This study identified 25 immune-related DEGs, some of which were known to be associated with obesity, such as ELANE, SAA1, LCN2, OLFM4, CCL2, OAS3, BPI, AGR2, IL-17 A, DEFA1, DEFA3, MMP8, CTSG, DUOX1, and CXCL10, while BPIFA1, CRISP3, CEACAM8, IFIT1, RASD2, PRTN3, F2RL2, PDE1C, DEFA4, and FCN2 have not been reported to be related to obesity. The gene discussed is DEFA3; the disease is obesity due to melanocortin 4 receptor deficiency.