Cystinuria: A rare cause of bladder stone

VCystinuria is an inherited metabolic disorder progressing with recurrent kidney stones due to impaired reabsorption of dibasic amino acids and arises from mutations in the SLC3A1 and SLC7A9 on chromosome 2. Here, we present the case of a 1-year 10-month-old male child with recurrent episodes of urinary tract infections. On evaluation, duplex kidneys and a large bladder calculus were found which was surgically managed. Stone analysis and the genetic study were suggestive of cystinuria.

Enfermedad de orina con olor a jarabe de arce: reporte de dos casos / Maple urine disease: two case reports

Introducción: La enfermedad de orina con olor a jarabe de arce (EOJA) es un trastorno del metabolismo de los aminoácidos de cadena ramificada (ACR). Tiene una incidencia de 1 en 85.000­185.000 recién nacidos (RN) vivos, siendo mayor en poblaciones con alta tasa de consanguineidad. Se debe al déficit del complejo enzimático BCKDC (Branched-chain alpha-keto acid dehydrogenase complex). Objetivo: Sensibilizar respecto al diagnóstico precoz, describiendo la presentación y evolución clínica de 2 casos presentados en menos de un año. Presentación del caso: Caso 1: Recién nacido de término (RNT), sin antecedentes mórbidos personales ni familiares, consulta al 11er día de vida (DDV) por cuadro de irritabilidad, rechazo alimentario, mirada fija e hipertonía. Hospitalizado por 55 días con progresiva mejoría neurológica. Al alta solo leve retraso del desarrollo psicomotor (RDSM). Caso 2: RNT, sin antecedentes mórbidos personales ni familiares, consultó al 12° DDV por cuadro de hipoactividad y rechazo alimentario. Hospitalizado por 70 días con evolución clínica y neurológica dificultosa. Al alta con trastorno deglutorio que requirió gastrostomía. En ambos casos se planteó sospecha de EOJA por aminoacidemia y aminoaciduria característica, confirmándose por medición cuantitativa de aminoácidos. Discusión: Existen cinco fenotipos diferentes, clasificados principalmente por presentación clínica y edad de debut, siendo el más frecuente la forma clásica (ambos casos). Resulta muy importante el diagnóstico precoz y manejo por su relación con el pronóstico neurológico, sin embargo, en Chile no se cuenta actualmente con un screening neonatal universal. El tratamiento se basa en un manejo nutricional estricto y la corrección de desequilibrios metabólicos e hidroelectrolíticos, ambos frecuentes en esta condición.

Introduction: The maple syrup urine disease (MSUD) is a metabolic disorder of branchedchain amino acids. It has an incidence of 1/85000 ­ 185000 live newborns being higher in in populations with a high rate of consanguinity. It is due to deficit BKDC enzyme complex (Branched-chain alpha-keto acid dehydrogenase complex). Objective: To raise awareness to early diagnosis, describing the presentation and clinical course of 2 cases presented in less than one year. Case report: Case 1: Full-term newborn with no personal or family history of morbidity presented the 11th day of life with irritability, food rejection, fixed stare and hypertonia. He was hospitalized for 55 days with progressive neurological improvement. At discharge only slightly delayed psychomotor development. Case 2: Full-term newborn with no personal or family history of morbidity presented the 12th day of life with hipoactivity and food rejection. He was hospitalized for 70 days with difficult clinical and neurological outcome. The patient was discharged with swallowing disorder that required gastrostomy. In both cases MSUP suspicion arises by aminoacidemia and aminoaciduria and confirmed by quantitative measurement of amino acids. Discussion: There are 5 different phenotypes classified chiefly by clinical presentation and age, being most frequent the classical form. It is very important to do an early diagnosis and management for its impact on neurological outcome; however, Chile does not currently has an universal neonatal screening. The treatment is based on a strict nutritional management and correction of metabolic and electrolyte imbalances, both common in this condition.

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.

A peculiar type of familial mental deficiency, probably due to metabolic disturbance

A Filipino family with seven children - five mentally retarded with two dead and three alive - is presented. The mental deficiency is accompanied by dwarfism, muscular dystrophy, osteoporosis, acidosis and aminoaciduria. The marked excretion of amino acid in the mentally retarded children is obvious. However, even in the mother and two other children who looked mentally normal, there is likewise a slight aminoaciduria. We are aware that due to lack of facilities, we could not do all the necessary examinations. We believe, however, that the examinations done so far are sufficient to furnish the evidence of a syndrome characterized by aminoaciduria, acidosis, dwarfism, mental deficiency and severe muscular dystrophy. Chromosome studies ought to be done as we are dealing with a familial disease, but so far we do not have the necessary material. (Summary and Conclusions)