To our knowledge, only one study has addressed circulating syndecan-1 levels in RA so far: in a small cohort (18 patients) of relatively young patients (mean age 38,1 ±7.8), syndecan-1 levels were lower than in our study (median 12.8 (8.7–21.5) ng/ml) [36]. The gene discussed is SDC1; the disease is rheumatoid arthritis.