PGRMC1 and chronic kidney disease: Various collagens, blood proteins (e.g., α1-antitrypsin, serum albumin, haemoglobin α chain, and fibrinogen α chain), kidney-specific proteins (e.g., uromodulin, sodium/potassium-transporting ATPase γ chain, and membrane-associated progesterone receptor component 1) and fragments of different secreted proteins have been identified as markers for the diagnosis of CKD.