<prompt> Mixed connective tissue disease includes all the following except:PolymyositisRAOsteoarthritisSystemic sclerosis  <response>: Mixed connective tissue diseases MCTD are sometimes used to describe the disease seen in a group of patient who are identified clinically by the coexistence of features suggestive of SLE. Polymyositis, Rheumatoid arthritis and systemic sclerosis and serologically by high titres of antibodies to RNP Particle containing UI RNP. Two factors are important in lending distinctiveness to MCTD are:The paucity of renal disease. Extremely good response to corticosteroid. Some important points about connective tissue disorder: Antinuclear antibodies in autoimmune disease. Anti double stranded DNA S more specific than anti SM antibody. Anti Histone Antibodies Zrzg induced lupuserythrocytosis Anti sm antibody SLE Anti DNA topoisornerasc antibodysclerosis Antibodies of Ribonucleoprotein Antigen containing ULRNP Mixed connective tissuedisorder. Antimitochondrial antibody Primary biliarycirrhosis. 