Identificación de variantes del gen NPHS2 en niños con síndrome nefrótico corticorresistente / NPHS2 Mutation analysis study in children with steroid-resistant nephrotic syndrome

Resumen: La podocina es una proteína localizada en el diafragma de filtración glomerular donde participa en la regulación de la filtración glomerular. Las mutaciones del gen NPHS2, que codifica a la podocina, son la principal causa de síndrome nefrótico corticorresistente (SNCR) autosómico recesivo en niños. Objetivos: Identificar mutaciones de NPHS2 en niños chilenos con SNCR, y establecer la prevalencia de las variantes más frecuentes en un grupo de adultos sanos. Pacientes y método: Análisis mutacional de NPHS2 en 34 niños chilenos con SNCR. Una vez identificadas las dos variantes de NPHS2 de mayor frecuencia, se realizó un screening de estas mutaciones en 223 adultos sanos. El análisis mutacional se realizó por secuenciación directa de los ocho exones codificantes amplificados por reacción de polimerasa en cadena. La secuenciación del DNA se realizó mediante método fluorométrico y las secuencias fueron evaluadas con el software SeqPilot. La asociación entre la presencia de variantes de NPHS2 y SNCR se calculó comparando las frecuencias alélicas entre los pacientes con SNCR y los voluntarios sanos utilizando prueba exacta de Fisher. Se consideró significativo p < 0,05. Resultados: Se detectaron mutaciones patogénicas de NPHS2 en siete de los 34 pacientes (21%) estudiados, de los cuales seis resultaron heterocigotos para p.R229Q y p.A284 V. En voluntarios sanos la prevalencia de p.R229Q fue de 2,46%. Conclusiones: Este estudio muestra que p.R229Q y p.A284 V son las variantes de NPHS2 más frecuentes en niños chilenos con SNCR. Por primera vez se describe esta asociación en niños chilenos, en base a la cual es posible proponer una estrategia de screening para estudio genético en pacientes con SNCR y sus familias. Se propone una estrategia de búsqueda de p.R229Q y p.A284 V en forma paralela o secuencial en estos pacientes.

Abstract: Podocin is a protein located in the glomerular slit diaphragm where it takes part in the regulation of glomerular filtration. Mutations of the NPHS2 gene that codes podocin are the main cause of autosomal recessive steroid resistant nephrotic syndrome (SRNS). Objectives: To identify the NPHS2 mutations in Chilean children with SRNS, and to determine the prevalence of the most common variants in a group of healthy adults. Patients and methods: Mutation analysis of NPHS2 in 34 Chilean children with SRNS. Once the two most common variants of NPHS2 were identified, screening for these mutations was performed on 233 healthy adults. The mutation analysis was performed by the direct sequencing of the eight coding exons by polymerase chain reaction amplification. The DNA sequencing was performed using a fluorometric method, and then evaluated with SeqPilot™ software. The relationship between the presence of NPHS2 variants and SRNS was calculated by comparing the allele frequency between patients with SRNS and those of the healthy volunteers using the exact Fisher test. A P < .05 was considered significant. Results: Pathogenic NPHS2 mutations were detected in 7 (21%) of the 34 patients studied, of which 6 were heterozygotes for p.R229Q and p.A284 V. The presence of p.R229Q was 2.46% in the healthy volunteers. Conclusions: This study shows that p.R229Q and p.A284 V are the most frequent variants in Chilean children with SRNS. It is the first time that this relationship has been reported in Chilean children. Based on this, a screening strategy is proposed for the genetic study in patients with SRNS and their families. A parallel or sequential search strategy for p.R229Q and p.A284 V in these patients is proposed.

