Marcus R. Benz

Allergic diseases and atopic sensitization in children related to farming and anthroposophic lifestyle – the PARSIFAL study

Background:  The prevalence of allergic diseases has increased rapidly in recent decades, particularly in children. For adequate prevention it is important not only to identify risk factors, but also possible protective factors. The aim of this study was to compare the prevalence of allergic diseases and sensitization between farm children, children in anthroposophic families, and reference children, with the aim to identify factors that may protect against allergic disease.

Bacterial and fungal agents in house dust and wheeze in children: the PARSIFAL study

Background Growing up on a farm and an anthroposophic lifestyle are associated with a lower prevalence of allergic diseases in childhood. This might be related to increased inhalatory exposure to microbial agents.

Mutations in Multiple PKD Genes May Explain Early and Severe Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) is typically a late-onset disease caused by mutations in PKD1 or PKD2, but about 2% of patients with ADPKD show an early and severe phenotype that can be clinically indistinguishable from autosomal recessive polycystic kidney disease (ARPKD). The high recurrence risk in pedigrees with early and severe PKD strongly suggests a common familial modifying background, but the mechanisms underlying the extensive phenotypic variability observed among affected family members remain unknown. Here, we describe severely affected patients with PKD who carry, in addition to their expected familial germ-line defect, additional mutations in PKD genes, including HNF-1β, which likely aggravate the phenotype. Our findings are consistent with a common pathogenesis and dosage theory for PKD and may propose a general concept for the modification of disease expression in other so-called monogenic disorders.

Clinical and Molecular Characterization of Patients with Heterozygous Mutations in Wilms Tumor Suppressor Gene 1

BACKGROUND AND OBJECTIVES The Wilms tumor suppressor gene 1 (WT1) plays an essential role in urogenital and kidney development. Genotype/phenotype correlations of WT1 mutations with renal function and proteinuria have been observed in world-wide cohorts with nephrotic syndrome or Wilms tumor (WT). This study analyzed mid-European patients with known constitutional heterozygous mutations in WT1, including patients without proteinuria or WT. DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS Retrospective analysis of genotype, phenotype, and treatment of 53 patients with WT1 mutation from all pediatric nephrology centers in Germany, Austria, and Switzerland performed from 2010 to 2012. RESULTS Median age was 12.4 (interquartile range [IQR], 6-19) years. Forty-four of 53 (83%) patients had an exon mutation (36 missense, eight truncating), and nine of 53 (17%) had an intronic lysine-threonine-serine (KTS) splice site mutation. Fifty of 53 patients (94%) had proteinuria, which occurred at an earlier age in patients with missense mutations (0.6 [IQR, 0.1-1.5] years) than in those with truncating (9.7 [IQR, 5.7-11.9]; P<0.001) and splice site (4.0 [IQR, 2.6-6.6]; P=0.004) mutations. Thirteen of 50 (26%) were treated with steroids and remained irresponsive, while three of five partially responded to cyclosporine A. Seventy-three percent of all patients required RRT, those with missense mutations significantly earlier (at 1.1 [IQR, 0.01-9.3] years) than those with truncating mutations (16.5 [IQR, 16.5-16.8]; P<0.001) and splice site mutations (12.3 [IQR, 7.9-18.2]; P=0.002). Diffuse mesangial sclerosis was restricted to patients with missense mutations, while focal segmental sclerosis occurred in all groups. WT occurred only in patients with exon mutations (n=19). Fifty of 53 (94%) patients were karyotyped: Thirty-one (62%) had XY and 19 (38%) had XX chromosomes, and 96% of male karyotypes had urogenital malformations. CONCLUSIONS Type and location of WT1 mutations have predictive value for the development of proteinuria, renal insufficiency, and WT. XY karyotype was more frequent and associated with urogenital malformations in most cases.

