PROTEIN-S TOKUSHIMA - AN ABNORMAL PROTEIN-S FOUND IN A JAPANESE FAMILY WITH THROMBOSIS

An abnormal protein S (PS) was found in a Japanese family with a high incidence of thrombosis. The proband is a woman who was born in Tokush ima Prefecture. She had superior sagittal sinus thrombosis, thrombophl ebitis of the left leg, and thrombosis of the placenta. She had a norm al plasma level of free PS antigen but decreased PS activity. Her moth er and aunt also had thrombophlebitis of the leg, and together with fo ur other family members also showed a normal level but decreased activ ity of PS. This suggests that hereditary dysfunction of PS is inherite d in this family as an autosomal dominant trait. The proband's PS appe ars to have a slightly higher molecular weight than normal PS both in the intact and modified form, suggesting that it has a molecular defec t on the carboxyl-terminal side of the thrombin-sensitive site. This a bnormal PS with apparently unique characteristics was named PS Tokushi ma.