Chengdu, China.,West China School of Nursing, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, China
| | - Li-Li Liu
- Department of Nursing, West China Second University Hospital, Sichuan University, Chengdu, China.,West China School of Nursing, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, China
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Tokhmafshan F, Dickinson K, Akpa MM, Brasell E, Huertas P, Goodyer PR. A no-nonsense approach to hereditary kidney disease. Pediatr Nephrol 2020; 35:2031-2042. [PMID: 31807928 DOI: 10.1007/s00467-019-04394-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 07/05/2019] [Accepted: 10/07/2019] [Indexed: 01/12/2023]
Abstract
The advent of a new class of aminoglycosides with increased translational readthrough of nonsense mutations and reduced toxicity offers a new therapeutic strategy for a subset of patients with hereditary kidney disease. The renal uptake and retention of aminoglycosides at a high intracellular concentration makes the kidney an ideal target for this approach. In this review, we explore the potential of aminoglycoside readthrough therapy in a number of hereditary kidney diseases and discuss the therapeutic window of opportunity for subclasses of each disease, when caused by nonsense mutations.
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Affiliation(s)
- Fatima Tokhmafshan
- Research Institute of the McGill University Health Center, 1001 Décarie Boulevard, EM1.2232, Montreal, QC, H4A 3J1, Canada
| | - Kyle Dickinson
- Research Institute of the McGill University Health Center, 1001 Décarie Boulevard, EM1.2232, Montreal, QC, H4A 3J1, Canada.,Department of Experimental Medicine, McGill University, Montreal, Canada
| | - Murielle M Akpa
- Research Institute of the McGill University Health Center, 1001 Décarie Boulevard, EM1.2232, Montreal, QC, H4A 3J1, Canada
| | - Emma Brasell
- Department of Human Genetics, McGill University, Montreal, Canada
| | | | - Paul R Goodyer
- Research Institute of the McGill University Health Center, 1001 Décarie Boulevard, EM1.2232, Montreal, QC, H4A 3J1, Canada. .,Department of Experimental Medicine, McGill University, Montreal, Canada. .,Department of Human Genetics, McGill University, Montreal, Canada. .,Department of Pediatrics, McGill University, Montreal, Canada.
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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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Najafi M, Tamandani DMK, Azarfar A, Bakey Z, Behjati F, Antony D, Schüle I, Sadeghi-Bojd S, Karimiani EG, Schmidts M. A 57 kB Genomic Deletion Causing CTNS Loss of Function Contributes to the CTNS Mutational Spectrum in the Middle East. Front Pediatr 2019; 7:89. [PMID: 30949462 PMCID: PMC6437787 DOI: 10.3389/fped.2019.00089] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 02/28/2019] [Indexed: 12/03/2022] Open
Abstract
Background: Nephropathic Cystinosis, the most common cause of renal Fanconi syndrome, is a lysosomal transport disorder with an autosomal recessive inheritance pattern. A large number of mutations in CTNS have been identified as causative to date. A 57 kb deletion encompassing parts of CTNS is most commonly identified in Caucasians but this allele has not been identified in individuals of Eastern Mediterranean, Middle Eastern, Persian, or Arab origin to date. Methods and Results: Implementing whole exome sequencing (WES) in a consanguineous Iranian family, we identified this large deletion affecting CTNS in a patient initially presenting with hypokalemic metabolic alkalosis symptoms and considerable proteinuria. Conclusion: We show WES is a cost and time efficient genetic diagnostics modality to identify the underlying molecular pathology in Cystinosis individuals and provide a summary of all previously reported CTNS alleles in the Middle east population. Our work also highlights the importance to consider the 57-kb deletion as underlying genetic cause in non-European populations, including the Middle East. Limited diagnostic modalities for Cystinosis in developing countries could account for the lack of previously reported cases in these populations carrying this allele. Further, our findings emphasize the utility of WES to define genetic causes in clinically poorly defined phenotypes and demonstrate the requirement of Copy number variation (CNV) analysis of WES data.
