Post-streptococcal acute glomerulonephritis (PSAGN) is one of the most important and intriguing conditions in the discipline of pediatric nephrology. Although the eventual outcome is excellent in most cases, PSAGN remains an important cause of acute renal failure and hospitalization for children in both developed and underdeveloped areas. The purpose of this review is to describe both the typical and less common clinical features of PSAGN, to outline the changes in the epidemiology of PSAGN over the past 50 years, and to explore studies on the pathogenesis of the condition with an emphasis on the search for the elusive nephritogenic antigen.

Serum galactose-deficient IgA1 (Gd-IgA1) is an inherited risk factor for adult IgA nephropathy (IgAN). The goal of this study is to determine the heritability of serum Gd-IgA1 levels in children with IgAN and Henoch-Schönlein nephritis (HSPN). For this purpose, we obtained serum from 34 Caucasian families (20 pediatric cases of HSPN, 14 pediatric cases of IgAN, and 54 of their first-degree relatives), as well as from 51 age- and ethnicity-matched pediatric controls and 141 healthy adult controls. Serum Gd-IgA1 levels were quantified using an HAA-lectin-based ELISA. Children with either IgAN or HSPN had significantly higher Gd-IgA1 levels compared with pediatric controls (p = 1.7 × 10−7 and p = 6.5 × 10−9, respectively). Serum levels of Gd-IgA1 were also elevated in a large fraction of the first-degree relatives of pediatric IgAN and HSPN patients compared with unrelated adult controls (p = 3.2 × 10−6 and p = 5.1 × 10−4, respectively). The unilineal transmission of the trait was observed for 75% of families, bilineal transmission in 5%, and sporadic occurrence in 20%. The age-, gender-, and household-adjusted heritability of serum Gd-IgA1 level was estimated at 76% (p = 0.021) in pediatric IgAN patients and at 64% (p = 0.018) in HSPN patients. Our data demonstrate that serum Gd-IgA1 levels are highly inherited in pediatric IgAN and HSPN, providing support for yet another shared pathogenic link between these disorders.