<prompt> Anti-topoisomerase I is marker of:Systemic sclerosisClassic polyaeritis nodosaNephrotic syndromeRheumatoid ahritis  <response>: Two ANAs strongly associated with systemic sclerosis are as follows:- One of these,directed against DNA topoisomerase I anti-Scl 70, is highly specific. Patients who have this antibody are more likely to have pulmonary fibrosis and peripheral vascular disease. The other, an anti-centromere antibody, is found in 20 to 30 of patients, who tend to have the CREST syndrome. 