Mutations in the NPHS1 gene cause congenital nephrotic syndrome of the Finnish type presenting before the first 3 months of life. Recently, NPHS1 mutations have also been identified in ...childhood-onset steroid-resistant nephrotic syndrome and milder courses of disease, but their role in adults with focal segmental glomerulosclerosis remains unknown. Here we developed an in silico scoring matrix to evaluate the pathogenicity of amino-acid substitutions using the biophysical and biochemical difference between wild-type and mutant amino acid, the evolutionary conservation of the amino-acid residue in orthologs, and defined domains, with the addition of contextual information. Mutation analysis was performed in 97 patients from 89 unrelated families, of which 52 presented with steroid-resistant nephrotic syndrome after 18 years of age. Compound heterozygous or homozygous NPHS1 mutations were identified in five familial and seven sporadic cases, including one patient 27 years old at onset of the disease. Substitutions were classified as ‘severe’ or ‘mild’ using this in silico approach. Our results suggest an earlier onset of the disease in patients with two ‘severe’ mutations compared to patients with at least one ‘mild’ mutation. The finding of mutations in a patient with adult-onset focal segmental glomerulosclerosis indicates that NPHS1 analysis could be considered in patients with later onset of the disease.
To date, very few cases with adult-onset focal segmental glomerulosclerosis (FSGS) carrying NPHS2 variants have been described, all of them being compound heterozygous for the p.R229Q variant and one ...pathogenic mutation.
Mutation analysis was performed in 148 unrelated Spanish patients, of whom 50 presented with FSGS after 18 years of age. Pathogenicity of amino acid substitutions was evaluated through an in silico scoring system. Haplotype analysis was carried out using NPHS2 single nucleotide polymorphism and microsatellite markers.
Compound heterozygous or homozygous NPHS2 pathogenic mutations were identified in seven childhood-onset steroid-resistant nephrotic syndrome (SRNS) cases. Six additional cases with late childhood- and adult-onset SRNS were compound heterozygotes for p.R229Q and one pathogenic mutation, mostly p.A284V. p.R229Q was more frequent among SRNS cases relative to controls (odds ratio=2.65; P=0.02). Significantly higher age at onset of the disease and slower progression to ESRD were found in patients with one pathogenic mutation plus the p.R229Q variant in respect to patients with two NPHS2 pathogenic mutations.
NPHS2 analysis has a clinical value in both childhood- and adult-onset SRNS patients. For adult-onset patients, the first step should be screening for p.R229Q and, if positive, for p.A284V. These alleles are present in conserved haplotypes, suggesting a common origin for these substitutions. Patients carrying this specific NPHS2 allele combination did not respond to corticoids or immunosuppressors and showed FSGS, average 8-year progression to ESRD, and low risk for recurrence of FSGS after kidney transplant.
La poliquistosis renal autosómica dominante (PQRAD) es la causa más frecuente de nefropatía genética y representa entre el 6 y el 10% de los pacientes en terapia de reemplazo renal (TRR).
Muy pocos ...ensayos prospectivos, aleatorizados o estudios clínicos abordan el diagnóstico y el tratamiento de este trastorno relativamente frecuente. No hay guías clínicas disponibles hasta la fecha. Este es un documento de consenso revisada de la versión anterior del 2014, que presenta las recomendaciones del Grupo de Trabajo Español de Enfermedades Renales Hereditarias, acordadas tras la búsqueda bibliográfica y discusiones. Los niveles de evidencia en su mayoría son C y D según el Centro de Medicina Basada en Evidencia (Universidad de Oxford). Las recomendaciones se relacionan, entre otros temas, con el uso de diagnóstico por imágenes y genético, el manejo de la hipertensión, el dolor, las infecciones y el sangrado quístico, la afectación extrarrenal, incluida la enfermedad poliquística hepática y los aneurismas craneales, el manejo de la enfermedad renal crónica y el TRR, así como el seguimiento de niños con PQRAD. Se proporcionan recomendaciones sobre terapias específicas para la PQRAD, así como la recomendación para evaluar la rápida progresión.
Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent cause of genetic renal disease and accounts for 6–10% of patients on kidney replacement therapy (KRT).
Very few prospective, randomized trials or clinical studies address the diagnosis and management of this relatively frequent disorder. No clinical guidelines are available to date. This is a revised consensus statement from the previous 2014 version, presenting the recommendations of the Spanish Working Group on Inherited Kidney Diseases, which were agreed to following a literature search and discussions. Levels of evidence mostly are C and D according to the Centre for Evidence-Based Medicine (University of Oxford). The recommendations relate to, among other topics, the use of imaging and genetic diagnosis, management of hypertension, pain, cyst infections and bleeding, extra-renal involvement including polycystic liver disease and cranial aneurysms, management of chronic kidney disease and KRT and management of children with ADPKD. Recommendations on specific ADPKD therapies are provided as well as the recommendation to assess rapid progression.
