Joo Hoon Lee

Asan Medical Center, Sŏul, Seoul, South Korea

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Publications (27)53.2 Total impact

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    ABSTRACT: Purposes To evaluate the mineral and bone disorders in children with chronic kidney disease (CKD) stage I to V predialysis. Methods Pediatric subcohort of KNOW-CKD (KoreaN cohort study for Outcome in patients With CKD) enrolled children (younger than 20 years) with CKD stage I-V (pre-dialysis) from five major pediatric nephrology centers in Korea and collected medical data associated with CKD-mineral and bone disorder. Results Total number of 300 patients (male:female=199:101) was included in this study. Serum phosphorus (mean ± standard deviation 4.89±0.75, 4.6±0.83, 4.63±0.85, 5.13±1.37, 5.35±1.2 from CKD stage I to V, p=0.0002), fibroblast growth factor (FGF)-23 (32.29±42.04, 41.33±41.00, 70.68±121.06, 67.9±66.95, 121.74±139.36, p=0.0030) and the prevalence of hyperphosphatemia (8.51%, 10.64%, 25.53%, 25.53%, 29.79%, p=0.010) increased as CKD progressed. Intact parathyroid hormone (iPTH) increased (40.84±40.37, 44.13±20.2, 78.93±65.21, 181.39±183.86, 313.85±324.95, p<0.001) and serum 1,25D3 level decreased (47.52±21.32, 37.43±12.26, 36.86±25.97, 28.29±15.81, 34.11±21.34, p<0.001) significantly as CKD aggravated. Serum iPTH (r=−0.608, p<0.0001) and FGF-23 (r=−0.4943, p<0.0001) showed negative correlation whereas 1,25D3 (r=0.3288, <0.0001) showed positive correlation with glomerular filtration rate. FGF-23 showed positive correlation with serum phosphorus (r=0.3342, p<0.0001), iPTH (r=0.3214, p<0.0001) and proteinuria (r=0.3609, p<0.0001), and negative correlation with urine phosphorus (r=−0.2597, p=0.0006). The prevalence of patients with increased alkaline phosphatase level increased significantly as CKD progressed (5.66%, 15.09%, 39.62%, 16.98%, 22.64%, p=0.042), which was due to increased prevalence of hyperparathyroidism (p<0.001). Active form vitamin D (0%, 3.77%, 11.88%, 40.74%, 68.89%, p<0.0001), calcium (2.13%, 0%, 9.90%, 4.44%, 62.22%, p<0.0001) and non-calcium phosphorous binders (0%, 0%, 0%, 0%, 13.33%, p<0.0001) were prescribed significantly more often in advanced CKD. Calcium x phosphorus was significantly increased in advanced CKD (11.59%, 17.39%, 28.26%, 21.01%, 21.74%, p=0.002). Conclusion As CKD progressed, hyperphosphatemia, hyperparathyroidism and 1,25D3 deficiency increased, serum FGF-23 level increased and urinary phosphorus excretion decreased in children with CKD stage I to V predialysis.
    Kidney Research and Clinical Practice. 01/2014; 33(2):A3–A4.
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    ABSTRACT: Although asymptomatic gross hematuria (GHU) is relatively common in children, its causes and clinical outcomes are not clearly defined. Children with asymptomatic GHU were examined and work-up was performed. Patients with recurrent GHU with proteinuria, or significant proteinuria, were considered for renal biopsy. The male:female ratio of all patients was 190:75, and the median age at onset of GHU was 6.4 years. Patients were grouped according to abnormalities on initial evaluation as follows: idiopathic (50%), proteinuria (21%), hypercalciuria (14%), sonographic abnormality (7%), hypocomplementemia (4%), familial (3%), and bleeding tendency (2%). Of patients with idiopathic GHU, 38% had a single episode, and of these, 34% had persistent microscopic hematuria, which resolved on follow-up., Late onset proteinuria was accompanied in 11% of patients with recurrent GHU. Nutcracker syndrome was diagnosed in one patient with recurrent idiopathic GHU. Of patients with recurrent GHU, 89% had no proteinuria on follow-up, and GHU and microscopic hematuria resolved in 97% and 89%, respectively. Our work-up protocol was useful for diagnosis and follow-up planning. Asymptomatic GHU in children was most commonly the idiopathic form. Overall, long-term prognosis appears to be benign; however, careful follow-up is essential.
