Stapleton and others found candidate variants in 10 families and identified a likely pathogenic variant in COL4A5 in one family and a variant of unknown significance (VUS) in COL4A3 in another (Stapleton et al., 2020), which confirmed the heterogeneity of IgA nephropathy (Stapleton et al., 2020) and provided evidence that while a proportion of patients with renal IgA deposits may carry pathogenic variants of known kidney disease-related genes such as the Col4 gene, others may not (Stapleton et al., 2020). This evidence concerns the gene COL4A5 and IgA glomerulonephritis.