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Abstract The genotype–phenotype correlation of the X-linked Alport syndrome (XLAS) has been well elucidated in males, whereas it remains unclear in females. In this multicenter retrospective study, we analyzed the genotype–phenotype correlation in 216 Korean patients (male:female = 130:86) with XLAS between 2000 and 2021. The patients were divided into three groups according to their genotypes: the non-truncating group, the abnormal splicing group, and the truncating group. In male patients, approximately 60% developed kidney failure at the median age of 25.0 years, and kidney survival showed significant differences between the non-truncating and truncating groups (P

Background The clinical features of pediatric rhabdomyolysis differ from those of the adults with rhabdomyolysis; however, multicenter studies are lacking. This study aimed to investigate the characteristics of pediatric rhabdomyolysis and reveal the risk factors for acute kidney injury (AKI) in such cases. Methods This retrospective study analyzed the medical records of children and adolescents diagnosed with rhabdomyolysis at 23 hospitals in South Korea between January 2007 and December 2016. Results Among 880 patients, those aged 3 to 5 years old composed the largest subgroup (19.4%), and all age subgroups were predominantly male. The incidence of AKI was 11.3%. Neurological disorders (53.6%) and infection (39.0%) were the most common underlying disorder and cause of rhabdomyolysis, respectively. The median age at diagnosis in the AKI subgroup was older than that in the non-AKI subgroup (12.2 years vs. 8.0 years). There were no significant differences in body mass index, myalgia, dark-colored urine, or the number of causal factors between the two AKI-status subgroups. The multivariate logistic regression model indicated that the following factors were independently associated with AKI: multiorgan failure, presence of an underlying disorder, strong positive urine occult blood, increased aspartate aminotransferase and uric acid levels, and reduced calcium levels. Conclusions Our study revealed characteristic clinical and laboratory features of rhabdomyolysis in a Korean pediatric population and highlighted the risk factors for AKI in these cases. Our findings will contribute to a greater understanding of pediatric rhabdomyolysis and may enable early intervention against rhabdomyolysis-induced AKI.

Purpose To investigate differences in clinical features, blood/urinary findings, and prognosis in different age groups of patients with Henoch-Schönlein purpura (HSP). Methods A total of 469 patients with HSP were analyzed retrospectively from June 2003 to February 2016. We classified patients into child or adult groups based on their age. Results The adult group had more patients with anemia (child vs. adult; 7.5% vs. 16.4%), and higher immunoglobulin A (IgA) (30.0% vs. 50.0%) levels, C-reactive protein (34.2% vs. 54.0%) and uric acid (3.1% vs. 12.1%) levels than the child group. The child group was highly positive for Mycoplasma pneumoniae immunoglobulin M (IgM) (34.4%). More patients in the child group presented with high levels of antistreptolysin O (24.7% vs. 2.9%) and high C4 (11.5% vs. 4.2%). Low C3 (1.1% vs. 10.2%) levels, and renal involvement with gross hematuria (8.6% vs. 21.5 %), nonnephrotic proteinuria (1.1% vs. 11.2%), and nephrotic syndrome (1.1% vs. 6.0%) were common in the adult group. Adults also had poorer renal outcomes [persistent hematuria/proteinuria (10.5% vs. 32.8%), and chronic kidney disease (0% vs. 11.2%)] than the child group. Risk factors for renal involvement such as older age and higher level of uric acid were only found in the child group. The risk factors for poor renal outcome were nephrotic syndrome in the child group and gross hematuria in the adult group. Conclusion In this study, child and adult groups presented with different clinical manifestations of HSP. We found that risk factors for renal involvement included age and high uric acid level in the child group. Moreover, nephrotic syndrome in the child group and gross hematuria in the adult group increased the risk of poor renal outcome.

Nephrogenic diabetes insipidus (NDI) can cause nonobstructive hydronephrosis. Congenital NDI (CNDI) is caused by a genetic mutation. This case report presents a 12-year-old girl who was incidentally diagnosed with nonobstructive hydronephrosis due to NDI caused by AQP2 gene mutation after being evaluated for microscopic hematuria found on routine health examination at school. The patient’s medical and family history was unremarkable, and she complained of nocturia only at the time of the clinic visit. Bilateral hydronephrosis on abdominal ultrasonography prompted a water deprivation test, leading to diagnosis of NDI. Genetic study confirmed p.Asn (AAC)123Ser (AGC) in exon 2 of the AQP2 gene. Polyuria and hydronephrosis improved following arginine-vasopressin therapy. CNDI responsive to treatment should be considered as a possible cause of nonobstructive hydroureter.

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. [ABSTRACT FROM AUTHOR]