The genetics of cystinuria - an update and critical reevaluation.

PURPOSE OF REVIEW: We aimed to critically evaluate how the establishment of genotype-based treatment for cystinuria has been hampered due to the large number of variants of unknown significance (VUS) within the disease causing genes as well as challenges in accessing a large enough sample size for systematic analysis of endpoint parameters that truly reflect disease severity. This review further discusses how to overcome these hurdles with the establishment of a cystinuria-specific refinement of the current American College of Medical Genetics and Genomics (ACMG)-criteria of variant interpretation. RECENT FINDINGS: Novel tools such as AlphaMissense combined with the establishment of a refined ACMG criterion will play a significant role in classifying VUS within the responsible disease genes SLC3A1 (rBAT) and SLC7A9 (BAT1). This will also be essential in elucidating the role of promising candidate genes, such as SLC7A13 (AGT1), which have been derived from murine model systems and still need further research to determine if they are involved in human cystinuria. SUMMARY: Cystinuria was one of the first disorders to receive a gene-based classification, nonetheless, the clinically actionable implications of genetic diagnostics is still minor. This is due to poorly characterized genotype-phenotype correlations which results in a lack of individualized (genotype-) based management and metaphylaxis.

Ureteroscopic management in cystinuric patients: long-term results from a tertiary care referral center.

OBJECTIVE: To evaluate long-term surgical and functional outcomes of cystinuric patients exclusively treated with Ureteroscopy (URS). METHODS: Data from patients treated for cystine stones at a single academic center were retrospectively analyzed. The management protocol consisted of (i) treating symptomatic or > 7 mm stones, (ii) multi-staged URS for voluminous stones, (iii) referring patients to a dedicated nephrological clinic. The eGFR was calculated according to the MDRD formula. CKD category was assessed according to the NKF classification. Relevant CKD was defined as CKD category ≥ 3a. Descriptive statistics were used to analyze the cohort data. RESULTS: Data from 46 cystinuric patients treated with 332 URS were available. Median age at diagnosis and at first URS in our center were 18 and 32 years, respectively. Median follow-up was 101 months. Median number of URS and recurrences per patient were 6 and 2, respectively. The median interval between the first and the last available creatinine level was 64 months. Median first and last eGFR were 72 and 74 mL/min, respectively. Overall, 83% of patients had stable or improved renal function within the study period. Ureteral stricture occurred in 3 (6.5%) patients. CONCLUSIONS: Cystinuria requires intensive endoscopic management. Most patients treated with URS have stable or improved renal function within a long-term follow-up. CKD is a not neglectable event that potentially occurs at an early stage of life. Current findings should be considered for the surgical management of cystinuric patients.

Covalent post-synthetic modification of MOFs as a fluorescent sensor for the efficient detection of the biomarker of cystinuria.

Cystinuria is a genetic disorder, and in severe cases, it might lead to kidney failure. As an important biomarker for cystinuria, the level of arginine (Arg) in urine is a vital indicator for cystinuria screening. Therefore, it is urgently needed to detect Arg with high selectivity and sensitivity. In this work, a boric acid functionalized Zr-based metal-organic framework UiO-PhbA is prepared by grafting phenylboronic acid on UiO-66-NH2 through a Schiff base reaction using a covalent post-synthesis modification (CPSM) strategy. The prepared UiO-PhbA exhibits a sensitive and specific fluorescence "turn-on" response to Arg and can be exploited to detect Arg in human serum and urine samples with a broad linear range of 0.6-350 µM and low limit of detection (LOD) of 18.45 nM. This study provides a new and reliable rapid screening protocol for sulfite oxidase deficiency-related diseases.

Exploring the Contribution of the Transporter AGT1/rBAT in Cystinuria Progression: Insights from Mouse Models and a Retrospective Cohort Study.

