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1.
Indian J Pathol Microbiol ; 62(3): 457-460, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31361240

RESUMO

Nephropathic cystinosis is a rare autosomal recessive lysosomal disease characterized by accumulation of pathognomonic cystine crystals in renal and other tissues of the body. Cystinosis is caused by mutant cystinosin, the cystine transport protein located in lysosomal membranes, leading to systemic deposits of cystine and resultant end organ damage. Cystinosis is rarer in Asians than Caucasians with only a handful of cases reported from India to date. Due to its extreme rarity and clinically insidious presentation in contrast to the infantile form, the diagnosis of juvenile nephropathic cystinosis is frequently delayed or overlooked. Moreover, routine processing and sectioning of paraffin embedded tissues dissolves cystine crystals, making it difficult to diagnose this condition on light microscopic examination alone, mandating electron microscopic (EM) analysis of renal biopsies for an accurate diagnosis of this condition. We describe a case of juvenile nephropathic cystinosis presenting with uveitis and photophobia in a 17-year-old Indian male, diagnosed after EM examination of the patient's renal biopsy for evaluation of nephrotic syndrome. While highlighting the diagnostic utility of EM, we describe a few histopathologic clues which can prompt inclusion of EM analysis of renal biopsies in this setting.


Assuntos
Cistinose/diagnóstico , Síndrome Nefrótica/diagnóstico , Uveíte/diagnóstico , Adolescente , Sistemas de Transporte de Aminoácidos Neutros/genética , Biópsia , Cistina/metabolismo , Cistinose/genética , Humanos , Rim/patologia , Rim/ultraestrutura , Masculino , Microscopia Eletrônica , Síndrome Nefrótica/genética , Fotofobia/etiologia , Transtornos da Visão/etiologia
2.
Ophthalmic Genet ; 40(2): 157-160, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30957593

RESUMO

BACKGROUND: Ocular cystinosis is a rare autosomal recessive disorder caused by one severe and one mild mutation in the CTNS gene. It is characterised by cystine deposition within the cornea and conjunctiva however, the kidneys are not affected. We report a case of ocular cystinosis caused by two potentially severe CTNS mutations and discuss the possible mechanism of renal sparing. METHODS: This is an observational case report of the proband and her unaffected relatives. All subjects underwent ophthalmic examination, whilst in the proband, In vivo laser scanning confocal microscopy was used to demonstrate cystine crystals within her corneas and conjunctiva. Genetic diagnosis was confirmed by DNA sequencing of the proband and the segregation of the mutations was established in her relatives. RT-PCR of leukocyte RNA was undertaken to determine if aberrant splicing of the CTNS gene was taking place Results: The proband was found to have cystine crystals limited to the anterior corneal stroma and the conjunctiva. Sequencing of the proband's CTNS gene found her to be a compound heterozygote for a 27bp deletion in exon8/intron 8 (c.559_561 + 24del) and a novel c.635C>T variant in exon 9 that is predicted be pathogenic and to result in the substitution of alanine with valine at amino acid position 212 (p.Ala212Val), which is within the 3rd transmembrane spanning domain of the CTNS protein. Examination of the proband's leukocyte RNA failed to demonstrate any aberrant CTNS gene splicing. CONCLUSION: We present a case of ocular cystinosis caused by two potentially severe CTNS gene mutations. The lack of renal involvement may be due to localised (ocular) aberrant CTNS RNA splicing.


Assuntos
Sistemas de Transporte de Aminoácidos Neutros/genética , Doenças da Túnica Conjuntiva/genética , Doenças da Córnea/genética , Cistinose/genética , Mutação , Adulto , Doenças da Túnica Conjuntiva/diagnóstico , Doenças da Córnea/diagnóstico , Cistinose/diagnóstico , Feminino , Estudos de Associação Genética , Heterozigoto , Humanos , Microscopia Confocal , Microscopia Eletrônica de Transmissão , Linhagem , Processamento de RNA/genética , Reação em Cadeia da Polimerase em Tempo Real , Análise de Sequência de DNA , Microscopia com Lâmpada de Fenda
3.
J Pediatr Endocrinol Metab ; 32(4): 375-382, 2019 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-30849045

RESUMO

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.


