Vitamin K-dependent protein S

Thrombophilia due to protein S deficiency, autosomal dominant

A hemostatic disorder characterized by impaired regulation of blood coagulation and a tendency to recurrent venous thrombosis. Based on the plasma levels of total and free PROS1 as well as the serine protease-activated protein C cofactor activity, three types of THPH5 have been described: type I, characterized by reduced total and free PROS1 levels together with reduced anticoagulant activity; type III, in which only free PROS1 antigen and PROS1 activity levels are reduced; and the rare type II which is characterized by normal concentrations of both total and free PROS1 antigen, but low cofactor activity.

Thrombophilia due to protein S deficiency, autosomal recessive

A very rare and severe hematologic disorder resulting in thrombosis and secondary hemorrhage usually beginning in early infancy. Some affected individuals develop neonatal purpura fulminans, multifocal thrombosis, or intracranial hemorrhage.