More than 20 years have passed since the identification of SLC3A1 and SLC7A9 as causative genes for cystinuria. However, cystinuria patients exhibit significant variability in the age of lithiasis onset, recurrence, and response to treatment, suggesting the presence of modulatory factors influencing cystinuria severity. In 2016, a second renal cystine transporter, AGT1, encoded by the SLC7A13 gene, was discovered. Although it was discarded as a causative gene for cystinuria, its possible effect as a modulatory gene remains unexplored. Thus, we analyzed its function in mouse models of cystinuria, screened the SLC7A13 gene in 34 patients with different lithiasic phenotypes, and functionally characterized the identified variants. Mice results showed that AGT1/rBAT may have a protective role against cystine lithiasis. In addition, among the four missense variants detected in patients, two exhibited a 25% impairment in AGT1/rBAT transport. However, no correlation between SLC7A13 genotypes and lithiasis phenotypes was observed in patients, probably because these variants were found in heterozygous states. In conclusion, our results, consistent with a previous study, suggest that AGT1/rBAT does not have a relevant effect on cystinuria patients, although an impact in patients carrying homozygous pathogenic variants cannot be discarded.

Cystinuria Complicated by Anuria From Bilateral Obstructing Stones Requiring Bilateral Mini Percutaneous Nephrolithotomy in a 22-Month-Old.

Pediatric nephrolithiasis is increasing in incidence and presents differently compared to adults. We report a case of nephrolithiasis in a pediatric patient, presenting with complaints of emesis, anuria, hematuria, and abdominal distension, leading to a diagnosis of bilateral obstructing cystine stones requiring bilateral percutaneous nephrolithotomy. Pediatric patients with anuria should be evaluated for bilateral nephrolithiasis as an etiology. Calculous anuria requires prompt recognition of the pathologic process and relief of the obstruction with close follow-up and supportive care until definitive stone management. Bilateral percutaneous nephrolithotomy can provide definitive surgical intervention without significant morbidity.

Novel compound heterozygous pathogenic variants in the SLC3A1 gene in a Chinese family with cystinuria.

BACKGROUND: Cystinuria is an autosomal recessive disorder characterized by a cystine transport deficiency in the renal tubules due to mutations in two genes: SLC3A1 and SLC7A9. Cystinuria can be classified into three forms based on the genotype: type A, due to mutations in the SLC3A1 gene; type B, due to mutations in the SLC7A9 gene; and type AB, due to mutations in both genes. METHODS: We report a 12-year-old boy from central China with cystine stones. He was from a non-consanguineous family that had no known history of genetic disease. A physical examination showed normal development and neurological behaviors. Whole-exome and Sanger sequencing were used to identify and verify the suspected pathogenic variants. RESULTS: The compound heterozygous variants c.898_905del (p.Arg301AlafsTer6) is located in exon5 and c.1898_1899insAT (p.Asp634LeufsTer46) is located in exon10 of SLC3A1 (NM_000341.4) were deemed responsible for type A cystinuria family. The variant c.898_905del was reported in a Japanese patient in 2000, and the variant c.1898_1899insAT is novel. CONCLUSION: A novel pathogenic heterozygous variant pair of the SLC3A1 gene was identified in a Chinese boy with type A cystinuria, enriching the mutational spectrum of the SLC3A1 gene. We attempted to find a pattern for the association between the genotype of SLC3A1 variants and the manifestations of cystinuria in patients with different onset ages. Our findings have important implications for genetic counseling and the early clinical diagnosis of cystinuria.