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Affiliation(s)
- Maryam Najafi
- Genome Research Division, Human Genetics Department, Radboud University Medical Center Nijmegen and Radboud Institute for Molecular Life Sciences, Nijmegen, Netherlands.,Department of Biology, University of Sistan and Baluchestan, Zahedan, Iran
| | | | - Anoush Azarfar
- Department of Pediatrics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Zeineb Bakey
- Genome Research Division, Human Genetics Department, Radboud University Medical Center Nijmegen and Radboud Institute for Molecular Life Sciences, Nijmegen, Netherlands.,Center for Pediatrics and Adolescent Medicine, Faculty of Medicine, University Hospital Freiburg, Freiburg University, Freiburg, Germany
| | - Farkhondeh Behjati
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Dinu Antony
- Genome Research Division, Human Genetics Department, Radboud University Medical Center Nijmegen and Radboud Institute for Molecular Life Sciences, Nijmegen, Netherlands.,Center for Pediatrics and Adolescent Medicine, Faculty of Medicine, University Hospital Freiburg, Freiburg University, Freiburg, Germany
| | - Isabel Schüle
- Center for Pediatrics and Adolescent Medicine, Faculty of Medicine, University Hospital Freiburg, Freiburg University, Freiburg, Germany
| | - Simin Sadeghi-Bojd
- Children and Adolescents Health Research Center, Resistant Tuberculosis Institute, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Ehsan Ghayoor Karimiani
- Next Generation Genetic Polyclinic, Mashhad, Iran.,Razavi Cancer Research, Razavi Hospital, Imam Reza International University, Mashhad, Iran
| | - Miriam Schmidts
- Genome Research Division, Human Genetics Department, Radboud University Medical Center Nijmegen and Radboud Institute for Molecular Life Sciences, Nijmegen, Netherlands.,Center for Pediatrics and Adolescent Medicine, Faculty of Medicine, University Hospital Freiburg, Freiburg University, Freiburg, Germany
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Deshpande AA, Shukla A, Bachhawat AK. A Genetic Screen for Investigating the Human Lysosomal CystineTransporter, Cystinosin. Sci Rep 2018; 8:3442. [PMID: 29467429 PMCID: PMC5821828 DOI: 10.1038/s41598-018-21483-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 02/06/2018] [Indexed: 11/09/2022] Open
Abstract
Cystinosin, a lysosomal transporter is involved in the efflux of cystine from the lysosome to the cytosol. Mutations in the human cystinosin gene (CTNS) cause cystinosis, a recessive autosomal disorder. Studies on cystinosin have been limited by the absence of a robust genetic screen. In the present study we have developed a dual strategy for evaluating cystinosin function that is amenable to rapid genetic analysis. We show that human cystinosin expressed in this yeast confers growth on cystine when the protein is mistargeted to the plasma membrane by the deletion of the C-terminal targeting signal, GYQDL. We also screened a vacuolar protein sorting deletion library, and subsequently created multiple vps deletion mutants for kinetic studies. The double deletion, vps1Δvps17Δ, greatly enhanced uptake. This enabled validation by kinetic studies, including first studies on the WT CTNS protein (that contained the GYQDL motif). Using this screen we isolated several gain of function mutants, G131S/D, G309S/D, A137V, G197R, S270T, L274F and S312N showing enhanced growth on low concentrations of cystine. Kinetic analysis yielded insights into the role of the residues (including one of the patient mutations, G197R). The results indicate that the screen could be effectively used for interrogating and understanding the CTNS protein.
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Affiliation(s)
- Anup Arunrao Deshpande
- Indian Institute of Science and Education Research Mohali, Sector 81, Knowledge City, SAS Nagar, Punjab, India
| | - Anuj Shukla
- Indian Institute of Science and Education Research Mohali, Sector 81, Knowledge City, SAS Nagar, Punjab, India
| | - Anand Kumar Bachhawat
- Indian Institute of Science and Education Research Mohali, Sector 81, Knowledge City, SAS Nagar, Punjab, India.
