Our research has some limitations: he lack of data regarding the measurement of oxidative stress markers in our SS patients is related to insufficient available material; the impossibility of performing a correlation analysis between the mtDNA copies and the expression levels of MNF1, MFF, and TFAM genes, because we have collected a second round of blood draw in the subgroup of 27 SS patients at a later time, specifically used for the RNA experiments; hte absence of functional studies to understand the molecular mechanisms underlying our results. This evidence concerns the gene UQCC2 and synovial sarcoma.