Atypical hemolytic uremic syndrome: Korean pediatric series.

Background Atypical hemolytic uremic syndrome ( aHUS) is a rare disease with a genetic predisposition. Few studies have evaluated the disease in the Asian population. We studied a Korean pediatric cohort to delineate the clinical characteristics and genotypes. Methods A multicenter cohort of 51 Korean children with aHUS was screened for mutations using targeted exome sequencing covering 46 complement related genes. Anti-complement-factor- H autoantibody (anti- CFH) titers were measured. Multiplex ligation-dependent probe amplification assay was performed to detect deletions in the complement factor- H related protein genes ( CFHR) in the patients as well as in 100 healthy Korean controls. We grouped the patients according to etiology and compared the clinical features using Mann-Whitney U-test and chi-squared test. Results Fifteen patients (group A, 29.7%) had anti- CFH, and mutations were detected in 11 (group B, 21.6%), including one with combined mutations. The remaining 25 (group C, 49.0%) were negative for both. The prevalence of anti- CFH was higher than the worldwide level. Group A had a higher onset age than group B, although the difference was not significant. Group B had the worst renal outcome. Gene frequencies of homozygous CFHR1 deletion were 73.3%, 2.7% and 1% in group A, group B + C and the control, respectively. Conclusions The incidence of anti- CFH in the present Korean aHUS cohort was high. Clinical outcomes largely conformed to the previous reports. Although the sample size was limited, this cohort provides a reassessment of clinicogenetic features of aHUS in Korean children. [ABSTRACT FROM AUTHOR]