Cistinuria como causa de litiasis urinaria / Cystinuria as a cause of urolithiasis

La cistinuria es una enfermedad genética que provoca un defecto de reabsorción de cistina, causando como manifestación principal litiasis urinarias que pueden llegar a ser de gran tamaño. Es importante tratarla desde temprana edad porque puede comportar importantes comorbilidades. (AU)

Cystinuria is a genetic disease that causes impaired cystine reabsorption. Its main manifestation is urolithiasis, in some cases producing very large stones. It is important to treat it from an early age because it can lead to important comorbidities. (AU)

Cistinuria: la importancia del sedimento / Cystinuria: the importance of sediment

La cistinuria es causada por el exceso de un aminoácido llamado cistina (dímero del aminoácido cisteína) en la orina. Fue descrita por primera vez a principios del siglo XIX. Es una enfermedad metabólica congénita con un patrón de herencia autosómico recesivo, se caracteriza por un defecto en el transporte que afecta a determinados aminoácidos dibásicos: cistina, ornitina, lisina y arginina (COLA) en su reabsorción en el túbulo renal y tracto gastrointestinal; como resultado solo la cistina, debido a su gran insolubilidad en orinas ácidas por aumento de la excreción y sobresaturación en la orina, favorece la formación de cristales o precipitados formando cálculos. Presentamos un caso de cistinuria en un adulto que fue diagnosticado por los cristales encontrados en el sedimento urinario, después de hacer diagnóstico diferencial con los cristales de colesterol anhidro, con los que pueden confundirse

Cystinuria is caused by the excess of an amino acid called cystine (amino acid dimer cysteine), in the urine. It was first described at the beginning of the 19th century. It is a congenital metabolic disease with an autosomal recessive inheritance pattern. It is characterised by a defect in transport, which affects certain dibasic amino acids, cystine, ornithine, lysine, and arginine in its reabsorption into the renal tubule and gastrointestinal tract. As a result, only cystine (due to its great insolubility in acid urine owing to increased excretion and supersaturation in urine), promotes the formation of crystals or precipitates that form stones. The case is presented of an adult with cystinuria, who was diagnosed by the crystals found in the urinary sediment, after making a differential diagnosis with the crystals of anhydrous cholesterol, with which they can be confused

Reporte de un caso de Cistinuria: Uso de herramientas de diagnóstico a nivel nacional / Report of a case of cystinuria: Use of diagnostic tools at national level

La cistinuria es una enfermedad genética que se engloba dentro de alteraciones congénitas del transporte de aminoácidos con formación de cálculos en las vías urinarias, si bien es poco frecuente se caracteriza por su elevada recurrencia. En este trabajo presentamos el caso de una paciente de 34 años, con antecedentes de haber perdido un riñón por episodios anteriores de litiasis y con múltiples recidivas que es diagnosticada mediante la detección de cistina por espectroscopía infrarroja como componente único de 96 fragmentos de cálculos removidos mediante nefrolitotomía percutánea. La paciente fue evaluada laboratorialmente mediante el perfil metabólico y la cristaluria. Las indicaciones de tratamiento específicas incluyeron la administración de agentes alcalinizantes, régimen nutricional, y entrenamiento para control de pH urinario. Es importante señalar la agresividad de la litiasis de cistina con las consecuencias que puede tener la calidad de vida del paciente, y por tanto la importancia de contar con capacidades instaladas a nivel país para el diagnóstico y seguimiento de litiasis genéticas como la causada por la cistinuria(AU)

Cystinuria is a genetic disease that is included among congenital defects of renal amino acids transport that causes urinary stone formation. Although it is rare, it is characterized by its high recurrence. We present the case of a 34-year-old patient that lost one of her kidney because of recurrent episodes of lithiasis, and that was diagnosed by the detection of cystine with infrared spectroscopy as the sole component of 96 stone fragments removed by percutaneous nephrolithotomy. The patient was evaluated by metabolic profile and crystalluria. The specific treatment indications included the administration of alkalinizing agents, nutritional regimen, and training for personal measurement of urinary pH. This case highlights the aggressiveness of cystine stones with the consequences that may have on the quality of the patient life, and therefore the importance of having installed proper diagnostic capacities at national level to detect and monitor treatment efficacy in genetic lithiasis such as cystinuria(AU)

The impact of surgical intervention on renal function in cystinuria / O impacto da intervenção cirúrgica sobre a função renal na cistinúria

