<prompt> DNA topoisomerase 1 autoantibody is specific for?Limited cutaneous systemic sclerosisMixed connective tissue diseaseDiffuse sclerodermaSLE  <response>: Scl-70 antibodies are associated with more severe scleroderma disease. Anti-topoisomerase antibodies can be classified according to their immunoglobulin class IgM, IgG or IgA. IgG-ATA is found most frequently in scleroderma, with IgA being quite common but IgM very infrequent. Ref Robbins 9e pg 230 