Severe congenital protein C deficiency: Description of a new mutation and prophylactic protein C therapy and in vivo pharmacokinetics

Severe congenital protein C deficiency is a rare lifethreatening disorder that presents with purpura fulminans, disseminated intravascular coagulation, and thrombotic complications during the neonatal period. Affected children require acute replacement therapy with fresh frozen plasma or protein C concentrate, for example, Ceprotin (Baxter AG, Vienna). Long-term management and outcome is dependent on effective anticoagulation with warfarin, low-molecular weight heparin, or protein C concentrate. We describe the successful use of intravenous protein C concentrate for thrombotic prophylaxis in 2 sisters with severe type I protein C deficiency. Individualized long-term prophylactic regimens were developed based on clinical response. In vivo pharmacokinetic analyses of protein C concentrate were performed in each patient. Analysis of the protein C gene coding sequences identified 2 mutations in both patients, the previously described Arg ₁₆₉ to Trp mutation, and a novel mutation that changes Cys ₁₇ into a stop codon.