Homozygous protein C deficiency in two siblings.

Homozygous protein C (PC) deficiency is reported in two siblings (girl and boy) who received their proper diagnoses at the ages of 74/12 and 13/12 years respectively. The girl had perinatal asphyxia without bleeding. At 1 year of age she developed purpura fulminans. Treatment with heparin and plasma was successful. At 74/12 years she developed tender, bluish nonnecrotic skin changes after an orthopedic operation. The PC level was 0.08 U/ml. The boy had had a large intraventricular hemorrhage neonatally and developed severe brain damage. At 13/12 years he manifested the same skin changes as his sister and was treated similarly. The PC level was 0.05 U/ml. Both children now receive warfarin continuously and are essentially free of symptoms. The cases represent homozygous phenotypes in a family with a recessive trait of PC deficiency without thrombotic disease. The cases also show that severe PC deficiency may be compatible with life beyond infancy without any specific therapy.