TRIM21 and connective tissue disorder: It was found that in 20 out of 44 (45.5%) cases with overlap syndrome of NMOSD and pSS, the initial neurological event of NMOSD occurred 3.5 years before the onset of pSS (19); however, mild sicca syndrome may not sufficiently fulfill the diagnostic criteria for pSS (19–22), suggesting that anti-SSA/Ro antibodies could be an early predictor of NMOSD in the autoimmune milieu.