Galloway-Mowat syndrome (GAMOS) is a rare autosomal recessive disorder characterized by early-onset nephrotic syndrome and microcephaly with brain anomalies. WDR73 pathogenic variants were described ...as the first genetic cause of GAMOS and, very recently, four novel causative genes, OSGEP, LAGE3, TP53RK, and TPRKB, have been identified.
We present the clinical and genetic characteristics of two unrelated infants with clinical suspicion of GAMOS who were born from consanguineous parents. Both patients showed a similar clinical presentation, with early-onset nephrotic syndrome, microcephaly, brain atrophy, developmental delay, axial hypotonia, and early fatality. We identified two novel likely disease-causing variants in the OSGEP gene. These two cases, in conjunction with the findings of a literature review, indicate that OSGEP pathogenic variants are associated with an earlier onset of nephrotic syndrome and shorter life expectancy than WDR73 pathogenic variants.
Our findings expand the spectrum of pathogenic variants in the OSGEP gene and, taken in conjunction with the results of the literature review, suggest that the OSGEP gene should be considered the main known monogenic cause of GAMOS. Early genetic diagnosis of GAMOS is of paramount importance for genetic counseling and family planning.
Tuberous sclerosis (TS) is a rare autosomal dominant systemic disease with an estimated prevalence of 1/6000. Renal angiomyolipoma (AML) is a benign tumour with high morbidity frequently present in ...TS. The aim of the study was to test the effect of rapamycin in reducing the volume of AML in TS.
Twenty four-month prospective open-label, single arm, unicentre Phases II andIII study. The primary endpoint was to evaluate the effect of treatment on the reduction of at least 50% AML volume from baseline at 24 months. The secondary endpoints were: average tumour reduction, surgical complications, skin lesions and drug safety.The study population comprised 17 patients, aged >10 years who were diagnosed with TS and had ≥1 renal AML >2 cm of diameter and had a serum creatinine < 2mg/dl and urine protein/creatinine ratio < 22.6 mg/mmol. The trial was conducted at Fundació Puigvert. Rapamycin was given to achieve stable plasma levels between 4 and 8 ng/ml. AML volume was estimated using orthogonal measurements by MRI at baseline, 6, 12 and 24 months.
Ten out of 17 patients were success responders for the main outcome -58.8%, 95%CI: 32.9% to 81.6%-. After 6 months of therapy, the mean volume decrease was 55.18% (5.01 standard error (SE); p<0.001) and 66.38% (4.41 SE; p<0.001) at year 1. There was no significant decrease between year 1 and 2. According to RECIST criteria, all patients achieved a partial response at year 1 and all but two had already achieved this partial response after 6 months.The main analysis was performed according to the intention-to-treat principle analysis. Tumour volume was analyzed over time by means of mixed models for repeated measurement analysis. We used the baseline tumour volume as a covariate for the absolute change and percentage change from baseline data. The analysis was performed using SAS version 9.2 software, and the level of significance was established at 0.05 (two-sided).
This study show that mTOR inhibitors are a relatively safe, efficacious and less aggressive alternative than currently available options in the management of AML in TS.
EudraCT number: 2007-005978-30, ClinicalTrials.gov number: NCT0121712.
Height-adjusted total kidney volume (htTKV) is the best marker of disease progression in early autosomal dominant polycystic kidney disease (ADPKD) when renal function still remains normal. The ...usefulness of cystatin-C as a biomarker to assess renal function according to renal volume has not been studied in ADPKD patients.
Observational and cross-sectional study of 62 ADPKD patients. htTKV, creatinine and cystatin-C estimated glomerular filtration rate (eGFR) were determined. Correlations between htTKV and eGFR were studied. A control group was used to determine the association between renal function differences and htTKV.
htTKV significantly correlated with cystatin-C-eGFR (r = -0.384, p = 0.002) but not with creatinine-eGFR (r = -0.225, p = 0.078). With htTKV stratified into tertiles, a significant difference of cystatin-C-eGFR but not in creatinine-eGFR was detected in the third tertile when compared with the first tertile group (110.0±22.2 vs 121.3±7.2; p = 0.023 and 101.8±17.2 vs 106.9±15.1; p = 0.327 respectively). When cystatin-C-eGFR of the controls was used as the reference, htTKV above 605 ml/m identified with a 75% sensitivity and 84.9% specificity those patients with a significant worse kidney function. However, this cut-off value could not be identified using creatinine-eGFR.