Novel heterozygous COL4A3 mutation in a family with late-onset ESRD

Thin basement membrane nephropathy (TBMN) and Alport syndrome (ATS) are genetically heterogeneous conditions characterized by structural abnormalities in the glomerular basement membrane (GBM). TBMN presents with hematuria, minimal proteinuria, and normal renal function. Although TBMN is an autosomal dominant disease (COL4A3 and COL4A4), ATS can be inherited X-linked (COL4A5), autosomal recessive, or autosomal dominant (both COL4A3 and COL4A4). The clinical course of TBMN is usually benign, whereas ATS typically results in end-stage renal disease (ESRD). Nevertheless, there is a broad spectrum of clinical phenotypes caused by mutations in COL4A3 or COL4A4. We report an Italian family who presented with hematuria and mild proteinuria. Mutational analysis showed a novel heterozygous mutation p.G291E in exon 15 of the COL4A3 gene. Many different mutations in COL4A3 and COL4A4 that cause TBMN have already been identified, but most genetic variability in these genes has been found to cause autosomal ATS. A valid genotype–phenotype correlation for TBMN or ATS is not yet known. Therefore, it is important to identify new mutations by direct sequencing to clarify their clinical importance, to assess the prognosis of the disease, and to avoid renal biopsy.

Reduced methotrexate clearance and renal impairment in a boy with osteosarcoma and earlier undetected autosomal dominant polycystic kidney disease (ADPKD).

We report a 12-year-old boy with osteoblastic osteosarcoma of the right femur. He was started on chemotherapy according to the EURAMOS/COSS 1 protocol. Chemotherapy with doxorubicin/cisplatin resulted in reversible acute renal failure and methotrexate levels were repeatedly elevated. Family history suggested an autosomal dominant polycystic kidney disease. Genetic testing revealed a novel mutation c.10707_10712del (p.Val3569_3570del) in exon 36 of the PKD1 gene. Patients with autosomal dominant polycystic kidney disease may be at risk for acute renal failure during chemotherapy without signs of renal impairment. A careful family history is important to exclude risk factors for renal impairment before introducing high-dose chemotherapy.

Mein Kind ist Bettnässer

ZusammenfassungKinder, die nachts einnässen, strapazieren nicht nur die Waschmaschinen und die Nerven ihrer Eltern, sie leiden vor allem auch selbst unter den „Überschwemmungen“. Hier können Sie allen Beteiligten Mut machen: Klingelgeräte sorgen bei primärer Enuresis in 70% der Fälle langfristig für trockene Nächte. Bevor Sie zum Rezeptblock greifen, sollten Sie jedoch andere Ursachen für das Einnässen ausschließen. Wie Sie vorgehen, zeigt unser Autor in einem praxisnahen Algorithmus. In children with nocturnal bedwetting, the basic diagnostic evaluation to differentiate between monosymptomatic enuresis and organic or functional urinary incontinence is mandatory. When the diagnosis of monosymptomatic enuresis is set, a stepped therapeutic program is available, in which alarm/behavior therapy has a central role. Drug therapy of monosymptomatic enuresis in childhood is an established option and is reserved for certain indications.

Initial treatment of steroid-sensitive idiopathic nephrotic syndrome in children with mycophenolate mofetil versus prednisone: protocol for a randomised, controlled, multicentre trial (INTENT study)

