Infection-related glomerulonephritis with IgA deposits (IRGN-IgA) is a rare disease but it is increasingly reported in the literature. Data regarding epidemiology and outcome are lacking, especially ...in Europe. We aimed to assess the clinical, pathologic and outcome data of IRGN-IgA.
Clinical and outcome data from patients from 11 French centers over the 2007-2017 period were collected retrospectively. We reviewed pathologic patterns and immunofluorescence of renal biopsies and evaluated C4d expression in IRGN-IgA. We analyzed the correlation between histological presentation and outcome.
Twenty-seven patients (23 men, mean age: 62 ± 15 years) were included. Twenty-one (78%) had Staphylococcus aureus infection and twelve (44%) were diabetic. At the time of biopsy, 95.2% had haematuria, 48.1% had a serum creatinine level of > 4 mg/dL, and 16% had hypocomplementemia. The most common pathologic presentation included mesangial (88.9%) and endocapillary proliferative glomerulonephritis (88.9%) with interstitial fibrosis and tubular atrophy (IF/TA) (85.1%). Diffuse and global glomerular C4d expression was found in 17.8%, mostly in biopsies with acute or subacute patterns, and was associated with a short delay between infection and renal biopsy compared to segmental and focal staining. After median follow-up of 13.2 months, 23.1% died, 46.2% had persistent renal dysfunction and 15.4% reached end-stage renal disease. Renal outcome was correlated to IF/TA severity.
Infection-related glomerulonephritis with IgA deposits is usually associated with Staphylococcus infections and mainly affects adult men. This entity has a poor prognosis which is correlated to interstitial fibrosis and tubular atrophy severity.
Numerous genes for monogenic kidney diseases with classical patterns of inheritance, as well as genes for complex kidney diseases that manifest in combination with environmental factors, have been ...discovered. Genetic findings are increasingly used to inform clinical management of nephropathies, and have led to improved diagnostics, disease surveillance, choice of therapy, and family counseling. All of these steps rely on accurate interpretation of genetic data, which can be outpaced by current rates of data collection. In March of 2021, Kidney Diseases: Improving Global Outcomes (KDIGO) held a Controversies Conference on “Genetics in Chronic Kidney Disease (CKD)” to review the current state of understanding of monogenic and complex (polygenic) kidney diseases, processes for applying genetic findings in clinical medicine, and use of genomics for defining and stratifying CKD. Given the important contribution of genetic variants to CKD, practitioners with CKD patients are advised to “think genetic,” which specifically involves obtaining a family history, collecting detailed information on age of CKD onset, performing clinical examination for extrarenal symptoms, and considering genetic testing. To improve the use of genetics in nephrology, meeting participants advised developing an advanced training or subspecialty track for nephrologists, crafting guidelines for testing and treatment, and educating patients, students, and practitioners. Key areas of future research, including clinical interpretation of genome variation, electronic phenotyping, global representation, kidney-specific molecular data, polygenic scores, translational epidemiology, and open data resources, were also identified.
Mutations in
and
cause autosomal dominant polycystic kidney disease (ADPKD). Experimental evidence suggests an important role of the polycystins in cardiac development and myocardial function. To ...determine whether ADPKD may predispose to the development of cardiomyopathy, we have evaluated the coexistence of diagnoses of ADPKD and primary cardiomyopathy in our patients.
Clinical data were retrieved from medical records for patients with a coexisting diagnosis of ADPKD and cardiomyopathies evaluated at the Mayo Clinic (1984-2015).
Among the 58 of 667 patients with available echocardiography data, 39 (5.8%) had idiopathic dilated cardiomyopathy (IDCM), 17 (2.5%) had hypertrophic obstructive cardiomyopathy, and 2 (0.3%) had left ventricular noncompaction. Genetic data were available for 19, 8, and 2 cases of IDCM, hypertrophic obstructive cardiomyopathy, and left ventricular noncompaction, respectively.
mutations were detected in 42.1%, 62.5%, and 100% of IDCM, hypertrophic obstructive cardiomyopathy, and left ventricular noncompaction cases, respectively.
mutations were detected only in IDCM cases and were overrepresented (36.8%) relative to the expected frequency in ADPKD (15%). In at least 1 patient from 3 IDMC families and 1 patient from a hypertrophic obstructive cardiomyopathy family, the cardiomyopathy did not segregate with ADPKD, suggesting that the
mutations may be predisposing factors rather than solely responsible for the development of cardiomyopathy.
