Prekallikrein Deficiency in a Kindred with Kininogen Deficiency and Fitzgerald Trait Clotting Defect EVIDENCE THAT HIGH MOLECULAR WEIGHT KININOGEN AND PREKALLIKREIN EXIST AS A COMPLEX IN NORMAL HUMAN PLASMA

hereditary deficiency of kininogens is deficient in kininogen antigens; heterozygous relatives are par-tially deficient in plasma kininogen antigens. In addi-tion, plasma from the proband is partially deficient in functional and antigenic properties of a plasma pre-kallikrein, and the relatives heterozygous for kinino-gen deficiency are also partially deficient in the plasma prekallikrein. It is possible that the defects are both inherited and that the inheritance of a deficiency of prekallikrein is genetically linked to the inheritance of a deficiency of kininogen. Alternatively, it is possible that the deficiency of prekallikrein may be due to its hypercatabolism which could be a conse-quence of a deficiency of high molecular weight kininogen that may stabilize the prekallikrein in plasma. Evidence to support this possibility is pre-sented by the fact that prekallikrein and high molecular weight kininogen apparently exist as a complex in normal plasma, because monospecific antiserum to kininogen removed both high molecular weight kininogen and prekallikrein from plasma, and vice versa. Moreover, prekallikrein was not adsorbed from kininogen-deficient plasma by antiserum to kininogen unless high molecular weight kininogen was first added to the plasma. Low molecular weight kininogen did not participate in these reactions. Received for publication 24 September 1976 and in re-vised form 25 April 1977