Steroid-resistant idiopathic nephrotic syndrome in children: long-term follow-up and risk factors for end-stage renal disease / Síndrome nefrótica idiopática córtico-resistente na criança: evolução e fatores de risco para falência renal crônica

INTRODUTION: Steroid resistant idiopathic nephrotic syndrome (SRINS) in children is one of the leading causes of progression to chronic kidney disease stage V (CKD V)/end stage renal disease (ESRD). OBJECTIVE: The aim of this retrospective study is to evaluate the efficacy of immunosuppressive drugs (IS) and to identify risk factors for progression to ESRD in this population. METHODS: Clinical and biochemical variables at presentation, early or late steroid resistance, histological pattern and response to cyclosporine A (CsA) and cyclophosfamide (CP) were reviewed in 136 children with SRINS. The analyzed outcome was the progression to ESRD. Univariate as well as multivariate Cox-regression analysis were performed. RESULTS: Median age at onset was 5.54 years (0.67-17.22) and median follow up time was 6.1 years (0.25-30.83). Early steroid-resistance was observed in 114 patients and late resistance in 22. Resistance to CP and CsA was 62.9% and 35% respectively. At last follow-up 57 patients reached ESRD. The renal survival rate was 71.5%, 58.4%, 55.3%, 35.6% and 28.5% at 5, 10, 15, 20 and 25 years respectively. Univariate analysis demonstrated that older age at onset, early steroid-resistance, hematuria, hypertension, focal segmental glomerulosclerosis (FSGS), and resistance to IS were risk factors for ESRD. The Cox proportional-hazards regression identified CsAresistance and FSGS as the only predictors for ESRD. CONCLUSION: Our findings showed that CsA-resistance and FSGS were risk factors for ESRD.

INTRODUÇÃO: A síndrome nefrótica idiopática córtico-resistente (SNICR) é uma das principais causas de falência renal crônica (FRC)/doença renal crônica estadio V (DRC V) em crianças. Objetivo: Avaliar a resposta aos imunossupressores e identificar fatores de risco para a FRC. MÉTODOS: Variáveis clínicas e bioquímicas na apresentação, resistência inicial ou tardia aos esteroides, lesão histológica e resposta à ciclosporina A (CsA) e à ciclofosfamida (CF) foram analisados retrospectivamente em 136 crianças com SNICR. O desfecho analisado foi a progressão para FRC e os métodos utilizados foram a análise univariada e a regressão multivariada de Cox. RESULTADOS: A idade mediana do início da doença foi de 5,54 anos (0,67-17,22) e o tempo mediano de seguimento foi de 6,1 anos (0,25-30,83). Resistência inicial aos esteroides ocorreu em 114 pacientes e tardia em 22. Resistência à CF e à CsA ocorreu em 62,9% e 35% dos pacientes, respectivamente. FRC ocorreu em 57 pacientes. A sobrevida renal foi de 71,5%, 58,4%, 55,3%, 35,6% e 28,5% aos 5, 10, 15, 20 e 25 anos, respectivamente. A análise univariada demonstrou que a idade maior ao início da doença, resistência inicial aos esteroides, hematúria, hipertensão, glomeruloesclerose segmentar e focal (GESF) e resistência aos imunossupressores foram fatores de risco para FRC. A regressão de Cox identificou a resistência à CsA e a GESF como os únicos fatores preditores para FRC. CONCLUSÃO: Nossos achados mostraram que a resistência à ciclosporina e a presença de GESF foram fatores de risco para a progressão para DRCV.

Immunosupressive therapy in children with steroid-resistant nephrotic syndrome: single center experience / Tratamento com imunossupressores em crianças com síndrome nefrótica resistente a corticosteróide: experiência de um único centro