Cystatin-C-eGFR but not creatinine-eGFR correlated with htTKV in ADPKD patients in early stages of the disease. Differences in cystatin-C-eGFR but not in creatinine-eGFR have been identified through htTKV tertiles. A htTKV above 605 ml/m is associated with a worse renal function only if cystatin-C-eGFR is used. Cystatin-C-eGFR should be studied in prospective studies of early stages of ADPKD to determine its usefulness as an early marker of disease progression.
Fabry disease (FD) is a rare, X-linked disorder caused by mutations in the GLA gene encoding the enzyme α-galactosidase A. Complete or partial deficiency in this enzyme leads to intracellular ...accumulation of globotriaosylceramide (Gb3) and other glycosphingolipids in many cell types throughout the body, including the kidney. Progressive accumulation of Gb3 in podocytes, endothelial cells, epithelial cells, and tubular cells contribute to the renal symptoms of FD, which manifest as proteinuria and reduced glomerular filtration rate leading to renal insufficiency. A correct diagnosis of FD, although challenging, has considerable implications regarding treatment, management, and counseling. The diagnosis may be confirmed by demonstrating the enzyme deficiency in males and by identifying the specific GLA gene mutation in male and female patients. Treatment with enzyme replacement therapy, as part of the therapeutic strategy to prevent complications of the disease, may be beneficial in stabilizing renal function or slowing its decline, particularly in the early stages of the disease. Emergent treatments for FD include the recently approved chaperone molecule migalastat for patients with amenable mutations. The objective of this report is to provide an updated overview on Fabry nephropathy, with a focus on the most relevant aspects of its epidemiology, diagnosis, pathophysiology, and treatment options.
Fabry disease or also called Anderson-Fabry disease (FD) is a rare disease caused by pathogenic variants in the GLA gene, located on the X chromosome. This gene is involved in the metabolism of ...glycosphingolipids and its pathogenic variants cause a deficit or absence of α-galactosidase A causing the deposition of globotriaosylceramide throughout the body. Females have a variable phenotypic expression and a better prognosis than males. This is due to the X chromosome inactivation phenomenon. We present a clinical case of Fabry disease in a female with predominantly renal involvement and demonstrate how the X chromosome inactivation phenomenon is tissue dependent, showing preferential inactivation of the mutated allele at the renal level.
La enfermedad de Fabry o también llamada de Anderson-Fabry (EF) es una enfermedad rara, causada por variantes patogénicas en el gen GLA, localizado en el cromosoma X. Este gen interviene en el metabolismo de los glucoesfingolípidos y variantes patogénicas en el mismo causan déficit o ausencia de la α-galactosidasa A ocasionando el depósito de globotriaosilceramida en todo el organismo. Las mujeres presentan una expresión fenotípica variable y de mejor pronóstico que los varones. Esto es debido al fenómeno de inactivación del cromosoma X. Presentamos un caso clínico de enfermedad de Fabry en una mujer con afectación predominantemente renal y demostramos cómo el fenómeno de la inactivación del cromosoma X es tejido dependiente, mostrando una inactivación preferencial del alelo mutado a nivel renal.
Objective
Fabry disease is a progressive disorder caused by deficiency of the α-galactosidase A enzyme (α-Gal A), leading to multisystemic organ damage with heterogenous clinical presentation. The ...addition of the oral chaperone therapy migalastat to the available treatment options for Fabry disease is not yet universally reflected in all treatment guidelines. These consensus recommendations are intended to provide guidance for the treatment and monitoring of patients with Fabry disease receiving migalastat.
Methods
A modified Delphi process was conducted to determine consensus on treatment decisions and monitoring of patients with Fabry disease receiving migalastat. The multidisciplinary panel comprised 14 expert physicians across nine specialties and two patients with Fabry disease. Two rounds of Delphi surveys were completed and recommendations on the use of biomarkers, multidisciplinary monitoring, and treatment decisions were generated based on statements that reached consensus.
Results
The expert panel reached consensus agreement on 49 of 54 statements, including 16 that reached consensus in round 1. Statements that reached consensus agreement are summarized in recommendations for migalastat treatment and monitoring, including baseline and follow-up assessments and frequency. All patients with Fabry disease and an amenable mutation may initiate migalastat treatment if they have evidence of Fabry-related symptoms and/or organ involvement. Treatment decisions should include holistic assessment of the patient, considering clinical symptoms and organ involvement as well as patient-reported outcomes and patient preference. The reliability of α-Gal A and globotriaosylsphingosine as pharmacodynamic response biomarkers remains unclear.
Conclusion
These recommendations build on previously published guidelines to highlight the importance of holistic, multidisciplinary monitoring for patients with Fabry disease receiving migalastat, in addition to shared decision-making regarding treatments and monitoring throughout the patient journey.
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