These results support more liberal use of living-related donors for renal transplantation of children with FSGS and ESRD, considering the shortage of cadaveric donors in our society and relatively good efficacy of the early and intensive PE+CPM therapy for early recurrent nephrotic syndrome.

Although genetic defect of complement factor H (CFH) is a common cause of atypical hemolytic uremic syndrome (aHUS), development of autoantibodies to CFH (CFH-Ab) is also known to be an acquired cause of aHUS. Recently, a correlation between the development of CFH-Ab and the deficiency of the CFH-related proteins, CFHR1 and CFHR3, was identified. In this study, plasma complement profiles were measured and genetic analysis of the CFH, CFI, MCP, CFHR1, and CFHR3 genes were performed in three female patients diagnosed with aHUS with positive CFH-Ab. Acute stage plasmas of all the three patients revealed low C3, low or low-normal CFH antigenic levels, and high titers of CFH-Ab. All the patients also showed complete plasma CFHR1 deficiency and homozygous genomic deletion of CFHR1/CFHR3, but none had CFH, CFI, or MCP mutations. All the patients were treated with plasmapheresis, and two patients required additional immunosuppressive therapy. These patients had a novel subgroup of aHUS characterized by a combination of genetic (a homozygous deletion of CFHR1/CFHR3) and acquired (development of CFH-Ab) factors. Patients with this disease may need intensive immunosuppressive therapy in addition to plasmapheresis. Screening for CFH-Ab and the CFHR1/CFHR3 deficiency should be included in the diagnostic tests for patients with aHUS. (Pediatr Res 66: 336-340, 2009)

X-linked hypophosphatemic rickets (XLH), autosomal dominant hypophosphatemic rickets, hereditary hypophosphatemic rickets with hypercalciuria, and tumor-induced osteomalacia share clinical and biochemical features, and are collectively referred to as hypophosphatemic rickets (HR). Recently, the molecular bases of HR were elucidated. A review of medical records and mutational analyses of the PHEX and FGF23 genes were performed on 17 unrelated Korean children with HR. The male-to-female ratio was 3:14, and 5 patients were familial. Initial laboratory tests revealed typical features of HR. Seven different PHEX mutations were detected in 8 patients: 2 missense mutations, 2 nonsense mutations, and 3 short deletions. No functional FGF23 mutation was detected in any patient. Patients with the PHEX mutation tended to have more severe skeletal disease than those without. Of the patients with this mutation, no genotype-phenotype correlation and no gene dosage effect were noted. Treatment with vitamin D and phosphate resulted in only a partial growth improvement in most cases, and was frequently complicated by hypercalciuria, hypercalcemia, nephrocalcinosis, or hyperparathyroidism. Renal glycosuria was detected in six cases and was associated with more severe skeletal disease. We conclude that current HR treatment is not fully safe or effective, and that close monitoring of treatment effectiveness and for complications should be performed during long-term treatment.No genotype-phenotype correlation in XLH was detected in this study, but a large-scaled study on this topic is warranted. The large proportion of patients with a normal genetic study suggests the possibility of other causative gene(s HR is defined as a group of rachitic bone diseases associated with chronic hypophosphatemia, which results from defects in the renal tubular reabsorption of filtered phosphate (1-8). Clinically, XLH, ADHR, HHRH, and TIO can be categorized as HR (1-8).XLH is the most common form of hereditary HR (2-6) and is caused by loss-of-function mutations in the PHEX gene (phosphate regulating gene with homologies to endopeptidases on the X chromosome). On the other hand, ADHR is far less common than XLH (2-6), and is associated with a gain-offunction mutation in the FGF23 gene encoding FGF23. The mutant FGF23 molecule is resistant inactivation by proteolytic cleavage (2,(5)(6)(7)(8)(9)(10)(11)(12). Moreover, TIO is an acquired form of HR, which is caused by a variety of benign primitive mesenchymal tumors that secrete FGF23 (2,7,13). HHRH is a rare hereditary disease and its underlying pathogenesis remains to be elucidated.Several studies of the molecular defects in XLH, ADHR, and TIO support a model of a common pathogenetic mechanism in these three diseases (2,6,14). In this model, FGF23 has been suggested to be the main circulating phosphaturic factor (2,6,14), and the circulating level of FGF23 is determined in part by the rate of its proteolytic cleavage by PHEX protease (9,13,15). The common abnormality shared by loss-of-function mutation...

To date, two responsible genes for the development of Dent disease have been identified: CLCN5 and OCRL1. In this study, genotype-phenotype correlations were studied in patients with Dent disease and those with Lowe syndrome. Among the 12 boys with a phenotype typical of Dent disease, nine had a mutation in CLCN5 (Dent disease 1), two had a mutation in OCRL1 (Dent disease 2), and one had no mutations in either gene. All seven boys with a clinical diagnosis of Lowe syndrome had a mutation in OCRL1. Patients with Lowe syndrome showed more frequent hypophosphatemia/rickets and more prominent tubular proteinuria than patients with Dent disease 1, and patients with Dent disease 2 had higher degree of tubular proteinuria and hypercalciuria than patients with Dent disease 1. Additionally, one patient with Dent disease 2 showed a mild degree of developmental delay, elevated serum muscle enzyme levels, and cryptorchidism. In this study, the genetic heterogeneity in Dent disease and the phenotypic heterogeneity in Lowe syndrome were confirmed. In patients with Dent disease, the presence of the above-mentioned extrarenal manifestations indicates that it is more likely that the patient is affected by Dent disease 2 than by Dent disease 1.

A total of 1,044 school children identified with hematuria and/or proteinuria during a mass school urine screening test were referred to pediatric nephrologists at 13 hospitals in Korea. These children had isolated hematuria (IH) (60.1%), isolated proteinuria (IP) (26.4%: transient, 19.6%; orthostatic, 4.9%; persistent, 1.9%) or combined hematuria and proteinuria (CHP) (13.5%). The patient's history, physical examination, laboratory tests, kidney ultrasound and Doppler ultrasonography were obtained. Renal biopsies were performed on 113 children who showed severe proteinuria, hypertension, abnormal renal function, family history of chronic renal disease, systemic diseases or persistent hematuria and/or proteinuria for more than 12 months. IgA nephropathy (IgAN), thin basement membrane nephropathy (TBMN), membranoproliferative glomerulonephritis (MPGN), focal segmental glomerulosclerosis (FSGS), other GN, Alport syndrome and lupus nephritis were detected. IgAN and TBMN were the most common causes in the CHP group and IH group, respectively. Abnormal findings on the renal ultrasound with or without Doppler ultrasonography were noted in 147 cases (suspected nutcracker phenomenon, 65; increased parenchymal echogenicity, 40; hydronephrosis, 15). This study showed that the use of a mass school urine screening program can detect chronic renal disease in its early stage and recommends that more attention should be paid to identifying those children with CHP and massive proteinuria. A school urine screening program can detect chronic renal disease in its early stage. When mass screening is used, the initial aggressive diagnostic procedures such as renal biopsy are not needed. In addition, a regular follow-up for those children with IH and IP is certainly warranted.