Homozygous protein C deficiency with delayed onset of symptoms at 7 to 10 months.

We report an inbred family with two cases of homozygous protein C deficiency and review 11 other such cases. Both patients presented in the second half of their first year of life with recurrent rapidly disappearing ecchymotic skin lesions, disseminated intravascular coagulation, and venous thrombosis. Successful treatment has been achieved by frequent infusions of plasma or prothrombin complex then maintained with Warfarin. Homozygous recessive protein C deficiency usually presents in the neonatal period with purpura fulminans. Two cases have been described elsewhere which presented in the second decade of life with milder symptoms. The present cases appear to be intermediate in time of presentation and severity of symptoms. We also review the distinction that is now evident between recessive and dominant protein C deficiency.