Receiver operating characteristic analysis indicated an AUC value of 0.65 ± 0.063 (95% CI 0.52–0.77, P = 0.03) for plasma CXCL12 when comparing ALS and HC cases, with the optimal cut-off at 1910 pg/mL determined by the Youden index (0.26; sensitivity of 57.5%; specificity of 68.6%; Fig. 2C). The gene discussed is CXCL12; the disease is amyotrophic lateral sclerosis.