Assuntos
Sistemas de Transporte de Aminoácidos Neutros/genética , Cistinose/diagnóstico , Genética Populacional , Mutação , Adolescente , Criança , Pré-Escolar , China/epidemiologia , Cistinose/tratamento farmacológico , Cistinose/epidemiologia , Cistinose/genética , Feminino , Seguimentos , Hormônio do Crescimento Humano/administração & dosagem , Humanos , Lactente , Masculino , Linhagem , Prognóstico
4.
Pediatr Nephrol ; 34(4): 571-578, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-29260317

RESUMO

Cystinosis is a rare autosomal-recessive lysosomal storage disease with high morbidity and mortality. It is caused by mutations in the CTNS gene that encodes the cystine transporter, cystinosin, which leads to lysosomal cystine accumulation. Patients with infantile nephropathic cystinosis, the most common and most severe clinical form of cystinosis, commonly present with renal Fanconi syndrome by 6-12 months of age, and without specific treatment, almost all will develop end-stage renal disease (ESRD) by 10-12 years of age. Early corneal cystine crystal deposition is a hallmark of the disease. Cystinosis also presents with gastrointestinal symptoms (e.g., vomiting, decreased appetite, and feeding difficulties) and severe growth retardation and may affect several other organs over time, including the eye, thyroid gland, gonads, pancreas, muscles, bone marrow, liver, nervous system, lungs, and bones. Cystine-depleting therapy with cysteamine orally is the only specific targeted therapy available for managing cystinosis and needs to be combined with cysteamine eye drops for corneal disease involvement. In patients with early treatment initiation and good compliance to therapy, long-term cysteamine treatment delays progression to ESRD, significantly improves growth, decreases the frequency and severity of extrarenal complications, and is associated with extended life expectancy. Therefore, early diagnosis of cystinosis and adequate life-long treatment with cysteamine are essential for preventing end-organ damage and improving the overall prognosis in these patients.


Assuntos
Cisteamina/administração & dosagem , Eliminadores de Cistina/administração & dosagem , Cistinose/tratamento farmacológico , Sistemas de Transporte de Aminoácidos Neutros/genética , Cisteamina/efeitos adversos , Eliminadores de Cistina/efeitos adversos , Cistinose/complicações , Cistinose/diagnóstico , Cistinose/genética , Progressão da Doença , Esquema de Medicação , Predisposição Genética para Doença , Humanos , Mutação , Fatores de Tempo , Resultado do Tratamento
5.
Nephron ; 141(2): 133-146, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30554218

RESUMO

Mutations in the CTNS gene encoding the lysosomal membrane cystine transporter cystinosin are the cause of cystinosis, an autosomal recessive lysosomal storage disease. More than 140 CTNS mutations have been reported worldwide. Recent studies have discovered that cystinosin exerts other key cellular functions beyond cystine transport such as regulation of oxidative state, lysosomal dynamics and autophagy. Here, we review the different mutations described in the CTNS gene and the geographical distribution of incidence. In addition, the characteristics of the various mutations in relation to the functions of cystinosin needs to be further elucidated. In this review, we highlight the functional consequences of the different mutations in correlation with the clinical phenotypes. Moreover, we propose how this understanding would be fundamental for the development of new technologies through targeted gene therapy, holding promises for a possible cure of the kidney and extra-renal phenotypes of cystinosis.


Assuntos
Sistemas de Transporte de Aminoácidos Neutros/genética , Cistinose/genética , Reparo do DNA , Mutação , Animais , Cistinose/epidemiologia , Modelos Animais de Doenças , Genótipo , Geografia , Humanos , Incidência , Fenótipo
6.
Pediatr Nephrol ; 34(5): 873-881, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30413946