Introduction Idiopathic nephrotic syndrome is the most common glomerular disease in childhood with an incidence of 1.8 cases per 100 000 children in Germany. The treatment of the first episode implies two aspects: induction of remission and sustainment of remission. The recent Kidney Disease Improving Global Outcomes, American Academy of Pediatrics and German guidelines for the initial treatment of the first episode of a nephrotic syndrome recommend a 12-week course of prednisone. Despite being effective, this treatment is associated with pronounced glucocorticoid-associated toxicity due to high-dose prednisone administration over a prolonged period of time. The aim of the INTENT study (Initial treatment of steroid-sensitive idiopathic nephrotic syndrom in children with mycophenolate mofetil versus prednisone: protocol for a randomised, controlled, multicentre trial) is to show that an alternative treatment regimen with mycophenolic acid is not inferior regarding sustainment of remission, but with lower toxicity compared with treatment with glucocorticoids only. Methods and design The study is designed as an open, randomised, controlled, multicentre trial. 340 children with a first episode of steroid-sensitive nephrotic syndrome and who achieved remission by a standard prednisone regimen will be enrolled in the trial and randomised to one of two treatment arms. The standard care group will be treated with prednisone for a total of 12 weeks; in the experimental group the treatment is switched to mycophenolate mofetil, also for a total of 12 weeks in treatment duration. The primary endpoint is the occurrence of a treated relapse within 24 months after completion of initial treatment. Ethics and dissemination Ethics approval for this trial was granted by the ethics committee of the Medical Faculty of the University of Heidelberg (AFmu-554/2014). The study results will be published in accordance with the Consolidated Standards of Reporting Trials statement and the Standard Protocol Items: Recommendations for Interventional Trials guidelines. Our findings will be submitted to major international paediatric nephrology and general paediatric conferences and submitted for publication in a peer-reviewed, open-access journal. Trial registration number DRKS0006547; EudraCT2014-001991-76; Pre-result. Date of registration 30 October 2014; 24 February 2017.

No Impact of the Analytical Method Used for Determining Cystatin C on Estimating Glomerular Filtration Rate in Children

Background Measurement of inulin clearance is considered to be the gold standard for determining kidney function in children, but this method is time consuming and expensive. The glomerular filtration rate (GFR) is on the other hand easier to calculate by using various creatinine- and/or cystatin C (Cys C)-based formulas. However, for the determination of serum creatinine (Scr) and Cys C, different and non-interchangeable analytical methods exist. Given the fact that different analytical methods for the determination of creatinine and Cys C were used in order to validate existing GFR formulas, clinicians should be aware of the type used in their local laboratory. In this study, we compared GFR results calculated on the basis of different GFR formulas and either used Scr and Cys C values as determined by the analytical method originally employed for validation or values obtained by an alternative analytical method to evaluate any possible effects on the performance. Methods Cys C values determined by means of an immunoturbidimetric assay were used for calculating the GFR using equations in which this analytical method had originally been used for validation. Additionally, these same values were then used in other GFR formulas that had originally been validated using a nephelometric immunoassay for determining Cys C. The effect of using either the compatible or the possibly incompatible analytical method for determining Cys C in the calculation of GFR was assessed in comparison with the GFR measured by creatinine clearance (CrCl). Results Unexpectedly, using GFR equations that employed Cys C values derived from a possibly incompatible analytical method did not result in a significant difference concerning the classification of patients as having normal or reduced GFR compared to the classification obtained on the basis of CrCl. Sensitivity and specificity were adequate. On the other hand, formulas using Cys C values derived from a compatible analytical method partly showed insufficient performance when compared to CrCl. Conclusion Although clinicians should be aware of applying a GFR formula that is compatible with the locally used analytical method for determining Cys C and creatinine, other factors might be more crucial for the calculation of correct GFR values.

Erkrankungen der Niere und ableitenden Harnwege

Fehlbildungen der Niere und der ableitenden Harnwege gehoren zu den haufigsten Fehlbildungen uberhaupt. Durch die sich entwickelnde Ureterknospe wird im metanephrogenen Blastem (Metanephros=Nachniere) die Ausbildung der Glomeruli und Tubuli induziert, die dann Anschluss an die sich aus dem Ureter entwickelnden harnableitenden Strukturen (Sammelrohre, Nierenkelche, Harnleiter) finden. Die Nephrogenese mit Ausbildung von Glomeruli ist in der 34.–36. SSW abgeschlossen, danach schliesen sich noch Grosenwachstum und Ausreifung der angelegten Strukturen an. Die Nieren nehmen ihre Funktion zwischen der 11. und der 13. SSW auf, relevante Urinmengen werden etwa ab der 20. SSW produziert, sodass dann ein mogliches Oligo- oder Polyhydramnion renaler Ursache apparent wird.