Increasingly, pathogenic variants in COL4A3–COL4A5 are found in individuals with proteinuria (‘nephrotic syndrome’, ‘nephrotic range proteinuria’, ‘steroid-resistant nephrotic syndrome’) or with the renal biopsy finding of focal and segmental glomerulosclerosis (FSGS)[11, 12]. The gene discussed is COL4A3; the disease is focal segmental glomerulosclerosis.