INTODUCTION: Nephrotic syndrome is one of the most frequent glomerular diseases among children, and steroid therapy remains as the treatment choice. In spite of this, 10 to 15% of the patients are steroidresistant, and the best therapy for such cases has never been defined. Mycophenolate acid (MA) is one of the treatments used in such situations. OBJECTIVE: To describe the clinical behavior of children diagnosed with steroid-resistant nephrotic syndrome (SRNS) and to assess the therapeutic response to MA. METHODS: This was a retrospective and descriptive study. RESULTS: 26 clinical records of patients with SRNS; 70% male and 30% female. All patients underwent kidney biopsies, which showed a predominance of focal segmental glomerulosclerosis (FSGS). The immunosuppresive drugs used were: Mycophenolate mofetil (MMF) 100%, Cyclosporine 69.2%, Cyclophosphamide 23.1%, and Rituximab 23%. One month after treatment initiation with MMF 61.5% achieved remission. The median of relapses per year for the patients was 3 (p25: 2.75 - p75: 4). This median became 1 (p25: 1 - p75: 3.25) after using this medication (p = 0.08). Furthermore, prior to the start of the MMF treatment, the median of the steroid dose was 1 (p25: 0.5- p75: 1.62) mg/k/day. After using MMF, this median became 0.07 (p25: 0 - p75: 0.55) mg/k/day (p < 0.001), in 8 patients prednisolone was stopped. CONCLUSION: In our experience, treatment with MMF showed positive results such as decrease in the frequency of relapses, less proteinuria, and reduction in the dose of steroids administered without deterioration of glomerular filtration rates. However, more studies are needed to assess efficacy, safety, and optimal dosage.

INTRODUÇÃO: A síndrome nefrótica é uma das mais frequentes doenças glomerulares em crianças e o tratamento com corticosteróides ainda é o tratamento de escolha. Apesar disso, 10 a 15% dos pacientes são resistentes a corticosteróides, e o melhor tratamento para tais casos ainda não foi definido. O ácido micofenólico (AM) é um dos tratamentos usados em tais situações. OBJETIVO: Descrever o comportamento clínico de crianças diagnosticadas com síndrome nefrótica resistente a corticosteróide (SNRC) e avaliar a resposta terapêutica ao AM. MÉTODOS: Esse foi um estudo retrospectivo e descritivo. RESULTADOS: 26 registros de pacientes com SNRC; 70% homens e 30% mulheres. Todos os pacientes foram submetidos a biópsias renais, o que mostrou predominância de glomeruloesclerose segmentar focal (GESF). Os medicamentos imunossupressores utilizados foram: Mofetil Micofenolato (MMF) 100%; Ciclosporina 69,2%; Ciclosfosfamida 23,1%; e Rituximabe 23%. Um mês após início do tratamento com MMF, 61,5% tiveram remissão. A mediana das recidivas por ano para os pacientes foi de 3 (p25: 2,75 - p75: 4). Essa mediana se tornou 1 (p25: 1 - p75: 3,25) após o uso da medicação (p = 0,08). Além disso, antes do início do tratamento com MMF, a mediana da dose de corticosteróide foi de 1 (p25: 0.5 - p75: 1.62) mg/k/ dia. Após a utilização do MMF, essa mediana se tornou 0,07 (p25: 0 - p75: 0,55) mg/k/dia (p < 0,001), em 8 pacientes a prednisolona foi interrompida. CONCLUSÃO: em nossa casuística, o tratamento com MMF mostrou resultados positivos, tais como a redução na frequência de recidivas, menos proteinúria, e redução da dose de corticosteróide administrada sem deterioração nas taxas de filtração glomerular. Entretanto, mais estudos são necessários para se avaliar a eficácia, segurança e otimização da dosagem.

Ankle brachial index in children with steroid-resistant nephrotic syndrome

This study aimed to assess the ankle brachial index [ABI] as a predictor of peripheral arterial diseases [PAD] in children with steroid-resistant nephrotic syndrome [NS]. Twenty children [11 males and 9 females] attending the Pediatric Nephrology Outpatient Clinic of El-Minia University Hospital, Egypt, were enrolled in this study. Their age ranged between 5 and 15 years with a mean of 10.75 +/- 3.31 years. They had proteinuria and were dependent on steroid therapy. Twenty healthy age- and sex-matched children served as a control group. All patients and controls underwent a thorough history-taking and clinical examination. All subjects in the study underwent laboratory investigations, including a urine analysis [24-hour test for protein in urine, and levels of serum urea and creatinine, triglycerides, and cholesterol]. A renal biopsy was done to diagnose the children's histopathological type of NS. A Doppler study was done to determine patients' ABI. ABI was significantly higher in the patient group than in the control group [P <0.0001]. There was a negative correlation between ABI and duration of treatment [r value = 0.77 and P <0.001]. ABI is simple non-invasive manoeuvre that can reliably assess arterial stiffness as an early predictor of atherosclerosis in nephrotic patients with long duration of both illness and steroid therapy

Anesthetic management of a child with nephrotic syndrome undergoing open heart surgery: Report of a rare case.

