Background: Anti-Ro/SSA antibodies have been used as a diagnostic marker for Sjogren's syndrome and systemic lupus erythematosus (SLE) for decades and they are also associated with a variety of other diseases such as: dermatological and hematological disorders, interstitial pneumonitis and with hereditary C2 or C4 or C1q deficiency. The gene discussed is TRIM21; the disease is systemic lupus erythematosus.