    Nephrology 11/2013; · 1.69 Impact Factor
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    ABSTRACT: BACKGROUND: Health-related quality of life (HRQOL) is an essential subject for children with end-stage renal disease (ESRD) and their families. METHODS: We performed a cross-sectional investigation of HRQOL in children undergoing renal replacement therapies, such as dialysis and renal transplantation, using the 34-item Pediatric Quality of Life Inventory 3.0 End-Stage Renal Disease (PedsQL 3.0 ESRD) module. We assessed 92 ESRD patients aged 2-18 from four Korean university hospitals. RESULTS: The male:female ratio was 44:48, and the most common cause of ESRD was chronic glomerulonephritis. Fifty-five children were treated by dialysis, and 37 received renal transplantation. Transplant patients had better HRQOL than dialysis patients in two domains in parent proxy reports: "About my kidney disease" and "Worry." In child self-reports, transplant patients had better HRQOL than dialysis patients in one domain: Treatment problems. However, there were no significant differences in total QOL scores between peritoneal dialysis (PD) and transplant patients in child self-reports. In addition, there were differences in the ESRD module scores between child self- and parent proxy reports. Children usually reported better QOL than their parents. Child self-reports showed significantly higher QOL scores than parent proxy reports in the domains of General fatigue, Family & peer interaction, and Worry. Children on PD self-reported a significantly higher QOL than children on hemodialysis (HD). CONCLUSIONS: The PedsQL 3.0 ESRD module may be useful as an ESRD-specific instrument to evaluate HRQOL in children; however, a larger, longitudinal prospective study is warranted.
    Pediatric Nephrology 07/2012; · 2.94 Impact Factor
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    ABSTRACT: Health-related quality of life is a very important issue in children with end-stage renal disease and their family. Moreover, this can be a lifelong problem. In this study, we performed a cross-sectional investigation of the health-related quality of life in Korean children, undergoing renal replacement therapies, such as dialysis and renal transplantation. We validated the Korean version of the PedsQL 3.0 End-Stage Renal Disease Module by comparing with the PedsQL 4.0 Generic Core Scales. A total of 92 pediatric patients with end-stage renal disease, aged 2-18 year old, were enrolled in four teaching hospitals in Korea. The module was acceptable for both parent proxy-report and child self-report. The response rate was acceptable, since no reminders were delivered. A large proportion of the responders answered > 90% of the items, which suggests a good face validity. The PedsQL 4.0 Generic Core Scales and the PedsQL 3.0 End-Stage Renal Disease Module showed minimal missing values in the current study, which supported feasibility. The validation analyses revealed acceptable floor and ceiling effects and an acceptable construct validity. The PedsQL 3.0 End-stage Renal Disease Module may be useful as an end-stage renal disease -specific instrument in the evaluation of the health-related quality of life in Korean children; however, a larger, longitudinal prospective study is needed.
    Health and Quality of Life Outcomes 06/2012; 10:59. · 2.27 Impact Factor
  • Yoon Jung Lee, Joo Hoon Lee, Young Seo Park
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    ABSTRACT: We prospectively determined the risk factors for renal scar formation after the first episode of acute pyelonephritis as confirmed on dimercapto-succinic acid scintigraphy in children younger than 1 year. A total of 213 infants with acute pyelonephritis were enrolled in the study. Infants with urological abnormalities other than vesicoureteral reflux were excluded from analysis. Followup scanning was performed 6 months after acute pyelonephritis and voiding cystourethrography was performed after the acute phase of infection. Possible risk factors were evaluated including gender, peak fever, duration of fever before and after treatment with antibiotics, white blood cell count, C-reactive protein concentration, presence of vesicoureteral reflux and reflux grade. Six months after acute pyelonephritis 37 of 213 (17.4%) infants and 41 of 248 (16.5%) renal units with acute photon defects on initial dimercapto-succinic acid scintigraphy had renal scars. The rates of scar formation were significantly higher in infants with vesicoureteral reflux than in those without (39.4% vs 7.5%, p <0.001, OR 9.433) and in renal units with vesicoureteral reflux than in those without (39.4% vs 8.2%, p <0.001, OR 7.237). Renal scar formation was related to reflux grade (none-8.2%, grade I-20%, grade II-22.7%, grade III-40%, grade IV-70%, grade V-55.6%, p <0.001) but not to any other clinical or laboratory variables. The presence of vesicoureteral reflux was the only independent risk factor for renal scar formation after acute pyelonephritis in infants. The prevalence of renal scarring was significantly correlated with reflux grade. Voiding cystourethrography is necessary in infants after the first acute pyelonephritis episode is confirmed on dimercapto-succinic acid renal scintigraphy.
