Protein C deficiency and stroke in early life

Plasma concentrations of protein C, protein S and antithrombin III were measured in 33 unselected children with a history of cryptogenic stroke (group 1), four children with previously ascertained low plasma concentrations of protein C following stroke (group 2) and 42 healthy children undergoing minor surgery (group 3). Protein S and antithrombin III were normal in all patients. Low concentrations of protein C were found in two patients in group 1 and in six healthy children in group 3. Low protein C concentrations returned to normal over many months in three of the four patients in group 2. Prophylactic antithrombotic therapy and/or termination of pregnancy had been carried out unneccessarily in two families in whom inherited protein C deficiency was not confirmed. The suggestion that heterozygous protein C deficiency contributes to the risk of arterial stroke was not supported by this study.