Six proteins were thehighest occurring peptides in the PCOS group, and ten proteins were the highestoccurring peptides in the OD group (Table 3).The most significant proteins, which were expressed in the FF of at least twopatients, were the complement C3 protein, which was overexpressed in the PCOS group,and titin, serum albumin, complement C4-A, complement C4-B, alpha-1-acidglycoprotein 1 and alpha-2-macroglobulin, which were overexpressed in the ODgroup. The gene discussed is C4A; the disease is osteochondritis dissecans.