• Childhood Kidney Diseases
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• v.21 no.2
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• pp.165-168
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• 2017

Focal segmental glomerulosclerosis (FSGS) in children, which is a kind of nephrotic syndrome showing steroid resistance, usually progresses to a substantial number of end stage renal disease (ESRD). Although the pathogenesis of primary FSGS is unclear, several recent studies have reported that FSGS is associated with circulating immune factors such as soluble urokinase-type plasminogen activator receptor (suPAR) or anti-CD40 autoantibody. We report a successfully treated case of a 19-year-old female patient who experienced a recurrence of primary FSGS. After the diagnosis of FSGS, the patient progressed to ESRD and received a kidney transplantation (KT). Three days later, recurrence was suspected through proteinuria and hypoalbuminemia. She has been performed plasmapheresis and high dose methylprednisolone pulse therapy and shown remission status without increasing proteinuria for four years after KT. In conclusion, strong immunosuppressive therapy may be helpful for a good prognosis of recurrent FSGS, suppressing several immunologic circulating factors related disease pathogenesis.

• Childhood Kidney Diseases
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• v.13 no.2
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• pp.170-175
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• 2009

Purpose : FSGS do not respond well to any kind of therapy and gradually progress to end-stage renal disease. This study was conducted to investigate the difference of protein expression between MCNS and FSGS as a preliminary study for understanding the pathophysiology of FSGS. Methods : Renal biopsy samples of MCNS and FSGS were obtained, which was diagnosed by one pathologist. They were solubilized with a conventional extraction buffer for protein extraction. The solution was applied on immobilized linear gradient strip gel (pH 4-7) using IPGphor system. Silver staining was carried out according to standard method. Protein identification was done by searching NCBI database using MASCOT Peptide Mass Fingerprint software. Results : The differences in protein expressions between MCNS and FSGS were shown by increased or decreased protein spots. Most prominently expressed spot among several spots in FSGS was isolated and analyzed, one of which was glutathione S-transferase (GST) P1-1, whereas it was not found in MCNS. So GSTP1-1 was considered as the one of the key biomarkers in pathogenesis of FSGS. Conclusion : This result would be helpful in diagnosing FSGS and researching FSGS. Further studies for glutathione S-transferase P1-1 might be necessary to elucidate the mechanisms regarding FSGS.

• Childhood Kidney Diseases
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• v.17 no.1
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• pp.13-18
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• 2013

Podocytopathy is glomerular lesions characterized by podocyte injury. It is observed in various glomerular diseases, but minimal change disease and focal segmental glomerulosclerosis (FSGS) are the prototypes. In this review, morphologic features of podocyte injury and subtypes of FSGS will be reviewed briefly. Effacement of podocyte foot processes is the most common feature of podocyte injury. As podocytic injury progresses, intracytoplasmic vacuoles, subpodocytic cyst, detachment of podocytes from the glomerular basement membrane and apoptosis develop. Glomerular capillary loops in epithelium-denuded area undergo capillary collapse. Synechia and hyalinosis may accompany this lesion. To manifest segmental sclerosis, podocyte loss above a threshold level may be required. Injured podocytes can injure neighboring intact podocytes, and thereby spread injury within the same lobule. FSGS can be categorized into five subtypes by morphologic characteristics; not otherwise specified (NOS), perihilar, cellular, tip, and collapsing types. Each subtype has been reported to show different clinical courses and associated conditions, but there are controversies on its significance. With recent progress in the discovery of genetic abnormalities causing FSGS and plasma permeability factors, we expect to unravel pathophysiology of FSGS and to understand histological sequences leading to FSGS in near future.

• Childhood Kidney Diseases
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• v.4 no.1
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• pp.17-24
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• 2000

