Other examples include the findings of podocyte-related gene mutations in some patients with histological membranoproliferative glomerulonephritis [10], mutations in a ciliary gene (TTC21B) causing focal segmental glomerulosclerosis [15] and mutations in a recently described gene (DGKE) resulting in atypical haemolytic uraemic syndrome [16], membranoproliferative glomerulonephritis [17] and steroid-resistant nephrotic syndrome [10]. Here, TTC21B is linked to membranoproliferative glomerulonephritis.