The aim of this study was to define the incidence and characteristics of sclerosing encapsulating peritonitis (SEP) in pediatric peritoneal dialysis (PD) patients in Japan. A questionnaire was sent to all dialysis units with at least two pediatric PD patients. Among 687 patients registered, 11 cases (1.6%) of SEP were diagnosed. The mean age of patients with SEP at the start of PD was 9.7+/-3.6 years and at SEP diagnosis, 19.1+/-3.8 years. All patients had undergone PD for more than 5 years, and the mean PD duration was 9.6+/-3.3 years. SEP was diagnosed in 6.6% and 12% of patients dialyzed for >5 years and >8 years, respectively. The incidence of peritonitis among patients with SEP was not different from that among the Japanese pediatric registry. All patients had virtually no residual urine volume and 9 had impaired peritoneal ultrafiltration. Peritoneal calcification was the most-frequent radiological finding. Peritoneal biopsy was performed in 7 patients and confirmed sclerotic peritonitis in all. Ten patients transferred to hemodialysis, and only 1 patient underwent surgery. Three patients died. We recommend that patients on PD for more than 5 years who have impaired peritoneal ultrafiltration or peritoneal calcification should be carefully managed as presumptive cases of SEP.

To understand the genetics of steroid-sensitive nephrotic syndrome (SSNS), we conducted a genome-wide association study in 987 childhood SSNS patients and 3,206 healthy controls with Japanese ancestry. Beyond known associations in the HLA-DR/DQ region, common variants in NPHS1-KIRREL2 (rs56117924, P[4.94E-20, odds ratio (OR) [1.90)

Nephrotic syndrome is the most common cause of chronic glomerular disease in children. Most of these patients develop steroid-sensitive nephrotic syndrome (SSNS), but the loci conferring susceptibility to childhood SSNS are mainly unknown. We conducted a genome-wide association study (GWAS) in the Japanese population; 224 patients with childhood SSNS and 419 adult healthy controls were genotyped using the Affymetrix Japonica Array in the discovery stage. Imputation for six genes (, ,, , and) was conducted on the basis of Japanese-specific references. We performed genotyping for /- using a sequence-specific oligonucleotide-probing method on a Luminex platform. Whole-genome imputation was conducted using a phased reference panel of 2049 healthy Japanese individuals. Replication was performed in an independent Japanese sample set including 216 patients and 719 healthy controls. We genotyped candidate single-nucleotide polymorphisms using the DigiTag2 assay. The most significant association was detected in the region and replicated (rs4642516 [minor allele G], combined=7.84×10; odds ratio [OR], 0.33; 95% confidence interval [95% CI], 0.26 to 0.41; rs3134996 [minor allele A], combined =1.72×10; OR, 0.29; 95% CI, 0.23 to 0.37). (=1.82×10; OR, 2.62; 95% CI, 1.94 to 3.54) and (=2.09×10; OR, 0.10; 95% CI, 0.05 to 0.21) were considered primary alleles associated with childhood SSNS. (=7.01×10; OR, 3.60; 95% CI, 2.46 to 5.29) was identified as the most significant genetic susceptibility factor. The most significant association with childhood SSNS was detected in the region. Further allele/haplotype analyses should enhance our understanding of molecular mechanisms underlying SSNS.

IMPORTANCEThe development of Kawasaki disease (KD) has been suggested to be associated with droplet-or contact-transmitted infection; however, its triggers and transmission modes remain to be determined. Under an epidemic of SARS-CoV-2, the COVID-19 state of emergency in Japan served as a nationwide social experiment to investigate the impact of quarantine or isolation on the incidence of KD.OBJECTIVE To assess the role of droplet or contact transmission in the etiopathogenesis of KD. DESIGN, SETTING, AND PARTICIPANTSThis multicenter, longitudinal, cross-sectional study was conducted from 2015 to 2020 at Fukuoka Children's Hospital and 5 adjacent general hospitals. The number of admissions for KD and infectious diseases were analyzed. Participants were pediatric patients admitted to the participating hospitals for KD or infectious diseases. EXPOSURES Quarantine and isolation owing to the COVID-19 state of emergency. MAIN OUTCOMES AND MEASURES The primary end points were the ratios of patients with KD to patients with respiratory tract or gastrointestinal infections admitted from April to May in 2015 to 2019 and 2020. A Poisson regression model was used to analyze them. RESULTSThe study participants included 1649 patients with KD (median [interquartile range] age, 25 months; 901 boys [54.6%]) and 15 586 patients with infectious disease (data on age and sex were not available for these patients). The number of admissions for KD showed no significant change between April and May in 2015 to 2019 vs the same months in 2020 (mean [SD], 24.8 [5.6] vs

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