A 27-year-old male was investigated in the St. Marianna Hospital because of recurrent thrombosis which first appeared at his 25 years of age. Since he had the first episode of thrombosis as myocardial infarction, he had an attack of femoral vein thrombosis and subsequently he had a surgery of colon resection due to the superior mesenteric venous thrombosis.
The plasminogen activity assay by an amidolytic method revealed 40%, 47.8%, 57.2%, and 108% of normal in the propositus, his brother, father and mother, respectively. The antigen level of plasminogen was within normal range in both propositus and his family.
No discrete difference was noted between the abnormal and normal plasminogens by SDS PAGE under non-reducing and reducing conditions. SDS PAGE in reduced system for cleavage of plasminogen by urokinase, while the H chain and the L chain of plasminogen appeared more slowly in present abnormal plasminogen in the cleavage of plasminogen by streptokinase.
By the procedure of preparative isoelectric focusing method, present abnormal plasminogen demonstrated additional bands for each of corresponding bands equivalent to those of normal plasminogen.
The reason why only the propositus developed recurrent thrombosis, while no other members did not, is not easily explained, although obesity which had progressively appeared during 6 months prior to the attack might have contributed to thrombosis as a causative risk factor.