"Car. factor" deficiency revisited.

Three members of a Virginia family with a bleeding disorder were found to have a serum defect in thromboplastin generation similar to the previously reported "Car. factor" deficiency. Sera from three members of the original Car. family did not correct the defect of affected members of the Virginia family. Partial thromboplastin times of Car. deficient individuals and affected members of the Virginia family were normal. Although correction with normal serum is attained in vitro, the serum defect persisted after infusion of fresh frozen plasma. Platelet function studies of the Virginia family revealed less than 30% aggregation after the addition of exogenous ADP and disaggregation within 2 min. Evaluation of children with Noonan's syndrome, albinism, and "Portsmouth" syndrome showed coexistent platelet aggregation defects and nonspecific serum defects.