Purpose: MCNS is found in approximately $85\%$ of the idiopathic nephrotic syndrome in children and shows good prognosis with initial steroid therapy. However in FSGS, there is poor prognosis with initial therapy and shows higher rate of progression to chronic renal failure and relapse after kindney transplantation. We have experienced 8 patients who were diagnosed as MCNS on initial renal biopsy and then progressed to FSGS on follow-up biopsy. So we have investigated their clinical course and risk factors for transition of MCNS to FSGS. Methods: We conducted a retrospective study with a review of histopathologic findings and clinical manifestations of 296 cases of MCNS and FSGS that were diagnosed from January 1988 to May 1999. We classified them into 3 groups according to the histopathologic finding; MCNS, FSGS, MCNS progressed to FSGS in follow-up biopsy. Results: The number of children was 296 cases comprising 241 cases($81.4\%$) showing MCNS, 8 cases($2.7\%$) transition group, 47 cases($15.9\%$) FSGS. The mean onset age was $6.0{\pm}2.6$years in MCNS, transition group $8.3{\pm}2.3$years, FSGS $7.2{\pm4.3$years, and the gender (M:F) ratio was 3.7:1 in MCNS, 3:1 in transition group, 1.8:1 in FSGS. Comparing the presence of initial hematuria, hypertension,24 hour urine protein, serum albumin, serum creatinine, there were significant difference between the transition group and the FSGS group in the following points; 24hour urine protein $684:342mg/m^2/hr$(P<0.05), serum albumin 1.92: 2.47g/dL(P<0.05), serum cholesterol 494:343mg/dL(P<0.05). Refractoriness to steroid therapy was 13.3$\%$ in MCNS. $12.5\%$ in transition group, $29.6\%$ in FSGS; significantly higher in FSGS(P<0.05). Immunosuppressant therapy was performed in $58.5\%$ of MCNS, $100\%$ in transition group, $80.8\%$ in FSGS; transition group showed significantly higher .ate(P<0.05) comparing with MCNS. Mean number of relapse and duration from onset to first relapse showed no significance difference between these groups. Conclusion: 249 patients with MCNS have been followed and $3.2\%$ (8 patients) of them has shown change in pathologic diagnosis from MCNS to FSCS. The risk factor for transition could not be found. Our results point to the need for a follow-up biopsy to certify the possibility of transition to FSCS in some MCNS cases with refractory cases to steroid therepy, frequent relapsing cases, or in case of no remission in spite of vigorous immunosuppressant therapy.

• Clinical and Experimental Pediatrics
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• v.54 no.1
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• pp.36-39
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• 2011

Bartter syndrome (BS) is a clinically and genetically heterogeneous inherited renal tubular disorder characterized by renal salt wasting, hypokalemic metabolic alkalosis and normotensive hyperreninemic hyperaldosteronism. There have been several case reports of BS complicated by focal segmental glomerulosclerosis (FSGS). Here, we have reported the case of a BS patient who developed FSGS and subsequent end-stage renal disease (ESRD) and provided a brief literature review. The patient presented with classic BS at 3 months of age and developed proteinuria at 7 years. Renal biopsy performed at 11 years of age revealed a FSGS perihilar variant. Hemodialysis was initiated at 11 years of age, and kidney transplantation was performed at 16 years of age. The post-transplantation course has been uneventful for more than 3 years with complete disappearance of BS without the recurrence of FSGS. Genetic study revealed a homozygous p.Trp(TGG)610Stop(TGA) mutation in the CLCNKB gene. In summary, BS may be complicated by secondary FSGS due to the adaptive response to chronic salt-losing nephropathy, and FSGS may progress to ESRD in some patients. Renal transplantation in patients with BS and ESRD results in complete remission of BS.

• Childhood Kidney Diseases
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• v.9 no.1
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• pp.83-90
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• 2005

Focal segmental glomerulosclerosis(FSGS) has been detected in approximately 10% of cases of Idiopathic nephrotic syndrome in children, and exhibits a poor response to initial steroid therapy, as well as a higher rate of progression to chronic renal failure and relapse after kidney transplantation. We describe a case of an eleven year-old boy with steroid-resistant FSGS who exhibited a response to a second trial of cyclosporin h(CsA) therapy. At the age of 26 months, this patient was diagnosed with steroid-resistant FSGS. For 9 years, he had undergone a gauntlet of therapies to induce remission; oral steroids, cyclophosphamide, methylprednisolone(mehyIPd) pulse therapy, CsA, and ibuprofen therapy. Although these therapies failed to induce remission, the patient's renal function remained In the normal range during the nine years of treatment. At the age of ten years, the patient's proteinuria decreased, and complete remission was attained with a second administration of CsA, coupled with a low dose of oral steroids. This patient continues to receive CsA without relapse. Therefore, our major concern involves the possibility of relapse after the discontinuation of CsA therapy Our findings in this case suggest that, in cases of refractory FSGS, if renal insufficiency does not emerge, aggressive therapy for the amelioration of proteinuria should be continuously pursued.