The congenital nephrotic syndrome (NS) in infancy and childhood is an important entity but combination with acyanotic congenital heart disease is uncommon. Anesthesia in such cases is challenging because of associated problems like hypo-protienemia, anti-thrombin III deficiency, edema, hyperlipidemia, coagulopathy, cardiomyopathy, immunodeficiency, increased lung water etc. We describe anesthetic management of a patient with childhood NS and sinus venosus atrial septal defect (ASD) undergoing open heart surgery. We also suggest guidelines for safe conduct of anesthesia and CPB in such patients.

Tacrolimo para o tratamento da síndrome nefrótica primária em crianças e adolescentes / Tacrolimus for the treatment of primary nephrotic syndrome in children and adolescents

A síndrome nefrótica (SN) é caracterizada por proteinúria maciça, hipoalbuminemia, edema e hiperlipidemia e ocorre pelo aumento da permeabilidade da membrana basal glomerular. Pode ser dividida em secundária, quando causada por alguma outra doença, ou idiopática. Em crianças, a síndrome nefrótica idiopática (SNI) representa 90% dos casos diagnosticados antes dos 10 anos de idade e 50% dos que se apresentam após essa idade. Apesar de menos frequente, a avaliação inicial deve afastar a presença de causas secundárias, como doenças sistêmicas, infecções, neoplasias e uso de medicamentos. O diagnóstico de SNI em crianças e adolescentes é baseado nos seguintes critérios clínicos e laboratoriais. O paciente deverá apresentar todos os critérios abaixo: -edema; e -proteinúria nefrótica ­ proteinúria acima de 50 mg/kg/dia ou acima de 40 mg/m2/h ou acima de 3,5 g/24 h/1,73 m2 ou índice proteinúria/creatininúria (IPC) acima de 2,0; e -hipoalbuminemia ­ albumina sérica abaixo de 2,5 g/dl; e -hiperlipidemia (colesterol total igual ou acima de 240 mg/dl ou triglicerídios igual ou acima 200 mg/dl. Os pacientes são classificados de acordo com a resposta ao tratamento nas seguintes categorias: -em remissão completa; -em remissão parcial; -com resistência ao glicocorticoide; -com recidiva; -com recidivas frequentes; -com dependência ao corticosteroide; -com resistência ao corticosteroide; com resistência ao corticosteroide. Esquematicamente, o tratamento pode ser dividido em: -tratamento inicial (primeiro episódio); -síndrome nefrótica sensível ao corticosteroide; -síndrome nefrótica resistente ao corticosteroide. O tacrolimo (TAC) é um inibidor da calcineurina largamente utilizado na prevenção da rejeição aguda no transplante de órgãos. Trata-se de um antibiótico macrolídeo, que inibe a ativação de um fator de transcrição essencial para a produção de citocinas pelo linfócito CD4, resultando em diminuição de produção de interleucina-2 (IL-2) e interferon-gama. A CONITEC, na 4ª reunião ordinária realizada no dia 10/05/2012, decidiu recomendar a ampliação de uso no SUS do medicamento tacrolimo para tratamento da síndrome nefrótica primária em crianças e adolescentes. O medicamento será utilizado como alternativa terapêutica à ciclosporina quando ocorrerem efeitos adversos associados ao seu uso­hiperplasia gengival e hipertricose­, e conforme PCDT a ser elaborado pelo Ministério da Saúde. A Portaria SCTIE/MS Nº 35, de 27 de setembro de 2012 - Torna pública a decisão de incorporar o medicamento tacrolimo para o tratamento da Síndrome Nefrótica Primária no Sistema Único de Saúde (SUS).