    The Journal of urology 03/2012; 187(3):1032-6. · 4.02 Impact Factor
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    ABSTRACT: We report a patient with immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome with a novel splicing mutation of the FOXP3 gene. The patient is a boy, born at 39 + 2 weeks gestation with a birth weight of 3,280 g. The family history was unremarkable. He was well until 11 months of age, when he was diagnosed with type 1 diabetes mellitus. The level of urine C-peptide was 0.58 μg/day (normal range, 44-116 μg/day). Glutamic acid decarboxylase autoantibody was not detected, but a high level of anti-insulin antibody (50 IU/mL; normal range, <5 IU/mL) was noted. This patient presented with unusual clinical features, including pure red cell aplasia, membranous glomerulopathy, and posterior reversible encephalopathy syndrome after a vaccination against influenza A H1N1 virus. The diagnosis of IPEX was made when the patient was 11 years old, which is quite late compared with typical cases. Conclusion: Although IPEX syndrome is usually a disease of infancy, it should not be ruled out solely on the basis of age. IPEX presentation is so variable that it should be suspected in a male child with one or more autoimmune disorders and severe infections.
    European Journal of Pediatrics 12/2011; 170(12):1611-5. · 1.91 Impact Factor
  • American Journal of Kidney Diseases 12/2011; 58(6):1042-3. · 5.29 Impact Factor
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    ABSTRACT: Bartter syndrome (BS) is clinically classified into antenatal or neonatal BS (aBS) and classic BS (cBS) as well as five subtypes based on the underlying mutant gene; SLC12A1 (BS I), KCNJ1 (BS II), CLCNKB (BS III), BSND (BS IV) and CASR (BS V). Clinico-genetic features of a nationwide cohort of 26 Korean children with BS were investigated. The clinical diagnosis was aBS in 8 (30.8%), cBS in 15 (57.7%) and mixed Bartter-Gitelman phenotype in 3 cases (11.5%). Five of eight patients with aBS and all 18 patients with either cBS or mixed Bartter-Gitelman phenotype had CLCNKB mutations. Among the 23 patients (46 alleles) with CLCNKB mutations, p.W610X and large deletions were detected in 25 (54.3%) and 10 (21.7%) alleles, respectively. There was no genotype-phenotype correlation in patients with CLCNKB mutations. Twenty-three (88.5%) of the 26 BS patients involved in this study had CLCNKB mutations. The p.W610X mutation and large deletion were two common types of mutations in CLCNKB. The clinical manifestations of BS III were heterogeneous without a genotype-phenotype correlation, typically manifesting cBS phenotype but also aBS or mixed Bartter-Gitelman phenotypes. The molecular diagnostic steps for patients with BS in our population should be designed taking these peculiar genotype distributions into consideration, and a new more clinically relevant classification including BS and Gitelman syndrome is required.
