Renal microangiopathies and membranoproliferative GN (MPGN) can manifest similar clinical presentations and histology, suggesting the possibility of a common underlying mechanism in some cases. Here, we performed homozygosity mapping and whole exome sequencing in a Turkish consanguineous family and identified DGKE gene variants as the cause of a membranoproliferative-like glomerular microangiopathy. Furthermore, we identified two additional DGKE variants in a cohort of 142 unrelated patients diagnosed with membranoproliferative GN. This gene encodes the diacylglycerol kinase DGK«, which is an intracellular lipid kinase that phosphorylates diacylglycerol to phosphatidic acid. Immunofluorescence confocal microscopy demonstrated that mouse and rat Dgk« colocalizes with the podocyte marker WT1 but not with the endothelial marker CD31. Patch-clamp experiments in human embryonic kidney (HEK293) cells showed that DGK« variants affect the intracellular concentration of diacylglycerol. Taken together, these results not only identify a genetic cause of a glomerular microangiopathy but also suggest that the phosphatidylinositol cycle, which requires DGKE, is critical to the normal function of podocytes.

Genetic differences may accompany the phenotypic differences found in the Turkish group. Although larger numbers of patients are clearly needed to verify this, we suggest that the G-->A -308 polymorphism may be operative in defining disease outcome in selected groups.

Acute tumour lysis syndrome (ATLS) is a well recognised complication of treatment of a variety of malignant disorders. It commonly occurs in patients with non-Hodgkin's lymphoma (NHL) and acute lymphoblastic leukaemia (ALL) with the administration of combined cytotoxic chemotherapy. It is rarely reported after single-agent corticosteroid therapy. We present two children with acute lymphoblastic leukaemia of T-cell lineage who developed acute tumour lysis syndrome after a single dose of prednisolone, and methylprednisolone at the beginning of the induction chemotherapy. In the first case (an 11-yr-old) ATLS had occurred after an oral dose of prednisolone as small as 12 mg and within 18 h. The second case was a 14-yr-old boy with ALL who developed ATLS following a single dose of methylprednisolone. A few similar cases in the English literature are summarised in the report. These cases indicate that acute tumour lysis syndrome may occur after a single dose of corticosteroids. One should be aware of this potentially life-threatening complication especially while prescribing corticosteroids to patients with NHL and leukaemia.

Background. Crescentic glomerulonephritis (CGN) is a rapidly progressive and rare cause of glomerulonephritis in childhood. The aim of this study is to evaluate demographic data of children with crescentic glomerulonephritis, to classify the etiologies and to investigate the correlation between the severity of kidney disease and the expression of CD163+ macrophages. Methods.Between the years 2000 and 2016 in a single center, patients under 18 years of age with kidney biopsies containing crescents were included in the study. A total of 88 children were enrolled. The expression of CD163 in kidney tissues was detected by immunohistochemistry in 61 patients. Clinical features and outcome were collected from their medical records.Results. The most common etiology was Henoch-Schönlein purpura (HSP) nephritis/Immunglobulin A vasculitis (26.1%), followed by lupus nephritis (22.7%) and idiopathic crescentic glomerulonephritis (18.2%). CD163 positive cell counts in patients with GFR levels less and more than 60 ml/min/1.73 m 2 at their last visit were 7.6±6.6 cells vs. 2.0±3.0 cells (p=0.057) per one glomerulus and 52.2±18.2 cells/hpf vs. 33.3±10.0 cells/hpf (p <0.05) in tubulointerstitium, respectively. Tubulointerstitital CD163+ cells were also found to be higher in patients with end stage kidney disease than complete and partial responders (68 cells/hpf vs 39 cells/hpf, p<0.05).Conclusions. CD163 positive cell counts, particularly in tubulointerstitial areas, have been associated with poor prognosis of CGN.

Popliteal cysts occur commonly both in normal and arthritic knees. Most cysts are formed by distension of the medially situated semimembranosus bursa. Herein, we describe three children with juvenile idiopathic arthritis and ruptured popliteal cysts which produced leg complaints. Ultrasound and magnetic resonance imaging were performed in the diagnosis of all cases for better evaluation of the anatomic characteristics of the cysts. In all cases, pain and swelling reduced and t hen disappeared with conservative management. In children with juvenile idiopathic arthritis who present with calf pain and swelling of leg, ruptured Baker' s cyst should be considered in the diagnosis.