The results of DeLong test showed that the AUC of NCAM/ABCA1 dual‐labeled exosomal Aβ42/40 for diagnosis of SCD was higher than that of Aβ42 (p = 0.032), T‐tau (p = 0.001), and P‐T181‐tau (p = 0.025); the AUC of NCAM/ABCA1 dual‐labeled exosomal miR‐384 for diagnosis of SCD was higher than that of Aβ42 (p = 0.027), Aβ42/40 (p = 0.001), T‐tau (p = 0.001), P‐T181‐tau (p = 0.008), and NfL (p = 0.000). The gene discussed is ABCA1; the disease is Schnyder corneal dystrophy.