RESUMO

BACKGROUND: Cystinosis is an ultrarare disorder caused by mutations of the cystinosin (CTNS) gene, encoding a cystine-selective efflux channel in the lysosomes of all cells of the body. Oral therapy with cysteamine reduces intralysosomal cystine accumulation and slows organ deterioration but cannot reverse renal Fanconi syndrome nor prevent the eventual need for renal transplantation. A definitive therapeutic remains elusive. About 15% of cystinosis patients worldwide carry one or more nonsense mutations that halt translation of the CTNS protein. Aminoglycosides such as geneticin (G418) can bind to the mammalian ribosome, relax translational fidelity, and permit readthrough of premature termination codons to produce full-length protein. METHODS: To ascertain whether aminoglycosides permit readthrough of the most common CTNS nonsense mutation, W138X, we studied the effect of G418 on patient fibroblasts. RESULTS: G418 treatment induced translational readthrough of CTNSW138X constructs transfected into HEK293 cells and expression of full-length endogenous CTNS protein in homozygous W138X fibroblasts. CONCLUSIONS: Reduction in intracellular cystine indicates that the CTNS protein produced is functional as a cystine transporter. Interestingly, similar effects were seen even in W138X compound heterozygotes. These studies establish proof-of-principle for the potential of aminoglycosides to treat cystinosis and possibly other monogenic diseases caused by nonsense mutations.


Assuntos
Sistemas de Transporte de Aminoácidos Neutros/genética , Cistinose/tratamento farmacológico , Fibroblastos/efeitos dos fármacos , Gentamicinas/farmacologia , Terminação Traducional da Cadeia Peptídica/efeitos dos fármacos , Códon sem Sentido , Cistina/metabolismo , Cistinose/genética , Fibroblastos/metabolismo , Vetores Genéticos/genética , Gentamicinas/uso terapêutico , Células HEK293 , Humanos , Terminação Traducional da Cadeia Peptídica/genética , Plasmídeos/genética , RNA Mensageiro/análise , Proteínas Recombinantes/genética , Transfecção
7.
Int J Mol Sci ; 21(1)2019 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-31888107

RESUMO

Nephropathic cystinosis is a rare lysosomal storage disorder caused by mutations in CTNS gene leading to Fanconi syndrome. Independent studies reported defective clearance of damaged mitochondria and mitochondrial fragmentation in cystinosis. Proteins involved in the mitochondrial dynamics and the mitochondrial ultrastructure were analyzed in CTNS-/- cells treated with cysteamine, the only drug currently used in the therapy for cystinosis but ineffective to treat Fanconi syndrome. CTNS-/- cells showed an overexpression of parkin associated with deregulation of ubiquitination of mitofusin 2 and fission 1 proteins, an altered proteolytic processing of optic atrophy 1 (OPA1), and a decreased OPA1 oligomerization. According to molecular findings, the analysis of electron microscopy images showed a decrease of mitochondrial cristae number and an increase of cristae lumen and cristae junction width. Cysteamine treatment restored the fission 1 ubiquitination, the mitochondrial size, number and lumen of cristae, but had no effect on cristae junction width, making CTNS-/- tubular cells more susceptible to apoptotic stimuli.


Assuntos
Sistemas de Transporte de Aminoácidos Neutros/genética , Cisteamina/farmacologia , Cistinose/genética , Mitocôndrias/metabolismo , Células Cultivadas , Cistinose/metabolismo , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , GTP Fosfo-Hidrolases/metabolismo , Humanos , Túbulos Renais Proximais/citologia , Túbulos Renais Proximais/efeitos dos fármacos , Túbulos Renais Proximais/metabolismo , Proteínas de Membrana/metabolismo , Mitocôndrias/efeitos dos fármacos , Dinâmica Mitocondrial/efeitos dos fármacos , Proteínas Mitocondriais/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação
8.
Am J Transplant ; 18(11): 2823-2828, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30030899

RESUMO

Cystinosis is an autosomal recessive lysosomal storage disorder characterized by the defective transport of the amino acid cystine out of the lysosome due to a deficiency of cystinosin, the lysosomal cystine transporter. Patients have lysosomal cystine accumulation in various tissues, leading to cellular stress and damage, particularly in the kidney, cornea, and other extrarenal tissues. Cysteamine, a cystine-depleting agent, improves survival and delays the progression of disease, but it does not prevent the development of either renal failure or extrarenal complications. Furthermore, the drug has severe adverse effects that significantly reduce patient compliance. Allogeneic hematopoietic stem cell transplantation (HSCT) is currently established as a therapeutic option for many inborn errors of metabolism, where the main pathologic driving factor is an enzyme deficiency. Recent studies in the cystinosis mouse-model suggested that HSCT could be a curative treatment alternative to cysteamine therapy. We treated a 16-year-old boy who had infantile cystinosis and side effects of cysteamine therapy with HSCT. We were able to demonstrate successful transfer of the wild-type cystinosin protein and CTNS mRNA to nonhematological epithelial cells in the recipient, as well as a decrease in the tissue cystine-crystal burden. This is the first report of allogeneic HSCT in a patient with cystinosis, the prototype of lysosomal membrane-transporter disorders.