Síndrome nefrótico congénito por mutación del gen de la nefrina: caso clínico / Congenital nephrotic syndrome due to mutation of nephrine gene: clinical case

Congenital Nephrotic Syndrome (CNS) is defined as a corticoresistant nephrotic syndrome which appears in the first 90 days of life. NPHS1 gene mutations, codifying nephrine cause nearly 40 percent of the cases. Such a clinical case has not yet been described in Chile. Objective: Describe a patient with CNS and his genetic study. Clinical case: Full-term 38 week male newborn, birth weight 2620 gr, height 48,5 cm, ALPGAR 9/10. Head circumf: 33 cm. First child, well controlled pregnancy. 16 days after birth, he develops edema, massive proteinuria (3,2 gr/ dl), hypoalbuminemia (0,79 mg/dl) and hypercholesterolemia ( total cholesterol: 318 mg/dl). Renal sonogram showed increase in size and echogenicity in both kidneys, and loss of corticomedullar differentiation. Renal biopsy showed diffuse mesangial glomeruloesclerosis. Genetic study for NPHS1 was performed through direct sequencing of 29 exons and adjacent regions of introns chromosome 19q13.1. Analysis disclosed C567X, ho-mozygote mutation. Conclusions: The first case of Nephrine mutation causing CNSis described in Chile. The importance of genetic studies in these patients is highlighted for clinical decision making.

El síndrome nefrótico congénito (SNC) se define como un síndrome nefrótico córticoresistente que aparece en los primeros 90 días de vida. Mutaciones en el gen NPHS1 que codifica a la nefrina son causantes de aproximadamente del 40 por ciento de los niños con SNC. En Chile no se ha descrito hasta ahora esta mutación asociada al cuadro clínico. Objetivo: Describir el caso de un paciente con SNC y su estudio genético. Caso clínico: Paciente de sexo masculino, RNT 38 semanas, PRN 2620 gr, TN 48,5 cm APGAR 9/10. CC: 33 cm. Embarazo controlado primer hijo. A los 16 días comienza con edema, proteinuria masiva (3,2 gr/dl), hipoalbuminemia (0,79 mg/dl) e hipercolesterolemia (colesterol total: 318 mg/dl). Se descarta TORCH (-). La ecografía renal mostró un aumento de tamaño y de ecogenicidad de ambos riñones, pérdida de diferenciación corticomedular. La biopsia renal se informó como glomeruloesclerosis mesangial difusa. El estudio genético para NPHS1 se realizó por secuenciación directa de los 29 exones y las regiones adyacentes de los intrones en el cromosoma 19q13.1 El análisis demostró una mutación C567X, homocigoto. Conclusiones: Se describe el primer caso de mutación para Nefrina en un SNC chileno. Se destaca la importancia del estudio genético en estos pacientes debido a las implicancias en las decisiones clínicas y terapéuticas.

Options of the treatment in steroid resistant nephrotic syndrome in children in central child teaching hospital-Baghdad

The therapy of steroid resistant nephritic syndrome [SRNS] is still a matter of controversy. To assess the options of treatment in SRNS. A retrospective study to 50 patient randomly selected in the Central Child Teaching Hospital during study period from Jan. 2006 till July 2008. The patient age was between 6 months - 18 years. All patients who had failed to achieve an improvement in proteinuria after minimum of 4 weeks [up to 8 weeks] of prednisolone [PDN] in a dosage 2 mg/kg/day were taken. Only the patients with idiopathic nephritic syndrome [45 patients] were involved in the study but the patients with secondary nephritic syndrome and congenital neprosis were excluded from the study. Each patient were individualized to the type of pathology and to the type of medication used. Forty five patients were included in the study, the age range between 6 months -18 years. Twenty eight patients were male and 17 were female, M: F ration 1.64: 1 regarding the type of pathology, 20 patients with focal segmental glomerulosclerosis [FSGS], 11 patients with minimal change nephritic syndrome [MCNS], 8 patients with diffuse mesagnial proliferation [DMP] and 6 patients were unknown biopsy [not down biopsy]. The drugs that used were methyl prednisolone [MP] in 17 patients. Every other day steroid [EODS] in 10 patients, cyclosporine A [CsA] plus EODS in 16 patients [10 patients as first option and 6 patients as second option, cyclophosphamide [CYS] used in 8 patients [6 patients as first option and 2 patients as second option] and chlorambucil wee used in 2 patients only. The response was higher in patients who received EODS [50%], followed by the patients who received CsA plus EODS [25%] then the patients who received MP [23.5%] and the patients who received CYS [12.5%] and chlorambucil [zero%]. The response to treatment was higher in females than males, 11 out of 28 males [39.28%] responded to treatment while 7 of 17 female [41.17%] responded to treatment. The patients with early presentation responded to treatment higher than those with late presentation, so 12 of 19 patients [63.15%] presented early while 10 of 26 patients [38.46%] presented ate. According to histopathology, the patients with unknown etiology had higher rate of response, 3 out of 6 patients [50%] responded to treatment followed by 7 of 20 [35%] patients with FSGS, then 2 of 8 [25%] patients with DMP, then 2 of 11 [18.18%] patients with MCNS. The drugs used are the common drugs and EODS is preferable type of medication used in SRNS

