December 1990

Picture of the Month

Author Affiliations

Contributed from the Department of Hematology, Walter Reed Army Institute of Research, Washington, DC.

Am J Dis Child. 1990;144(12):1353-1354. doi:10.1001/archpedi.1990.02150360079026

Denouement and Discussion 

Protein C Deficiency 

Manifestations  Protein C, produced by the liver, is essential in the regulation of coagulation and is a vitamin K—dependent proenzyme. A proenzyme is an inactive precursor that is converted to an active enzyme by the action of acid, another enzyme, or by other means. Protein C rapidly inactivates the active forms of V and VIII, resulting in an inhibited coagulation process. In the absence of protein C, thromboses (venous and microvascular) and skin necrosis take place. Skin necrosis usually occurs during the first 2 to 12 hours after birth, and consists of ecchymotic areas that progress to indurated purple-black lesions with central bullae and peripheral erythema. They occur most commonly in the scalp (associated with vertex presentation deliveries), buttocks, and areas in which there is soft-tissue trauma due to pressure. The lesions are similar to the skin lesions present in warfarininduced necrosis of the

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