A Japanese Family of Hereditary Deficiency of Plasma Thromboplastin Antecedent （Factor ⅩⅠ）

A Japanese family of hereditary deficiency of plasma thromboplastin antecedent (PTA, factor XI ) was reported. The parents of the propositus were of consanguinous marriage. The levels of plasma factor Xiactivity and anitigen of the homozygotes were less than 1% of normal, and those of heterzygotes were approximately half of normal. The deficiency was transmitted as autosomal recessive trait. The homozygotes had no episodes of troublesome bleedings. The platelets of the propositus contained intrinsic factor XI-like activity as in normal, and the compensatory role of platelet factor XI-like activity for the initiation of the intrinsic pathway of coagulation was suggested.

hireditary deficiency of PTA

plltelet facter XI-like activity