Assuntos
Sistemas de Transporte de Aminoácidos Neutros/administração & dosagem , Cistinose/terapia , Células Epiteliais/metabolismo , Transplante de Células-Tronco Hematopoéticas , Adolescente , Sistemas de Transporte de Aminoácidos Neutros/genética , Sistemas de Transporte de Aminoácidos Neutros/metabolismo , Cistinose/genética , Humanos , Masculino , Mutação , Prognóstico , Transplante Homólogo
9.
Rev Med Chil ; 146(1): 111-115, 2018 Jan.
Artigo em Espanhol | MEDLINE | ID: mdl-29806685

RESUMO

Nephropatic cystinosis (NC) is a rare disease associated with pathogenic variants in the CTNS gene, with a common variant that consists of a 57kb-deletion involving CTNS. Patients with NC that are treated with cysteamine improve their life quality and expectancy. We report a 12-month-old girl with a poor growth rate since the 4th month of life. She was admitted to the Hospital with acute kidney injury, severe dehydration and metabolic acidosis. She was treated with volume restorative and bicarbonate. Proximal tubulopathy and Fanconi's syndrome was diagnosed. Medical treatment improved renal function that was stabilized in stage 4 chronic kidney disease (CKD). Since infantile NC was suspected, CTNS genetic analysis was considered. Genomic DNA was isolated from peripheral blood to perform PCR for exons 3-12 in CTNS gene and for the specific 57kb-deletion PCR. Afterwards, variant segregation analysis was performed in the familiar trio. The genetic analysis showed that the patient was homozygous for the common 57kb-deletion encompassing CTNS that had been inherited from her asymptomatic heterozygous parents. The molecular confirmation allowed genetic counselling for parents and facilitated the access to cysteamine. Oral treatment with cysteamine resulted in improvement of renal function to CKD stage 3. After 16 months of treatment the patient shows metabolic stability and mild recovery of height. Ophthalmologic follow-up detected ocular cystine crystals 12 months after diagnosis, starting cysteamine drops.


Assuntos
Cistinose/diagnóstico , Cistinose/genética , Cisteamina/uso terapêutico , Eliminadores de Cistina/uso terapêutico , Cistinose/tratamento farmacológico , Feminino , Humanos , Lactente , Reação em Cadeia da Polimerase , Diagnóstico Pré-Natal
10.
Iran J Kidney Dis ; 12(1): 61-63, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29421779

RESUMO

Cystinosis is a rare autosomal recessive disorder resulting from defective lysosomal transport of cystine due to mutations in the cystinosin lysosomal cystine transporter (CTNS) gene. The clinical phenotype of nephropathic cystinosis is characterized by renal tubular Fanconi syndrome and development of end-stage renal disease during the first decade. Although metabolic acidosis is the classically prominent finding of the disease, a few cases may present with hypokalemic metabolic alkalosis mimicking Bartter syndrome. Bartter-like presentation may lead to delay in diagnosis and initiation of specific treatment for cystinosis. We report a case of a 6-year-old girl initially presenting with the features of Bartter syndrome that was diagnosed 2 years later with nephropathic cystinosis and a novel CTNS mutation.


Assuntos
Sistemas de Transporte de Aminoácidos Neutros/genética , Síndrome de Bartter/diagnóstico , Cistinose/diagnóstico , Cistinose/genética , Mutação , Alcalose/etiologia , Criança , Cistinose/complicações , Cistinose/terapia , Análise Mutacional de DNA , Diagnóstico Diferencial , Progressão da Doença , Feminino , Predisposição Genética para Doença , Humanos , Hipopotassemia/etiologia , Falência Renal Crônica/etiologia , Diálise Peritoneal , Fenótipo , Valor Preditivo dos Testes
11.
BMC Nephrol ; 18(1): 300, 2017 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-28950840