[Treatmentofsteroid-esistantidiopathicnephrosiswithimmunosuppressivetherapy in 30 children]

The aim of this study is to evaluate the efficacity of immunosuppressive therapy in steroid - resistant idiopathic nephrotic syndrome. 30 children present to the renal biopsy a focal and segmental glomerulosclerosis [HSF 18 cases], minimal change disease [LGM: 9 cases] and diffuse mesangial proliferation [PMD: 3 cases]. 9 of 11 patients did not respond to cyclophosphamid. 28 patients received the cyclosporine - prednisone combinaison with a cyclosensibility in 23 patients [80 per cent]. The mycophenolate mofetil [MMF] was used in 7 patients, and 3 were in remission. In this study 7 patients [23 per cent] develop a chronic renal failure. the cyclophosphamid has not beneficial effects. The cyclosporine is an effective therapeutic agent. MMF has emerged as an important new therapeutic option for the treatment of SNCR and HSF

Congenital Nephrotic Syndrome with adrenal calcification and cardiac malformation.

Congenital Nephrotic Syndrome (CNS) with adrenal calcification and CNS with congenital heart disease (CHD) have rarely been reported. However, CNS with both these rare associations has never been previously reported. Here we report a case of CNS with both rare associations, perhaps the first report from India to the best of our knowledge.

Síndrome de Denys-Drash: presentación de un caso / Denys-Drash's syndrome: a case report

El síndrome de Denys-Drash se caracteriza por pseudohemafroditismo masculino, tumor de Wilms y glomerulopatía con rápida progresión a la insuficiencia renal terminal, es producido por una mutación en el gen supresor TW1 localizado en el cromosoma 11p 13. La lesión glomerular se caracteriza por una esclerosis mesangial difusa. Reportamos un caso con genitales ambiguos, cariotipo 46 XY, síndrome nefrótico congénito a los 7 días de nacido, con rápida progresión a la insuficiencia renal terminal. Se hizo necesaria la diálisis peritoneal, y murió al mes de edad por sepsis generalizada. En el análisis del tejido renal se demuestra la esclerosis mesangial difusa

Congenital nephrotic syndrome.

A six week old baby girl from a closed Malay community in Hambantota presented with gradually increasing oedema since two weeks of age. She was oedematous, with gross non selective proteinuria, hypoproteinaemia and hypercholesterolaemaia. Congenital nephrotic syndrome is extremely rare and has not been reported previously in Sri Lanka.

Síndrome nefrótica: relato de um caso de esclerose mesangial difusa / Nephrotic syndrome: report of a case of diffuse mesangial sclerosis

Habib & Bois descreveram seis casos de um tipo específico de síndrome nefrótica infantil e designaram a entidade esclerose mesangial difusa, baseados em lesöes características. Relatamos o curso clínico e achados histopatológicos de biópsia renal, com estudo a microscopia eletrônica, em paciente com síndrome nefrótica congênita