ABSTRACT Introduction: Cystinuria is an autosomal recessive disorder due to intestinal and renal transport defects in cystine and dibasic amino acids, which result in recurrent urolithiasis and surgical interventions. This study aimed to assess the impact of surgical interventions on renal function by analyzing estimated glomerular filtration rates. Methods: Thirteen pediatric patients with cystinuria, who were followed-up in a single tertiary institution between 2004 and 2016, were included in the study. Medical records were reviewed to collect data on clinical presentation of patients, urine parameters, stone formation, medical treatment, surgical intervention, stone recurrence after surgical procedure, stone analysis, ultrasonography, 99m-technetium dimercaptosuccinic acid (99mTc-DMSA) radionuclide imaging results, and follow-up time. Creatinine clearances estimated by modified Schwartz (eGFR) formula before and after surgery were used to assess renal function and compared statistically. Results: Nine patients (69.2%) had renal scarring which were detected with 99mTc-DMSA radionuclide imaging. In ten patients (76.9%), open surgical intervention for stones were needed during follow-up. Significant difference was not detected between eGFR before and after surgical intervention (mean 92 versus 106, p = 0.36). Nine of the patients (69.2%) were stone free in the last ultrasonographic examination. Relapses of stone after surgery were seen in 66.6% of patients who underwent surgical intervention. Conclusions: Surgical interventions for urinary stones are commonly required in patients with cystinuria. Renal scarring is a prevalent finding in cystinuric patients. Surgical interventions have no negative impact on eGFR in patients with cystinuria according to the present study.

RESUMO Introdução: A cistinúria é um distúrbio autossômico recessivo causado por defeitos de transporte intestinal e renal da cistina e aminoácidos dibásicos que resultam em urolitíase recorrente e necessidade de intervenção cirúrgica. O presente estudo teve por objetivo avaliar o impacto das intervenções cirúrgicas sobre a função renal por meio da análise da taxa de filtração glomerular estimada. Métodos: Treze pacientes pediátricos com cistinúria acompanhados em uma instituição terciária entre 2004 e 2016 foram incluídos no estudo. Os prontuários médicos foram analisados e utilizados como fonte de dados sobre a apresentação clínica dos pacientes, parâmetros urinários, formação de cálculos, tratamento clínico, intervenção cirúrgica, recidiva de cálculos após procedimento cirúrgico, análise de cálculos, ultrassonografia, resultados de imagens com ácido dimercaptossuccínico marcado com tecnécio metaestável (99mTc-DMSA) e tempo de seguimento. A depuração de creatinina estimada pela fórmula modificada de Schwartz (TFGe) antes e após a cirurgia foi utilizada para avaliar e comparar estatisticamente os níveis de função renal. Resultados: Nove pacientes (69,2%) apresentaram cicatrizes renais detectadas por exame de imagem com 99mTc-DMSA. Dez pacientes (76,9%) necessitaram intervenção cirúrgica aberta por cálculo renal durante o seguimento. Não foram detectadas diferenças significativas entre os valores de TFGe anteriores e posteriores à intervenção cirúrgica (média de 92 vs. 106, p = 0,36). Nove pacientes (69,2%) não apresentaram cálculos no último exame ultrassonográfico. Recidivas de cálculos renais após cirurgia foram observadas em 66,6% dos pacientes submetidos a cirurgia. Conclusões: Intervenções cirúrgicas relativas a cálculos renais são frequentemente necessárias em pacientes com cistinúria. Cicatrizes renais são um achado prevalente em pacientes com cistinúria. De acordo com o presente estudo, cirurgia não afeta negativamente a TFGe de pacientes com cistinúria.