RESUMO

BACKGROUND: Cystinosis is a rare autosomal recessive lysosomal disorder characterized by the accumulation of cystine in lysosomes. Cystinosis is much rarer in Asian than Caucasian populations. There are only 14 patients have with cystinosis alive in Japan. Most cystinosis is the nephropathic infantile form, as indicated by its apparent and severe clinical manifestations, including renal and ocular symptoms. Patients with the nephropathic juvenile form account for 5% of those with cystinosis. Their diagnosis is frequently delayed and difficult because of slower progression to end-stage renal disease and fewer cystine crystals in the cornea. Molecular analysis and a cysteine-binding protein assay should be performed when patients with proximal tubulopathy of an unknown origin are encountered. CASE PRESENTATION: A 12-year-old boy had been suffering from Fanconi syndrome since he was 3 years old. He was only recently diagnosed despite repeated ophthalmological examinations. Corneal cystine crystals were found when he was 12 years old, and he was diagnosed with cystinosis by high free cystine content in granulocytes (6.36 nmol half-cystine/mg protein, normal: <0.15). Analysis of the CTNS gene showed two novel heterozygous single nucleotide substitutions of c.329G > C and c.329 + 2 T > C. Both were splicing site variants causing exon 6 skipping proven by transcript analysis, although the functional prediction site showed c.329G > C, p.(Gly110Ala) as a benign missense substitution. The patient's estimated glomerular filtration rate was 66.8 mL/min/1.73 m2. He was immediately treated with cysteamine after diagnosis. CONCLUSIONS: Even if no ophthalmological abnormalities are present, nephropathic juvenile cystinosis should be suspected in children with Fanconi syndrome. Transcript analysis was useful to detect pathogenic splicing variants in this patient.


Assuntos
Cistinose/diagnóstico , Cistinose/genética , Síndrome de Fanconi/diagnóstico , Síndrome de Fanconi/genética , Síndrome Nefrótica/diagnóstico , Síndrome Nefrótica/genética , Criança , Cisteamina/uso terapêutico , Cistinose/tratamento farmacológico , Síndrome de Fanconi/tratamento farmacológico , Humanos , Masculino , Síndrome Nefrótica/tratamento farmacológico , Microscopia com Lâmpada de Fenda/métodos
12.
J Inherit Metab Dis ; 40(4): 555-567, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28643139

RESUMO

Cysteamine is a small aminothiol endogenously derived from coenzyme A degradation. For some decades, synthetic cysteamine has been employed for the treatment of cystinosis, and new uses of the drug continue to emerge. In this review, we discuss the role of cysteamine in cellular and extracellular homeostasis and focus on the potential use of aminothiols to reconstitute the function of proteins harboring arginine (Arg) to cysteine (Cys) mutations, via repair of the Cys residue into a moiety that introduces an amino group, as seen in basic amino acid residues Lys and Arg. Cysteamine has been utilized in vitro and ex vivo in four different genetic disorders, and thus provides "proof of principle" that aminothiols can modify Cys residues. Other aminothiols such as mercaptoethylguanidine (MEG) with closer structural resemblance to the guanidinium moiety of Arg are under examination for their predicted enhanced capacity to reconstitute loss of function. Although the use of aminothiols holds clinical potential, more studies are required to refine specificity and treatment design. The efficacy of aminothiols to target proteins may vary substantially depending on their specific extracellular and intracellular locations. Redox potential, pH, and specific aminothiol abundance in each physiological compartment are expected to influence the reactivity and turnover of cysteamine and analogous drugs. Upcoming research will require the use of suitable cell and animal models featuring Arg to Cys mutations. Since, in general, Arg to Cys changes comprise about 8% of missense mutations, repair of this specific mutation may provide promising avenues for many genetic diseases.


Assuntos
Arginina/química , Cisteamina/química , Cisteína/química , Cistinose/terapia , Mutação , Animais , Apolipoproteína E3/metabolismo , Argininossuccinato Liase/metabolismo , Cistationina beta-Sintase/metabolismo , Cistinose/genética , Cistinose/metabolismo , Homeostase , Humanos , Concentração de Íons de Hidrogênio , Conformação Molecular , Mutação de Sentido Incorreto , Oxirredução , Compostos de Sulfidrila/química , Tromboplastina/metabolismo
13.
Neuromuscul Disord ; 27(9): 873-878, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28629674

