P-selectin is used as a disease marker for cardiovascular disorder,38 rheumatoid arthritis, and arthritis39; furthermore, elevated levels of P-selectin are present in AION patients.40 The soluble form of P-selectin is the result of proteolytic cleavage of the extracellular domain after interacting with PSGL-1. The gene discussed is SELPLG; the disease is rheumatoid arthritis.