Alport syndrome (AS) is a genetic disease of progressive glomerulonephritis caused by mutation in one of the type IV collagen genes (COL4A3, A4, or A5) that compose the glomerular basement membrane (GBM).1,2 Type IV collagen forms intracellular α3/α4/α5(IV) subunits to produce type IV collagen α3,4,5 (α345(IV)) trimers, which are secreted from the cells to polymerize and become part of the GBM. This evidence concerns the gene COL4A3 and Alport syndrome.