Suzuki et al. reported that serum levels of IgA, Gd-IgA1, Gd-IgA1-specific IgG (the best selected parameter with a sensitivity of 89% and specificity of 92%), and Gd-IgA1-specific IgA were elevated in patients with IgAN, compared to both the group of healthy patients and patients with other renal diseases [92]. This evidence concerns the gene IGHA1 and kidney disorder.