A diagnosis of SS is based on the weighted sum of 5 items, which include: (1) labial salivary glands with focal lymphocytic sialadenitis (weight 3 points); (2) identification of anti-nuclear antibodies against ribonucleoproteins Ro/SSA (weight 3 points); (3) ocular staining score ≥ 5 in at least 1 eye (weight 1 point); (4) Schirmer’s test ≤ 5 mm/5 min in at least 1 eye (weight 1 point); (5) unstimulated saliva flow rate ≤ 0.1 ml/min (weight 1 point). The gene discussed is TRIM21; the disease is synovial sarcoma.