RESUMO

Nephropathic cystinosis is an autosomal recessive lysosomal disease in which cystine cannot exit the lysosome to complete its degradation in the cytoplasm, thus accumulating in tissues. Some patients develop a distal myopathy involving mainly hand muscles. Myopathology descriptions from only 5 patients are available in the literature. We present a comprehensive clinical, pathological and genetic description of 3 patients from 2 families with nephropathic cystinosis. Intrafamiliar variability was detected in one family in which one sibling developed a severe distal myopathy while the other sibling did not show any signs of skeletal muscle involvement. One of the patients was on treatment with Cysteamine for over 12 years but still developed the usual complications of nephropathic cystinosis in his twenties. Novel pathological findings consisting in sarcoplasmic deposits reactive for slow myosin were identified. Three previously known and one novel mutation are reported. Nephropathic cystinosis should be included in the differential diagnosis of distal myopathies in those with early renal failure. Novel clinical and pathological features are reported here contributing to the characterization of the muscle involvement in nephropathic cystinosis.


Assuntos
Sistemas de Transporte de Aminoácidos Neutros/genética , Cistinose , Miopatias Distais , Miosinas Cardíacas/genética , Cistina/metabolismo , Cistinose/complicações , Cistinose/genética , Cistinose/patologia , Miopatias Distais/etiologia , Miopatias Distais/genética , Miopatias Distais/patologia , Saúde da Família , Feminino , Humanos , Masculino , Microscopia Eletrônica , Pessoa de Meia-Idade , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Músculo Esquelético/ultraestrutura , Mutação/genética , Cadeias Pesadas de Miosina/genética , Miosinas/metabolismo , Adulto Jovem
14.
Nefrología (Madr.) ; 37(3): 301-310, mayo-jun. 2017. ilus, tab
Artigo em Inglês | IBECS | ID: ibc-164644

RESUMO

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 CTNSexon 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 (AU)


Objetivo: En este informe, documentamos las mutaciones del gen CTNS de 28 pacientes iraníes con cistinosis nefropática y una edad de 1-17 años. En un principio, todos presentaron retraso del desarrollo, poliuria y polidipsia. Métodos: En primer lugar, un nefrólogo pediátrico diagnosticó la cistinosis y luego los pacientes fueron trasladados a la clínica genética de la Universidad de Ciencias Médicas de Irán para consulta y análisis molecular, que incluía la multiplicación por reacción en cadena de la polimerasa (PCR), para determinar la existencia o ausencia de la deleción del fundador del 57kb en el CTNS, seguida por la secuenciación directa de los exones de codificación del CTNS. Resultados: La deleción frecuente del 57kb no se observó en ninguno de los 28 pacientes iraníes. En 14 de los 28 pacientes (50%) se observaron mutaciones en los exones 6 y 7. No se detectó ninguna mutación en el exón 5 y solo un paciente (3,6%) con cistinosis mostró una deleción del 4pb, anteriormente comunicada, en el exón 3 del CTNS. De ellos, 4 pacientes (14,3%) tenían una mutación anteriormente comunicada (c.969C > A; p.N323K) en el exón 11 y 5 (18%) tenían nuevas deleciones homocigóticas en el exón 6 que produjeron el vaciamiento prematuro de la proteína. Entre estas deleciones se puede citar c.323delA; p.Q108RfsX10 en 3 personas y c.257-258delCT; p.S86FfsX37 en 2 casos. Otras mutaciones con desplazamiento del marco de lectura fueron todas nuevas deleciones/inserciones de un par de bases únicas homocigóticas, incluyendo una en el exón 9 del CTNS(c.661insT; p.V221CfsX6) y 4 (14,3%) en el exón 4, es decir, c.92insG; p.V31GfsX28 en 2 y c.120delC; p.T40TfsX10 en 2. En total, en nuestros pacientes se identificaron 8 mutaciones anteriormente comunicadas y 8 mutaciones nuevas. La única mutación del sitio de empalme detectada (IVS3-2A>C) estaba asociada con la mutación de inserción en el exón 9. Conclusión: Este estudio, el primer análisis genético molecular de pacientes iraníes con cistinosis nefropática de carácter no específicamente étnico, puede servir como guía para el diagnóstico molecular de la cistinosis en Irán (AU)