Coexistence of ADPKD and cardiomyopathy in our tertiary referral center cohort appears to be higher than expected by chance. We suggest that
and
mutations may predispose to primary cardiomyopathies and that genetic interactions may account for the observed coexistence of ADPKD and cardiomyopathies.
Adenine phosphoribosyltransferase (APRT) deficiency is a rare autosomal recessive enzyme defect of purine metabolism that usually manifests as 2,8‐dihydroxyadenine (2,8‐DHA) nephrolithiasis and more ...rarely chronic kidney disease. The disease is most often misdiagnosed and can recur in the renal allograft. We analyzed nine patients with recurrent 2,8‐DHA crystalline nephropathy, in all of whom the diagnosis had been missed prior to renal transplantation. The diagnosis was established at a median of 5 (range 1.5–312) weeks following the transplant procedure. Patients had delayed graft function (n = 2), acute‐on‐chronic (n = 5) or acute (n = 1) allograft dysfunction, whereas one patient had normal graft function at the time of diagnosis. Analysis of allograft biopsies showed birefringent 2,8‐DHA crystals in renal tubular lumens, within tubular epithelial cells and interstitium. Fourier transformed infrared microscopy confirmed the diagnosis in all cases, which was further supported by 2,8‐DHA crystalluria, undetectable erythrocyte APRT enzyme activity, and genetic testing. With allopurinol therapy, the allograft function improved (n = 7), remained stable (n = 1) or worsened (n = 1). At last follow‐up, two patients had experienced allograft loss and five had persistent chronic allograft dysfunction. 2,8‐DHA nephropathy is a rare but underdiagnosed and preventable disorder that can recur in the renal allograft and may lead to allograft loss.
The authors report on nine patients with recurrent 2,8‐dihydroxyadenine nephropathy following renal transplantation, pointing to adenine phosphoribosyltransferase deficiency as a rare but significant cause of renal allograft dysfunction.
Autosomal dominant polycystic kidney disease (ADPKD), characterized by progressive cyst formation/expansion, results in enlarged kidneys and often end stage kidney disease. ADPKD is genetically ...heterogeneous; PKD1 and PKD2 are the common loci (∼78% and ∼15% of families) and GANAB, DNAJB11, and ALG9 are minor genes. PKD is a ciliary-associated disease, a ciliopathy, and many syndromic ciliopathies have a PKD phenotype. In a multi-cohort/-site collaboration, we screened ADPKD-diagnosed families that were naive to genetic testing (n = 834) or for whom no PKD1 and PKD2 pathogenic variants had been identified (n = 381) with a PKD targeted next-generation sequencing panel (tNGS; n = 1,186) or whole-exome sequencing (WES; n = 29). We identified monoallelic IFT140 loss-of-function (LoF) variants in 12 multiplex families and 26 singletons (1.9% of naive families). IFT140 is a core component of the intraflagellar transport-complex A, responsible for retrograde ciliary trafficking and ciliary entry of membrane proteins; bi-allelic IFT140 variants cause the syndromic ciliopathy, short-rib thoracic dysplasia (SRTD9). The distinctive monoallelic phenotype is mild PKD with large cysts, limited kidney insufficiency, and few liver cysts. Analyses of the cystic kidney disease probands of Genomics England 100K showed that 2.1% had IFT140 LoF variants. Analysis of the UK Biobank cystic kidney disease group showed probands with IFT140 LoF variants as the third most common group, after PKD1 and PKD2. The proximity of IFT140 to PKD1 (∼0.5 Mb) in 16p13.3 can cause diagnostic confusion, and PKD1 variants could modify the IFT140 phenotype. Importantly, our studies link a ciliary structural protein to the ADPKD spectrum.
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Abstract
Background and Aims
ADPKD is the most common inherited kidney disease in man, a major cause of end-stage renal disease and is a significant medical and economic burden worldwide. However, ...the impact of this major disease on the quality of life of patients with preserved kidney function has not been systematically explored.
