Disparities in dialysis treatment and outcomes for Dutch and Belgian children with immigrant parents

BACKGROUND: In Belgium and the Netherlands, up to 40% of the children on dialysis are children with immigrant parents of non-Western European origin (non-Western). Concerns exist regarding whether these non-Western patients receive the same quality of care as children with parents of Western European origin (Western). We compared initial dialysis, post-initial treatment, and outcomes between non-Western and Western patients on dialysis. METHODS: All children <19 years old on chronic dialysis in the Netherlands and Belgium between September 2007 and May 2011 were included in the study. Non-Western patients were defined as children of whom one or both parents were born in non-Western countries. RESULTS: Seventy-nine of the 179 included patients (44%) were non-Western children. Compared to Western patients, non-Western patients more often were treated with hemodialysis (HD) instead of peritoneal dialysis (PD) as first dialysis mode (52 vs. 37%, p = 0.046). Before renal transplantation, non-Western patients were on dialysis for a median (range) of 30 (5-99) months, vs. 15 (0-66) months in Western patients (p = 0.007). Renal osteodystrophy was diagnosed in 34% of non-Western vs. 18% of Western patients (p = 0.028). The incidence rate ratio [95% confidence interval] for acute peritonitis was 2.44 [1.43-4.17] (p = 0.032) for non-Western compared to Western patients. CONCLUSIONS: There are important disparities between children on chronic dialysis with parents from Western European origin and those from non-Western European origin in the choice of modality, duration, and outcomes of dialysis therapy

Understanding renal posttransplantation anemia in the pediatric population

Advances in renal transplantation management have proven to be beneficial in improving graft and patient survival. One of the properties of a well-functioning renal allograft is the secretion of adequate amounts of the hormone erythropoietin to stimulate erythropoiesis. Posttransplantation anemia (PTA) may occur at any point in time following transplantation, and the cause is multifactoral. Much of our understanding of PTA is based on studies of adult transplant recipients. The limited number of studies that have been reported on pediatric renal transplant patients appear to indicate that PTA is prevalent in this patient population. Erythropoietin deficiency or resistance is commonly associated with iron deficiency. An understanding of the risk factors, pathophysiology and management of PTA in the pediatric renal transplant population may provide guidelines for clinicians and researchers in the pursuit of larger prospective randomized control studies aimed at improving our limited knowledge of PTA. Recognition of PTA through regular screening and evaluation of the multiple factors that may contribute to its development are recommended after transplantation

Cobalamin disorder Cbl-C presenting with late-onset thrombotic microangiopathy.

Two siblings, a boy age 12 and his sister age 4 years, presented with proteinuria and hematuria, hypertension, and chronic hemolytic anemia. At age 13 years, the boy developed an episode of severe hypertensive encephalopathy and transient renal failure. Both children are attending normal school, have no neurologic symptoms, and only minimal pigmentary retinal abnormalities. Renal biopsy showed a chronic thrombotic microangiopathic nephropathy. Both patients had hyperhomocysteinemia and mild methylmalonic aciduria. Fibroblasts showed decreased cobalamin uptake, reduced methyl- and adenosyl-cobalamin formation, and deficient incorporation of formate and propionate, compatible with the Cbl-C complementation group, but milder than that found in cells from most patients. Both patients and their father carry a balanced reciprocal translocation. Parenteral hydroxycobalamin treatment reduced the homocysteine levels, and methylmalonic acid disappeared. Increasing the dosage of hydroxycobalamin from 1 to 2.5, then 5 mg daily together with betaine, further reduced homocysteine levels (boy from 118 to 23 microM and girl from 59 to 14 microM). With this treatment, hemolysis has stopped, hematuria has disappeared, proteinuria has almost normalized, and creatinine clearance has been stable. Investigations for chronic thrombotic microangiopathy should include testing for this unusual but treatable disorder, regardless of age of presentation

An unusual presentation of Denys-Drash syndrome due to bigenic disease

Item does not contain fulltextWe report a case of Denys-Drash syndrome (DDS) in a 3-month-old girl presenting with bilateral renal cortical cysts mimicking polycystic kidney disease. Genetic analysis revealed a de novo heterozygous missense mutation c.1186G>A (p.Asp396Asn) in the WT1 gene, confirming the diagnosis of DDS. Because multiple renal cysts have never been reported in DDS, we explored several genes responsible for these renal manifestations, such as HNF-1beta, PAX2, PKD1, and PKD2. Remarkably, we identified a heterozygous missense variant c.12439A>G (p.Lys4147Glu) in the PKD1 gene. The same variant was found in the patient's mother, who had no renal cysts, and in the grandfather, who had several renal cysts. Mutation prediction programs classified the c.12439A>G variant as being "likely pathogenic." We hypothesize that the severe cystic phenotype in the index patient could be due to the WT1 mutation, enhancing pathogenicity of the "hypomorph" PKD1 allele. A possible role for Wilms tumor suppressor 1 (WT1) in renal cyst development should be considered. From a conceptual point of view, this case shows that an unusual presentation of a known genetic syndrome might point to bigenic inheritance, with unexpected interference of mutated genes causing an uncommon clinical phenotype