Entrando en el manejo 2.0 de la cistinuria con una herramienta médica digital para monitorizar el pH de la orina: un estudio prospectivo y aleatorizado / Entering into 2.0 cystinuria management with a medical digital tool to monitor urine pH: A prospective, randomized study

Introducción y objetivos Las personas con cistinuria pueden experimentar eventos recurrentes de litiasis debido a la relativa insolubilidad de la cistina en el pH fisiológico de la orina, lo que resulta en deterioro de la función renal. El pHmetro Lit-Control® es un dispositivo médico que permite la automedición precisa del pH de la orina. El objetivo principal de este estudio fue comparar la usabilidad del pHmetro Lit-Control® con las tiras reactivas para la automonitorización domiciliaria del pH urinario por parte de pacientes con cistinuria, y su satisfacción general con cada herramienta.Pacientes y métodosSe incluyeron 28 pacientes (9 mujeres y 19 varones, de 19 a 76 años), que fueron asignados aleatoriamente a monitorizar su pH urinario con tiras reactivas (n=17) o el pHmetro Lit-Control® (n=11).ResultadosDespués de 6 meses de uso, la satisfacción con los 2 métodos fue similarmente alta, pero los pacientes calificaron (en una escala de 0 a 10) mejor el pHmetro en términos de facilidad de aprendizaje (media± DE, 8,11±0,60 vs. 7,06±1,18; p=0,038), facilidad de preparación (8,22±0,67 vs. 7,25±1,18; p=0,034) y facilidad de uso (8,22±0,67 vs. 7,25±1,39; p=0,062). En general, los pacientes no alcanzaron los objetivos de alcalinización (pH entre 7,0 y 8,0).ConclusionesEl pHmetro Lit-Control® demostró ser un dispositivo fácil de usar que puede facilitar el control del pH urinario en los pacientes con cistinuria. Queda justificado un estudio prospectivo para evaluar la correlación entre la monitorización del pH de la orina, una estrategia de tratamiento por objetivo y la recurrencia de los cálculos de cistina. (AU)

Background and objectives Individuals with cystinuria can experiment recurrent lithiasis events due to the relative insolubility of cystine at physiological urine pH, resulting in renal function decline. The Lit-Control® pH Meter is a medical device that accurately allows urine pH self-monitoring. The main objective of this study was to compare the usability of the Lit-Control® pH Meter with the reactive strips for self-monitoring of urinary pH at home by patients with cystinuria, and their overall satisfaction with each tool.Patients and methodsWe included 28 patients (9 females and 19 males, age 19-6 years), who were randomly assigned to monitor their urine pH with reactive strips (n=17) or the Lit-Control® pH Meter (n=11).ResultsAfter six months of use, the satisfaction with the two methods was similarly high, but the patients rated (0-10 scale) the pH meter better in terms of ease of learning (mean±SD, 8.11±0.60 vs. 7.06±1.18; P=.038), ease to prepare (8.22±0.67 vs. 7.25±1.18; P=0.034), and ease of use (8.22±0.67 vs. 7.25±1.39; P=.062). Overall, patients did not reach the alkalinization goals (pH between 7.0 and 8.0).ConclusionsThe Lit-Control® pH Meter demonstrated to be an easy-to-use device that can facilitate urinary pH control by cystinuric patients. A prospective study is warranted to assess the correlation between urine pH monitoring, a treat to target approach, and the recurrence of cystine stones. (AU)