Method
The CYSTic I study was an observational, prospective study designed to study the natural history of ADPKD in adult patients with preserved kidney function (eGFR ≥30 ml/min/1.73m2). 465 patients were recruited from six expert centres across Europe (Belgium, France, Italy, Netherlands, Spain and UK) with baseline data recorded including HR-QoL (Health-Related Quality of Life) incorporating a Kidney Disease QOL short form questionnaire (KDQoL-SF v1.3), MRI for Total Kidney Volume (TKV) and DNA for genotyping. The cohort was stratified by baseline eGFR, Ht-TKV or genotype and correlated with HR-QOL scores. Bivariate and multivariate analyses were applied to examine the relationship between HRQoL and variables of interest. KDQoL-SF scores were calculated using an online tool provided by the Rand organisation.
Results
Mean age of the participants was 44 years, 54.6% were female with a mean eGFR of 77ml/min/1.73m2 and Ht-TKV of 849ml/m. 72.3% had PKD1 mutations. 32.5% of participants reported flank pain that was not significantly correlated with eGFR, Ht-TKV or genotype. Of all the variables examined, flank pain showed significant negative associations with the highest number of KDQoL-SF subscale scores assessed (12/20).
Conclusion
Our results indicate that flank pain is common, likely to be under-reported in routine care but has a major negative impact on patient-reported quality of life.
Abstract Objectives The allopurinol dose is limited in chronic kidney disease, particularly stage 4/5 chronic kidney disease. Febuxostat has a hepatic metabolism and has been approved without dose ...adaptation in gouty patients with stage 1–3 chronic kidney disease. We aimed to study the safety and efficacy of febuxostat for stage 4/5 chronic kidney disease. Methods In this retrospective study, we included patients with (1) a diagnosis of gout, (2) febuxostat treatment, (3) estimated glomerular filtration rate ≤ 30 mL/min/1.73 m2 (Modification of Diet in Renal Disease formula) at febuxostat initiation and (4) follow-up for at least 3 months after febuxostat initiation. Efficacy, safety and variation in estimated glomerular filtration rate were analyzed. Results We included 73 patients (mean age 70.2 ± 11.8, 61 men, 31 with vascular chronic kidney disease and 18 renal transplantation) with gout (baseline serum uric acid level = 9.86 ± 2.85 mg/dL, mean gout duration 6.2 ± 7.0 years) from 10 academic centers. Comorbidities included cardiac failure (17.8%), hypertension (98.6%), diabetes mellitus (30.1%), dyslipidemia (64.8%) and history of cardiovascular events (38.4%). At the last visit (mean follow-up 68.5 ± 64.8 weeks), the daily dose of febuxostat was 40 mg for 7 patients (10.5%), 80 mg for 50 (74.6%) and 120 mg for 10 (14.9%). Serum uric acid level was < 6 mg/dL for 49 patients (67%). Renal function improved for 18 patients, was unchanged for 24 and worsened for 31; 19 patients experienced flares and 1 patient, limb edema. Conclusion Febuxostat seemed efficient in gouty patients with stage 4/5 chronic kidney disease. However, safety data were not clear regarding renal function. Larger studies are needed to assess safety.
Autosomal dominant polycystic kidney disease (ADPKD) is an inherited, progressive nephropathy accounting for 4-10% of end stage renal disease worldwide. PKD1 and PKD2 are the most common disease ...loci, but even accounting for other genetic causes, about 7% of families remain unresolved. Typically, these unsolved cases have relatively mild kidney disease and often have a negative family history. Mosaicism, due to de novo mutation in the early embryo, has rarely been identified by conventional genetic analysis of ADPKD families. Here we screened for mosaicism by employing two next generation sequencing screens, specific analysis of PKD1 and PKD2 employing long-range polymerase chain reaction, or targeted capture of cystogenes. We characterized mosaicism in 20 ADPKD families; the pathogenic variant was transmitted to the next generation in five families and sporadic in 15. The mosaic pathogenic variant was newly discovered by next generation sequencing in 13 families, and these methods precisely quantified the level of mosaicism in all. All of the mosaic cases had PKD1 mutations, 14 were deletions or insertions, and 16 occurred in females. Analysis of kidney size and function showed the mosaic cases had milder disease than a control PKD1 population, but only a few had clearly asymmetric disease. Thus, in a typical ADPKD population, readily detectable mosaicism by next generation sequencing accounts for about 1% of cases, and about 10% of genetically unresolved cases with an uncertain family history. Hence, identification of mosaicism is important to fully characterize ADPKD populations and provides informed prognostic information.
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