Protein C deficiency and anticardiolipin antibodies in a family with premature stroke

Anticardiolipin antibodies and, rarely, protein C deficiency have been described in patients with stroke. The familial coexistence of these two prothrombotic defects has not been previously reported. We describe a family with debilitating strokes occurring at an early age in whom both anticardiolipin antibodies and protein C deficiency were found. The propositus and her deceased mother both suffered a stroke at age 50 years. The propositus had both anticardiolipin antibodies and protein C deficiency. After a detailed study of the remainder of the family, the tendency to form anticardiolipin antibodies appeared to be inherited independently of the protein C deficiency. The simultaneous occurrence of these abnormalities in one family suggests that it may be useful to test for both anticardiolipin antibodies and inherited anticoagulant protein deficiencies in patients with unusual or unexplained stroke. The differential expression of both protein C deficiency and anticardiolipin antibody production in various members of the described family may allow insight into the relative contributions of these two prothrombotic abnormalities for the development of thrombotic complications, including stroke.