This gene encodes a haptoglobin preproprotein, which is processed into alpha and beta chains that form a tetramer. Haptoglobin's primary function is to bind free plasma hemoglobin, facilitating its degradation while preventing iron loss and kidney damage. Mutations in this gene or its regulatory regions can cause ahaptoglobinemia or hypohaptoglobinemia and have been associated with diabetic nephropathy, coronary artery disease, Crohn's disease, and susceptibility to Parkinson's disease. The protein also exhibits antimicrobial properties.