Lupus erythematosus-like syndrome with a familial deficiency of C2.

Several cases of isolated C2 deficiency in man have been reported in the medical literature. The earliest cases did not seem to be associated with known diseases or syndromes; more recently, reports of C2 deficiency associated with systemic lupus erythematosus; anaphylactoid purpura, recurrent infections, and dermatomyositis have appeared. We report here another case of C2 deficiency. The propositus, a 24-year-old woman, had a lupus erythematosus-like rash and a history of arthralgia, as well as a selective deficiency of C2. Studies of hemolytic C2 of the immediate members of her family indicate an autosomal-recessive mode of inheritance. These findings add to the increasing evidence that a C2 deficiency predisposes some persons to serious vascular diseases.