SDC2 and polycystic ovary syndrome: As shown in a Venn diagram (Fig. 4C), examination of these two gene sets helped us identify four characteristic PCOS-related biomarkers, namely A-kinase anchoring protein 5 (AKAP5), apolipoprotein H (APOH), HD domain containing 3 (HDDC3), and syndecan 2 (SDC2).