    Nephrology Dialysis Transplantation 08/2011; 27(4):1516-21. · 3.37 Impact Factor
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    ABSTRACT: MYH9-related disorders are a group of autosomal, dominantly inherited disorders caused by mutations of the MYH9 gene, which encodes the non-muscle myosin heavy chain IIA (NMMHC-IIA). May-Hegglin anomaly and Sebastian, Fechtner, and Epstein syndromes belong to this group. Macrothrombocytopenia is a common characteristic associated with MYH9-related disorders, and basophilic cytoplasmic inclusion bodies in leukocytes (Döhle-like bodies), deafness, cataracts, and glomerulopathy are also found in some patients. In this study, renal manifestations of 7 unrelated Korean patients with MYH9-related disorders were analyzed. Of a total of 7 patients, 4 had disease-related family histories. One familial case had a mutation in the tail domain of NMMHC-IIA and showed milder renal involvement with preserved renal function by his 30s. Among the 3 familial cases without renal involvement, 2 had mutations in the tail domain of NMMHC-IIA and 1 had a mutation in the motor domain. The remaining 3 sporadic cases had severe renal involvement with rapid progression to end-stage renal disease and mutations located in the motor domain. In summary, mutations in the motor domain of NMMHC-IIA and negative family history were associated with severe renal involvement in patients with MYH9-related disorders. These results are in agreement with those of previous reports.
    Pediatric Nephrology 04/2011; 26(4):549-55. · 2.94 Impact Factor
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    Korean Journal of Pediatrics 01/2009; 52(4).
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    Journal of the Korean Society of Pediatric Nephrology 01/2009; 13(2).
  • Joo Hoon Lee
    Korean Journal of Pediatrics 01/2009; 52(10).
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    Journal of the Korean Society of Pediatric Nephrology 01/2009; 13(2).
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    ABSTRACT: Mutations in the SLC22A12 gene, which encodes a uric acid transporter, URAT1, are associated with renal hypouricaemia. This study was designed to measure serum uric acid (Sua) levels and allele frequencies of two common mutations in SLC22A12, W258X and R90H, in healthy Korean subjects. A total of 909 unrelated Korean adults (male : female, 1:1.23; mean age, 48.4 +/- 11.0 years) were recruited among those who had taken a routine health check-up in a health centre in 2003. None of them had hypertension, diabetes mellitus, kidney diseases or liver diseases. Genotyping for W258X and R90H was performed using the TaqMan method. The prevalences of hyperuricaemia (Sua levels, >416 micromol/L) and hypouricaemia (Sua levels, <178 micromol/L) were 4.6% and 3.3%, respectively. A marked male preponderance in the hyperuricaemic group was noted, and the men revealed higher Sua than the women. The Sua showed a positive correlation with serum creatinine level and blood pressure. In the hypouricaemic group, the allele frequencies of W258X and R90H were 11.7% and 6.7%, respectively, and the proportion of subjects with one or both of the mutant alleles was 33.3%. Hyperuricaemic subjects never had either mutation. The W258X and/or R90H mutations in the SLC22A12 gene are one of the major factors responsible for hypouricaemia, and one-third of the hypouricaemic subjects had one or both of the mutant alleles.
    Nephrology 11/2008; 13(8):661-6. · 1.69 Impact Factor
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    ABSTRACT: Fabrazyme has been widely used for treatment of Fabry disease since its approval by the U.S. Food and Drug Administration in 2003. This study was undertaken to assess the short-term efficacy and safety of enzyme replacement therapy (ERT) for Fabry disease in Korea. Eight male patients and three female symptomatic carriers aged 13 to 48 yr were included. Fabrazyme was administered by intravenous infusion at a dose of 1 mg/kg every 2 weeks. Plasma and urine globotriaosylceramide (GL-3) levels, serum creatinine, creatinine clearance, and 24-hr urine protein levels were measured every 3 months. Kidney biopsies, ophthalmologic exams, and pure tone audiometry were performed before and 1 yr after ERT. Kidney function, including serum creatinine, creatinine clearance, and the 24-hr urine protein level, remained stable during ERT. Plasma and urine GL-3 levels were reduced within 3 to 6 months of ERT initiation. Microvascular endothelial deposits of GL-3 were decreased from renal biopsy specimens after 1 yr of treatment. The severity of sensorineural hearing loss and tinnitus did not improve after ERT. ERT is safe and effective in stabilizing renal function and clearing microvascular endothelial GL-3 from kidney biopsy specimen in Korean patients with Fabry disease.