Genotype and Phenotype Analysis in Pediatric Patients with Cystinuria

Cystinuria is an inherited disorder characterized by defective renal reabsorption of cystine and dibasic amino acids leading to nephrolithiasis. This study was conducted to analyze the genotypes and phenotypes of pediatric patients with cystinuria. Eight children from Seoul National University Hospital and Asan Medical Center presenting with cystinuria from January 2003 to June 2016 were retrospectively analyzed. Mutational studies were performed by direct sequencing. Two of the 8 were male and 6 were female. The median ages at onset and diagnosis were 1.5 (range, 0.3–13.6) and 2.6 (range, 0.7–16.7) years, respectively. The median followed up was 7.7 (range, 3.4–14.0) years. Mutational analyses were performed in 7 patients and revealed biallelic SLC3A1 mutations (AA genotype) in 4 patients, a single heterozygous SLC3A1 mutation (A- genotype) in 1 patient, biallelic SLC7A9 mutations (BB genotype) in 1 patient, and a single heterozygous SLC7A9 mutation (B- genotype) in 1 patient. Two of the mutations were novel. No genotype-phenotype correlations were observed, except for earlier onset age in patients with non-AA genotypes than in patients with the AA genotype. All patients suffered from recurrent attacks of symptomatic nephrolithiasis, which lead to urologic interventions. At the last follow-up, 3 patients had a mild-to-moderate degree of renal dysfunction. This is the first study of genotypic and phenotypic analyses of patients with cystinuria in Korea.

Cistinuria: la recurrencia de lo excepcional / Cystinuria: the recurrence of the exceptional

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Cuantificación de cistina en orina espontánea para la detección de cistinuria / Quantitation of urinary cystine for the detection of cystinuria / Determinagáo quantitativa de cistina urinaria para a detecgáo de cistinuria

La cistinuria es un error innato del metabolismo ocasionado por un defecto en el transporte renal de arginina, ornitina, lisina y cistina. La acumulación de este último aminoácido de baja solubilidad ocasiona episodios de urolitiasis característicos de la enfermedad. En el presente estudio se estandarizó un método espectrofotométrico confiable y de fácil ejecución para la determinación cuantitativa de cistina en orina espontánea. Se realizó el análisis en 184 muestras, correspondientes a 104 controles y 80 pacientes con urolitiasis. Con el objeto de validar el método y posteriormente establecer un rango de excreción normal en la población colombiana se evaluaron los siguientes parámetros: exactitud, precisión, linealidad y límite de detección. La técnica mostró coeficientes de variación intra e inter ensayos inferiores al 10% y una excelente linealidad, con un coeficiente r² entre concentraciones conocidas de cistina y absorbancia generada por el método de 0,998. Usando esta técnica se encontró un valor normal de excreción de 1,35 a 110,11 mg cistina/g creatinina. En cinco pacientes, de los 80 con nefrolitiasis, se hallaron valores elevados de cistina, compatibles con cistinuria. El método utilizado puede implementarse en cualquier laboratorio clínico para confirmar el diagnóstico de cistinuria e iniciar un tratamiento oportuno.

Cystinuria is an inborn error of metabolism, caused by a defect in renal tubular transport of the following aminoacids: arginine, ornithine, lysine and cystine. Accumulation of the latter poorly soluble aminoacid leads to the development of kidney stones, characteristic of the disease. In this study, an easy and dependable spectrophotometric method for the quantitative determination of urinary cystine was standardized. The analysis was performed on 184 samples from 104 controls and 80 patients with kidney stones. In order to validate the method and later establish a range of normal urinary cystine excretion in the Colombian population, the following parameters were evaluated: Accuracy, precision, linearity and lower limit of detection. The technique showed intra and intei assay coefficients of variation below 10%, and excellent linearity, with an R square (r²) coefficient between known cystine concentrations and absorbance generated by the method at 0.998. Using this technique, a normal urinary cystine excretion range of 1.35-110.11 mg cystine/g creatinine was found. Among the 80 patients with kidney stones, elevated urinary cystine levels were found in 5 of them, compatible with the presence of cystinuria. This method can be implemented in any clinical laboratory to confirm the diagnosis of cystinuria and provide opportune treatment.

