In particular, hypocomplementemia and antibodies directed against nuclear components; including anti-nuclear antibodies (ANA); extractable nuclear antigens (ENA) inclusive of anti-Ro, anti-La, anti-Sm and anti-RNP; and anti-double stranded DNA (dsDNA) antibodies should prompt the clinician to consider a diagnosis of a connective tissue disease or lupus. This evidence concerns the gene BTG3 and systemic lupus erythematosus.