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8
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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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Jaradat S, Al-Rababah B, Hazza I, Akl K, Saca E, Al-Younis D. Molecular analysis of the CTNS gene in Jordanian families with nephropathic cystinosis. Nefrologia 2015; 35:547-53. [DOI: 10.1016/j.nefro.2015.09.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 06/10/2015] [Indexed: 10/22/2022] Open
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10
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Common mutation causes cystinosis in the majority of black South African patients. Pediatr Nephrol 2015; 30:595-601. [PMID: 25326109 DOI: 10.1007/s00467-014-2980-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 09/03/2014] [Accepted: 09/29/2014] [Indexed: 01/01/2023]
Abstract
BACKGROUND The mutations responsible for cystinosis in South African patients are currently unknown. A pertinent question is whether they are similar to those described elsewhere in the world. METHODS Children who were being managed for cystinosis in the Western Cape Province of South Africa between 2002 and 2013 were studied. All underwent molecular analysis to detect sequence variations in the cystinosis gene. RESULTS This cohort study included 20 patients, 13 of whom were Xhosa-speaking black South Africans and seven were Cape Coloureds (mixed race); none were Caucasian. All had nephropathic infantile-type cystinosis with evidence of proximal tubulopathy, with glycosuria and renal phosphate wasting. Diagnosis was confirmed in 19 cases by demonstrating an elevated cystine concentration in leukocytes. Molecular analysis of the cystinosin gene revealed that 19 patients had a G > A mutation in intron 11 (CTNS-c.971-12G > A p.D324AfsX44) which caused an out-of-frame 10-bp insertion. Of these 19 patients, 16 were homozygous for this mutation, which was the most frequent mutation identified in the alleles of the black South African and Cape Coloured patients (96 and 71 %, respectively). CONCLUSION We recommend that black South African and Cape Coloured patients presenting with cystinosis be tested for CTNS-c.971-12G > A in the first instance, with the possibility of prenatal testing being offered to at-risk families.
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11
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First report of CTNS mutations in a Chinese family with infantile cystinosis. ScientificWorldJournal 2015; 2015:309410. [PMID: 25866837 PMCID: PMC4381850 DOI: 10.1155/2015/309410] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 03/02/2015] [Indexed: 11/24/2022] Open
Abstract
Infantile cystinosis (IC) is a rare autosomal recessive disorder characterized by a defect in the lysosomal-membrane transport protein, cystinosin. It serves as a prototype for lysosomal transport disorders. To date, several CTNS mutations have been identified as the cause of the prototypic disease across different ethnic populations worldwide. However, in Asia, the CTNS mutation is very rarely reported. For the Chinese population, no literature on CTNS mutation screening for IC is available to date. In this paper, by using the whole exome sequencing and Sanger sequencing, we identified two novel CTNS splicing deletions in a Chinese IC family, one at the donor site of exon 6 of CTNS (IVS6+1, del G) and the other at the acceptor site of exon 8 (IVS8-1, del GT). These data give information for the genetic counseling of the IC that occurred in Chinese population.
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12
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Soliman NA, Elmonem MA, van den Heuvel L, Abdel Hamid RH, Gamal M, Bongaers I, Marie S, Levtchenko E. Mutational Spectrum of the CTNS Gene in Egyptian Patients with Nephropathic Cystinosis. JIMD Rep 2014; 14:87-97. [PMID: 24464559 DOI: 10.1007/8904_2013_288] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 12/02/2013] [Accepted: 12/05/2013] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Nephropathic cystinosis is a rare autosomal recessive disorder caused by mutations in the CTNS gene, encoding for cystinosin, a carrier protein transporting cystine out of lysosomes. Its deficiency leads to cystine accumulation and cell damage in multiple organs, especially in the kidney. In this study, we aimed to provide the first report describing the mutational spectrum of Egyptian patients with nephropathic cystinosis and their genotype-phenotype correlation. METHODS Fifteen Egyptian patients from 13 unrelated families with infantile nephropathic cystinosis were evaluated clinically, biochemically, and genetically. Screening for the common 57-kb deletion was performed by standard multiplex PCR, followed by direct sequencing of the ten coding exons, exon-intron interfaces, and promoter region. RESULTS None of the 15 Egyptian patients had the 57-kb deletion. Twenty-seven mutant alleles and 12 pathogenic mutations were detected including six novel mutations: two frameshift (c.260_261delTT; p.F87SfsX36, c.1032delCinsTG; p.F345CfsX19), one nonsense (c.734G>A; p.W245fsX), two missense (c.1084G>A; pG362R, c.560A>G; p.K187R), and one intronic splicing mutation (IVS3+5g>t). A novel promoter region mutation (1-593-41C>T) seemed to be detected but was excluded as a pathogenic mutation by quantitative real-time PCR analysis. CONCLUSIONS This study could be the basis for future genetic counseling and prenatal diagnosis of patients with nephropathic cystinosis in Egyptian and surrounding populations. The screening for the 57-kb deletion is not recommended anymore outside its geographical distribution, especially in the region of the Middle East. A common Middle Eastern mutation (c.681G>A; E227E) was pointed out and discussed.
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Affiliation(s)
- Neveen A Soliman
- Department of Pediatrics, Center of Pediatric Nephrology and Transplantation (CPNT), Cairo University, Cairo, Egypt
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