Moreover, MCTD exhibited greater alterations in surrogate markers of CVD than other connective tissue disorders, such as pSS or SSc (41) and different mechanisms of vascular damage between MCTD and SSc have been reported (42), which is in accordance with the differences in the association between IgG anti-HDL-PON1 axis and disease-related autoantibodies herein reported. This evidence concerns the gene PON1 and mixed connective tissue disease.