Validation was performed using qPCR and ELISA in CS patient serum and 5-Aminosalicylic Acid (5-ASA) treatment in HUT78 T cells.<h4>Results</h4>A total of 118 genes exhibited suggestive or potential causal associations with CS, primarily enriched in CD4<sup>+</sup> and CD8<sup>+</sup> T cells. Here, CD8A is linked to Cowden syndrome 1.