Hereditary deficiency of C5 in association with discoid lupus erythematosus.

A 29-year-old woman with discoid lupus erythematosus had undetectable classic pathway complement activity.
Hypocomplementemia was due to selective deficiency of C5. One of her children was also deficient.
To our knowledge this is the first documented case of an association between discoid lupus erythematosus and C5 deficiency.. 