A cistinúria é um erro inato do metabolismo, causado por um defeito no transporte tubular renal de ar-ginina, ornitina, lisina e cistina. A acumulagáo deste último aminoácido, pouco solúvel, provoca episodios de urolitíase, característicos da doenga. No presente estudo, foi padronizado um método espectrofotomé-trico confiável e de fácil execugáo para a determinagáo quantitativa de cistina em urina espontánea. A análise foi realizada em 184 amostras de 104 controles e 80 pacientes com urolitíase. A fim de validar o método e, posteriormente, estabelecer um intervalo de excregao normal na populagao colombiana, foram avaliados os seguintes parámetros: exatidáo, precisáo, linearidade e limite inferior de detecgáo. O método mostrou coeficientes de variagáo intra e inter ensaios inferiores a 10%, e excelente linearidade, com um coeficiente R quadrado (r²) entre concentragoes conhecidas de cistina e absorváncia gerada pelo método de 0,998. Com esta técnica, foi encontrado um valor normal de excregáo de 1,35-110,11 mg cistina/g de creatinina. Entre os 80 pacientes com urolitíase, foram encontrados níveis elevados de cistina em cinco deles, compatíveis com a presenga de cistinúria. Este método pode ser implementado em qualquer laboratorio clínico para confirmar o diagnóstico de cistinúria e proporcionar um tratamento oportuno.

Multimodal Treatments of Cystine Stones: An Observational, Retrospective Single-Center Analysis of 14 Cases

PURPOSE: To document the experiences of a single institution in evaluating the clinical courses and treatment outcomes of patients with cystine stones. MATERIALS AND METHODS: The clinical data of 14 patients with cystine stones who were treated at our institution from March 1994 to July 2012 were reviewed. These data included age at first visit, gender, family history, body mass index, presence of a single kidney, stone locations, stone burden, routine urinalysis, and culture. In addition, we also analyzed data on surgery, shock wave lithotripsy, medical treatment, stone recurrence or regrowth, and overall treatment success rates. RESULTS: The mean age of our patients at their first visit was 19.6+/-5.0 years, and eight patients were males. The median stone burden and mean urine pH before each surgery were 6.5 cm2 and 6.5+/-0.9, respectively. Two patients had a family history of cystine stones. Patients underwent surgery an average of 2.7 times. The median interval between surgeries was 27.3 months, and 1 open surgery, 12 percutaneous nephrolithotomies, and 25 ureterorenoscopies were performed. Potassium citrate or sodium bicarbonate was used in nine cases. D-Penicillamine was continuously used in three patients. Patients had an average incidence of 3.2 recurrences or regrowth of stones during the median follow-up period of 60.5 months. CONCLUSIONS: Patients with cystine stones have high recurrence or regrowth rates and relatively large stone burdens. Adequate treatment schedules must therefore be established in these cases to prevent possible deterioration of renal function.

A Case of Cystinuria with Multiple Renal Stones in an 8-month-old Girl

Cystinuria is an autosomal recessive disease characterized by impaired transport of cystine and dibasic amino acids in the proximal renal tubule, resulting in the formation of cystine stones. It is believed to account for about 1% of all kidney stones and up to 10% of pediatric stones. Here we report a case of cystinuria with multiple renal stones confirmed by genetic mutational analysis. An 8-month-old girl was admitted to AMC with persistent fever and multiple renal stones. A renal sonogram showed multiple stones at the right renal pelvis, right distal ureter, and left renal medullary portion. An approximately 1 cm renal stone was extracted spontaneously, and stone analysis revealed it to be composed entirely of cystine. Cystinuria was confirmed by increased urine dibasic amino acid levels, including cysteine, and genetic mutational analysis showed the patient to be a homozygote for the pathogenic c. 1820del (p.L607fs) of SLC3A1. Despite treatment with oral hydration and urinary alkalinization, and restricted intake of animal protein, the stones increased in size and number. The patient has since been treated with tiopronin.

