Severe Protein S Deficiency in a Newborn

Protein S is a vitamin K-dependent glycoprotein which acts as a cofactor for the anticoagulant activity of protein C.1,2 With production under autosomal control, heterozygotes produce half-normal levels and thrombotic disease may develop.3-6 Although thromboses occur primarily in adults, there are isolated reports of their occurrence in affected children.7-13 Severe protein C deficiency results in a syndrome in which affected children develop multiple thromboses in the newborn period.14 A recent report described a child with homozygous protein S deficiency who presented with neonatal purpura fulminans and other thromboses similar to those found in protein C deficiency.15,16 In this report, we