Examples include a higher incidence of: 1) lung involvement in anti-topo-I- [37,38] and anti-Ro52/TRIM21-positive patients [39]; 2) renal crisis and poorer prognosis in anti-RNA polymerase (RNAP)I/III-positive patients [40,41]; 3) PAH in patients with anti-vascular smooth muscle cell Ab [42] or in ACA+ patients [15,37,43], and 4) digital ulceration and muscular involvement in anti-PM/Scl-75/100-positive patients [44] and in anti-U3RNP Ab-positive patients [45]. This evidence concerns the gene TRIM21 and pulmonary arterial hypertension.