Pathogenic variants in the COL4A3, COL4A4, and COL4A5 genes lead to collagen IV (COL4) nephropathies, including Alport syndrome (AS), thin basement membrane nephropathy, and familial forms of focal segmental glomerulosclerosis (FSGS) [1]. Here, COL4A5 is linked to focal segmental glomerulosclerosis.