    Journal of Korean Medical Science 05/2008; 23(2):243-50. · 1.25 Impact Factor
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    ABSTRACT: The aim of this study was to assess the relationship between prenatally diagnosed nonrefluxing hydronephrosis and urinary tract infection. We reviewed patients who were born at our institution between March 1989 and February 2006. Those who were diagnosed with fetal hydronephrosis confirmed on postnatal sonography were enrolled in the study. Hydronephrosis was graded according to the Society for Fetal Urology classification. Obstructive uropathy was diagnosed with (99m)technetium mercaptoacetyltriglycine renal scan and clinical courses. Voiding cystourethrography was done to exclude patients with vesicoureteral reflux. The prevalence of urinary tract infection was checked at 1-year followup. A total of 430 patients without reflux were enrolled in the study. Male-to-female ratio was 351:79. Urinary tract infection developed in 83 patients (19%), with first infection occurring at age 4.1 +/- 2.7 months overall and before age 6 months in 70 patients (84% of subgroup). Frequency of urinary tract infection was 1.4 +/- 0.7 (range 1 to 4) episodes during the first year. Urinary tract infection developed in 50 of 128 patients with obstructive uropathy (39%), compared to 33 of 302 patients without obstructive uropathy (11%, p <0.001). High grade hydronephrosis was associated with an increased incidence of urinary tract infection-38 of 96 patients (40%) with grade IV hydronephrosis had urinary tract infection, compared to 26 of 79 (33%) with grade III, 13 of 94 (14%) with grade II and 6 of 161 (4%) with grade I disease (p <0.001). Urinary tract infection occurred more frequently in patients with vs without hydroureter (37 of 78, or 47%, vs 46 of 352, or 13%; p <0.001). Neonates with obstructive uropathy, severe hydronephrosis or hydroureteronephrosis have increased risk of urinary tract infection even without reflux, and antibiotic prophylaxis may be recommended.
    The Journal of urology 04/2008; 179(4):1524-8. · 4.02 Impact Factor
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    ABSTRACT: Although several genetic causes of steroid-resistant nephrotic syndrome (SRNS) have been identified, occurrence of these genetic abnormalities appears to be influenced by race. Seventy Korean children (39 girls, 31 boys) with SRNS underwent analysis for mutations of WT1 and NPHS2. Although NPHS2 mutations were not present in any of the patients, two different intronic mutations of WT1, IVS9+4 C>T and IVS9+5 G>A, were detected in four patients (three girls, one boy). Among the four patients with mutation, two girls with a karyotype of 46,XY had complete XY gonadal dysgenesis, one girl with a karyotype of 46,XX had normal genitalia, and one boy with a karyotype of 46,XY had hypospadia. A kidney biopsy conducted in three of the four patients revealed focal segmental glomerulosclerosis. The incidence of WT1 mutations observed in this study was similar to that of previous reports. However, the incidence of NPHS2 mutations seems to be very rare in Korean children. Genetic diagnosis of WT1 mutations should be recommended for children with SRNS, especially in cases involving a female phenotype or males with genital anomalies.
    Pediatric Nephrology 01/2008; 23(1):63-70. · 2.94 Impact Factor
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    Journal of the Korean Society of Pediatric Nephrology 01/2007; 11(1).
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    Hye Won Park, Joo Hoon Lee, Young Seo Park
    Korean Journal of Pediatrics 01/2007; 50(12).
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    Korean Journal of Pediatrics 01/2007; 50(2).

Publication Stats

187 Citations
53.20 Total Impact Points

Institutions

  • 2006–2014
    • Asan Medical Center
      • Department of Pediatrics
      Sŏul, Seoul, South Korea
  • 2006–2013
    • Ulsan University Hospital
      Urusan, Ulsan, South Korea
  • 2005–2011
    • Seoul National University Hospital
      Sŏul, Seoul, South Korea
  • 2001–2005
    • Seoul National University
      • Department of Pediatrics
      Sŏul, Seoul, South Korea