Assuntos
Humanos , Masculino , Feminino , Lactente , Pré-Escolar , Criança , Adolescente , Cistinose/genética , Nefropatias/genética , Análise Citogenética/métodos , Predisposição Genética para Doença , Irã (Geográfico)/epidemiologia , Reação em Cadeia da Polimerase , Mutação/genética
15.
Cardiol Young ; 27(7): 1434-1436, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28490397

RESUMO

Cystinosis is a rare, autosomal-recessive genetic disorder. The kidneys are commonly involved, as there is cystinosin protein malfunction, and nephropathic cystinosis ensues. Although cardiac and vascular involvements are rare, we describe a unique case of aortic dissection in a 25-year-old female with cystinosis. We discuss the possible aetiologies of aortic dissection in this condition.


Assuntos
Aneurisma Dissecante/complicações , Aneurisma Aórtico/complicações , Cistinose/complicações , Adulto , Aneurisma Dissecante/diagnóstico por imagem , Aneurisma Dissecante/etiologia , Aneurisma Dissecante/cirurgia , Aneurisma Aórtico/diagnóstico por imagem , Aneurisma Aórtico/cirurgia , Cistinose/genética , Ecocardiografia , Feminino , Humanos
16.
J Biol Chem ; 292(25): 10328-10346, 2017 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-28465352

RESUMO

The lysosomal storage disease cystinosis, caused by cystinosin deficiency, is characterized by cell malfunction, tissue failure, and progressive renal injury despite cystine-depletion therapies. Cystinosis is associated with defects in chaperone-mediated autophagy (CMA), but the molecular mechanisms are incompletely understood. Here, we show CMA substrate accumulation in cystinotic kidney proximal tubule cells. We also found mislocalization of the CMA lysosomal receptor LAMP2A and impaired substrate translocation into the lysosome caused by defective CMA in cystinosis. The impaired LAMP2A trafficking and localization were rescued either by the expression of wild-type cystinosin or by the disease-associated point mutant CTNS-K280R, which has no cystine transporter activity. Defective LAMP2A trafficking in cystinosis was found to associate with decreased expression of the small GTPase Rab11 and the Rab7 effector RILP. Defective Rab11 trafficking in cystinosis was rescued by treatment with small-molecule CMA activators. RILP expression was restored by up-regulation of the transcription factor EB (TFEB), which was down-regulated in cystinosis. Although LAMP2A expression is independent of TFEB, TFEB up-regulation corrected lysosome distribution and lysosomal LAMP2A localization in Ctns-/- cells but not Rab11 defects. The up-regulation of Rab11, Rab7, or RILP, but not its truncated form RILP-C33, rescued LAMP2A-defective trafficking in cystinosis, whereas dominant-negative Rab11 or Rab7 impaired LAMP2A trafficking. Treatment of cystinotic cells with a CMA activator increased LAMP2A localization at the lysosome and increased cell survival. Altogether, we show that LAMP2A trafficking is regulated by cystinosin, Rab11, and RILP and that CMA up-regulation is a potential clinically relevant mechanism to increase cell survival in cystinosis.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Sistemas de Transporte de Aminoácidos Neutros/metabolismo , Cistinose/metabolismo , Proteína 2 de Membrana Associada ao Lisossomo/metabolismo , Lisossomos/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Substituição de Aminoácidos , Sistemas de Transporte de Aminoácidos Neutros/genética , Animais , Cistinose/genética , Cistinose/patologia , Ativadores de Enzimas/farmacologia , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Regulação Enzimológica da Expressão Gênica/genética , Proteína 2 de Membrana Associada ao Lisossomo/genética , Lisossomos/genética , Camundongos , Camundongos Knockout , Mutação Puntual , Transporte Proteico/genética , Proteínas rab de Ligação ao GTP/biossíntese , Proteínas rab de Ligação ao GTP/genética
18.
Sci Rep ; 7: 42583, 2017 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-28198397

