The therapeutic approach to childhood nephrotic syndrome is based on a series of studies that began with an international collaborative effort sponsored by the International Study of Kidney Disease in Children in 1967. The characteristics of children presenting with nephrotic syndrome have changed over recent decades with greater frequency of the challenging condition focal segmental glomerulosclerosis and a greater prevalence of obesity and diabetes mellitus, which may be resistant to glucocorticoids in the former and exacerbated by long-term glucocorticoid therapy in the latter 2 conditions. The Children's Nephrotic Syndrome Consensus Conference was formed to systematically review the published literature and generate a children's primary nephrotic syndrome guideline for use in educational, therapeutic, and research venues.

Steroid-sensitive nephrotic syndrome (SSNS) accounts for .80% of cases of nephrotic syndrome in childhood. However, the etiology and pathogenesis of SSNS remain obscure. Hypothesizing that coding variation may underlie SSNS risk, we conducted an exome array association study of SSNS. We enrolled a discovery set of 363 persons (214 South Asian children with SSNS and 149 controls) and genotyped them using the Illumina HumanExome Beadchip. Four common single nucleotide polymorphisms (SNPs) in HLA-DQA1 and HLA-DQB1 (rs1129740, rs9273349, rs1071630, and rs1140343) were significantly associated with SSNS at or near the Bonferroni-adjusted P value for the number of single variants that were tested (odds ratio, 2.11; 95% confidence interval, 1.56 to 2.86; P=1.68310 26 (Fisher exact test). Two of these SNPs-the missense variants C34Y (rs1129740) and F41S (rs1071630) in HLA-DQA1-were replicated in an independent cohort of children of white European ancestry with SSNS (100 cases and #589 controls; P=1.42310 217). In the rare variant gene set-based analysis, the best signal was found in PLCG2 (P=7.825310 25). In conclusion, this exome array study identified HLA-DQA1 and PLCG2 missense coding variants as candidate loci for SSNS. The finding of a MHC class II locus underlying SSNS risk suggests a major role for immune response in the pathogenesis of SSNS.

Proteinuria in children with sickle cell anemia (SCA) is an early sign of sickle nephropathy, and portends the development of nephrotic syndrome and chronic renal failure. Enalapril has been shown to reduce proteinuria in adult patients with SCA, but the potential benefits of hydroxyurea in this clinical setting have not been reported. A single institution retrospective analysis was performed. Children with sickle nephropathy were identified, and the laboratory effects of enalapril and hydroxyurea therapy were evaluated in children with substantial proteinuria. Three children developed proteinuria at 8 +/- 1 years of age. Pre-treatment laboratory studies included a low serum albumin (2.8 +/- 0.8 g/dl) and a highly elevated urine protein/creatinine ratio (6.9 +/- 3.7, normal <0.2). Enalapril treatment for 3.0 +/- 1.3 years normalized serum albumin (3.9 +/- 0.3 g/dl) without significant changes in serum potassium, serum creatinine, or systolic blood pressure. However, urine protein/creatinine remained elevated in the nephrotic range (1.6 +/- 0.7). The addition of hydroxyurea therapy for 3.5 +/- 1.2 years increased fetal hemoglobin levels (7.0 +/- 3.6% to 21.0 +/- 3.2%) and was associated with a near-normal urine protein/creatinine ratio (0.5 +/- 0.1). Enalapril therapy for children with sickle nephropathy reduces urinary protein excretion and normalizes serum albumin. Hydroxyurea therapy may further normalize the urine protein/creatinine ratio. Combination therapy should be tested prospectively in children with sickle nephropathy.