Epidemiología de la litiasis en España: nuevos escenarios / Epidemiology of urinary lithiasis in Spain: New scenarios

La litiasis renal es una de las afecciones más comunes de la sociedad moderna, constituyendo un importante problema de salud que además asocia una gran carga económica. La naturaleza de la litiasis varía según la edad y el sexo, viéndose también influenciada por factores dietéticos, climáticos y de estilo de vida entre otros. A pesar de los avances que se han producido en el manejo de dicha patología, ésta continúa siendo una enfermedad con alta tasa de recurrencia. En los últimos años son varios los trabajos que hacen referencia a un aumento en su prevalencia sobre todo en países desarrollados. Dicho incremento parecer ser fundamentalmente debido a un cambio en los hábitos dietéticos y en el estilo de vida, si bien, otros factores tales como un aumento de las temperaturas o los flujos migratorios hacia grandes urbes podrían estar también relacionados. En el presente trabajo se discuten los principales factores que a día de hoy parecen influir en la epidemiología de la litiasis urinaria, así como en el citado aumento de su prevalencia

Renal lithiasis is one of the most common disorders in modern society, constituting an important health problem that associates a great economic burden. The nature of stone disease varies according to age and sex, being also influenced by dietary and lifestyle factors, and climatic variations among others. In spite of the advances made in the management of this pathology, it continues being a disease with a high recurrence rate. In recent years, several studies have pointed out that its prevalence is rising especially in developed countries. This increase seems to be fundamentally due to changes in dietary habits and lifestyle, although other factors such as migratory flows from rural areas to major cities, and a rise in global temperatures may also be involved. In the present article, we discuss the main factors that seem to influence today the epidemiology of urinary litiasis, as well as the aforementioned increase of prevalence

Hiperecogenicidad prenatal del colon como signo precoz de cistinuria / No disponible

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Cistinuria: diagnóstico y aproximación terapéutica / Cystinuria: diagnosis and therapeutic approach

La cistinuria es una aminoaciduria debida a un transporte defectuoso de cistina y de aminoácidos dibásicos (arginina, ornitina, y lisina) en la membrana apical del epitelio intestinal y túbulo proximal renal. El resultado es una ausencia de reabsorción de cistina en el túbulo proximal renal produciendo un exceso de cistina en orina y con la consiguiente formación de cálculos renales. Los cálculos de cistina son muy difíciles de eliminar por litotricia a diferencia del resto de cálculos. Por lo tanto, debería de llevarse a cabo una terapia no invasiva para prevenir la recidiva en la formación de cálculos. Esta terapia estaría basada en una alta ingesta de líquidos, alcalinización de la orina, y empleo de agentes quelantes. A la hora de preservar la función renal es necesaria la combinación de estas tres medidas terapéuticas tanto para disminuir la recurrencia como la morbilidad de la enfermedad (AU)

Cystinuria is an aminoaciduria due to the impairment of transport of cystine and dibasic amino acids (arginine, ornithine, and lysine) in the apical membrane of the intestinal epithelium and proximal renal tubule. The result is an absence of cystine reabsorption in the renal tubule producing an excess of cystine in urine and stone formation. Unlike the other stones, cystinestones are very difficult to eliminate with lithotripsy. Non invasive therapy should therefore be used to prevent relapse in stone formation. This therapy is based on the use of high fluid in take, urine alkalinization, and chelating agents. In order to preserve renal function, a combination of these three therapeutic measures is necessary to produce a low recurrence and morbidity of the disease (AU)

Penicillamine-induced Elastosis Perforans Serpiginosa and Cutis Laxa in a Patient with Wilson's Disease

Elastosis perforans serpiginosa (EPS) is a rare reactive perforating dermatosis that is characterized by the transepidermal elimination of abnormal elastic fibers. Penicillamine, which is one of the clear triggers for EPS, is a heavy metal chelator that is primarily used for disorders such as cystinuria and Wilson's disease. It may cause alterations in the dermal elastic tissue such as pseudo-pseudoxanthoma elasticum, acquired cutis laxa, EPS and anetoderma. Herein we present a case of cutis laxa and EPS in a 34-year-old man who was previously on a long-term, high-dose of penicillamine for Wilson's disease. The combination of EPS and cutis laxa induced by penicillamine has rarely been reported and we report the first such case in Korea.