RESUMO

The human ubiquitous protein cystinosin is responsible for transporting the disulphide amino acid cystine from the lysosomal compartment into the cytosol. In humans, Pathogenic mutations of CTNS lead to defective cystinosin function, intralysosomal cystine accumulation and the development of cystinosis. Kidneys are initially affected with generalized proximal tubular dysfunction (renal Fanconi syndrome), then the disease rapidly affects glomeruli and progresses towards end stage renal failure and multiple organ dysfunction. Animal models of cystinosis are limited, with only a Ctns knockout mouse reported, showing cystine accumulation and late signs of tubular dysfunction but lacking the glomerular phenotype. We established and characterized a mutant zebrafish model with a homozygous nonsense mutation (c.706 C > T; p.Q236X) in exon 8 of ctns. Cystinotic mutant larvae showed cystine accumulation, delayed development, and signs of pronephric glomerular and tubular dysfunction mimicking the early phenotype of human cystinotic patients. Furthermore, cystinotic larvae showed a significantly increased rate of apoptosis that could be ameliorated with cysteamine, the human cystine depleting therapy. Our data demonstrate that, ctns gene is essential for zebrafish pronephric podocyte and proximal tubular function and that the ctns-mutant can be used for studying the disease pathogenic mechanisms and for testing novel therapies for cystinosis.


Assuntos
Sistemas de Transporte de Aminoácidos Neutros/genética , Sistemas de Transporte de Aminoácidos Neutros/metabolismo , Cistinose/genética , Cistinose/metabolismo , Glomérulos Renais/metabolismo , Túbulos Renais Proximais/metabolismo , Mutação , Sequência de Aminoácidos , Animais , Apoptose/genética , Cistina/metabolismo , Cistinose/mortalidade , Cistinose/patologia , Modelos Animais de Doenças , Técnicas de Inativação de Genes , Taxa de Filtração Glomerular , Humanos , Glomérulos Renais/patologia , Glomérulos Renais/ultraestrutura , Túbulos Renais Proximais/patologia , Túbulos Renais Proximais/ultraestrutura , Locomoção , Lisossomos/metabolismo , Fenótipo , Podócitos/metabolismo , Podócitos/patologia , Podócitos/ultraestrutura , Peixe-Zebra
19.
Nefrologia ; 37(3): 301-310, 2017.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-28238446

RESUMO

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.


Assuntos
Sistemas de Transporte de Aminoácidos Neutros/genética , Cistinose/genética , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Irã (Geográfico) , Masculino , Mutação
20.
Pediatr Res ; 81(1-1): 113-119, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27656773

RESUMO

BACKGROUND: Nephropathic cystinosis is a lysosomal storage disease that is caused by mutations in the CTNS gene encoding a cystine/proton symporter cystinosin and an isoform cystinosin-LKG which is generated by an alternative splicing of exon 12. We have investigated the physiological role of the cystinosin-LKG that is widely expressed in epithelial tissues. METHODS: We have analyzed the intracellular localization and the function of the cystinosin-LKG conjugated with DsRed (cystinosin-LKG-RFP) in Madin-Darby canine kidney cells (MDCK II) and in proximal tubular epithelial cells carrying a deletion of the CTNS gene (cystinotic PTEC), respectively. RESULTS: Cystinosin-LKG-RFP colocalized with markers of lysosomes, late endosomes and was also expressed on the apical surface of polarized MDCK II cells. Moreover, immune-electron microscopy images of MDCK II cells overexpressing cystinosin-LKG-RFP showed stacked lamellar membranes inside perinuclear lysosomal structures. To study the role of LKG-isoform, we have investigated cystine accumulation and apoptosis that have been described in cystinotic cells. Cystinosin-LKG decreased cystine levels by approximately 10-fold similarly to cystinosin-RFP. The levels of TNFα- and actinomycin D-inducted apoptosis dropped in cystinotic cells expressing LKG-isoform. This effect was also similar to the main isoform. CONCLUSION: Our results suggest that cystinosin-LKG and cystinosin move similar functional activities in cells.


Assuntos
Sistemas de Transporte de Aminoácidos Neutros/metabolismo , Cistina/metabolismo , Cistinose/metabolismo , Cistinose/patologia , Processamento Alternativo , Sistemas de Transporte de Aminoácidos Neutros/química , Sistemas de Transporte de Aminoácidos Neutros/genética , Animais , Apoptose , Células Cultivadas , Cistinose/genética , Cães , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Humanos , Túbulos Renais Proximais/metabolismo , Túbulos Renais Proximais/patologia , Lisossomos/metabolismo , Células Madin Darby de Rim Canino , Microscopia Eletrônica de Transmissão , Mutação , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
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