• Childhood Kidney Diseases
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• v.15 no.1
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• pp.38-48
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• 2011

Purpose: Focal segmental glomerulosclerosis (FSGS) is the most common glomerulopathy causing pediatric renal failure. Since specific treatment targeting the etiology and pathophysiology of primary FSGS is yet elusive, the authors explored the pathophysiology of FSGS by transcriptome analysis of the disease using an animal model. Methods: FGS/kist strain, a mouse model of primary FSGS, and RFM/kist strain, as control and the parent strain of FGS/kist, were used. Kidney tissues were harvested and isolated renal cortex was used to extract mRNA, which was run on AB 1700 mouse microarray chip after reverse transcription to get the transcriptome profile. Results: Sixty two genes were differentially expressed in FGS/kist kidney tissue compared to the control. Those genes were related to cell cycle/cell death, immune reaction, and lipid metabolism/vasculopathy, and the key molecules of their networks were TNF, IL-6/4, IFN${\gamma}$, TP53, and PPAR${\gamma}$. Conclusion: This study confirmed that renal cell death, immune system activation with subsequent fibrosis, and lipid metabolism-related early vasculopathy were involved in the pathophysiology of FSGS. In addition, the relevance of methodology used in this study, namely transcriptome profiling, and Korean animal model of FGS/kist was validated. Further study would reveal novel pathophysiology of FSGS for new therapeutic targets.

• Childhood Kidney Diseases
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• v.8 no.2
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• pp.244-249
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• 2004

Obesity-associated focal segmental glomeruloscleropis(OB-FSGS) has been known to progress into advanced renal insufficiency, and its clinicopathological features Include obesity, FSGS lesions with glornerulomegaly and, nephrotic-range proteinuria without edema. A 14 year old girl with Prader-Willi syndrome showed nephrotic-range proteinuria without hypoalbuminemia or edema. The renal biopsy revealed focal segmental glomerulosclerosis together with glomerular hypertrophy and an increased mesangial matrix. We report here a case of OB-FSGS as one of the renal problems of Pradel-Willi syndrome, and we came to the conclusion that Prader-Willi syndrome is one of the Possible disease entities that can lead to renal insufficiency through obesity.

• Childhood Kidney Diseases
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• v.23 no.1
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• pp.7-21
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• 2019

Nephrotic syndrome (NS) is a common chronic glomerular disease in children characterized by significant proteinuria with resulting hypoalbuminemia, edema, and hyperlipidemia. Renal biopsy findings of diffuse foot processes effacement on electron microscopy and minimal change disease, focal segmental glomerulosclerosis (FSGS), or diffuse mesangial proliferation on light microscopy. It has been speculated that circulating permeability factors would be implicated in the pathogenesis of NS because they have been reportedly detected in the sera of patients and in experimental models of induced proteinuria. Moreover, a substantial portion of the patients with primary FSGS recurrence shortly after transplantation. This report reviews the current knowledge regarding the role of circulating permeability factors in the pathogenesis of proteinuria in NS and suggests future targeted therapeutic approaches for NS.

• Childhood Kidney Diseases
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• v.16 no.1
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• pp.21-31
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• 2012

Focal segmental glomerulosclerosis (FSGS) is the name of the primary glomerular disease as well as the terminology to describe the secondary phenomena of any other glomerular diseases. It is characterized by sclerosis, hyalinosis, foam cell infiltration, vacuolar change of podocytes, and halo formation in the glomerulus. Throughout the interstitium, lymphocytes infiltration, tubular atrophy and vascular changes are accompanied. Occasionally, IgM and/or C3 depositions are noted in the sclerotic areas. Electron microscopically, diffuse effacement of foot processes are seen in non-sclerotic area like minimal change disease. Podocyte injury patterns including vacuolar changes are frequently examined. Recently, Columbia group has suggested morphologic classification of FSGS and they demonstrated very good prognosis of tip lesion and poor prognosis of both collapsing and cellular types. However, the pathogenetic classification has been suggested by others; hyperfilteration, podocyte injury, genetic lesions etc. Further studies are necessary to understand and treat this disease.