Immune infiltration levels were assessed via ssGSEA, and the key genes were validated using RT-qPCR.<h4>Results</h4>An obesity and lipid metabolism-related genes signature, consisting of five genes (IL1RN, SERPINA1, CEBPB, NFKBIA, and VNN1), was developed as a diagnostic biomarker for AMI (AUC = 0.827) and corroborated in the GSE59876 dataset (AUC = 0.870). The gene discussed is SERPINA1; the disease is obesity due to melanocortin 4 receptor deficiency.