The receiver operating characteristic curve analysis indicated that the cutoff for serum Gd-IgA1 levels for differentiating IgAN from non-IgA glomerular diseases was 3236 ng/ml with a sensitivity of 92% and a specificity of 81.8% in children < 12 years and 5284 ng/ml with a sensitivity of 73.3% and a specificity of 90.9% in children ≥ 12 years, respectively. This evidence concerns the gene IGHA1 and glomerular disorder.