The haptoglobin (HP) gene deletion allele (HP(del)) is responsible for anhaptoglobinemia and a genetic risk factor for anaphylaxis reaction after transfusion due to production of the anti-HP antibody.
Being homozygous for the Hp gene deletion (HP(del)) is the only known cause of congenital anhaptoglobinemia, and clinical diagnosis of HP(del) before transfusion is important to prevent anaphylactic shock.
To date, there have been no population studies of plasma levels of Hpr, particularly in relation to hemolysis and a high prevalence of ahaptoglobinemia as found in malaria endemic areas.