SAMD1 and autoimmune polyendocrinopathy: We further detected the expression of SAMD1 in HUVECs of the control group (without any treatment), health group (cultured with 10% healthy serum), and APS group (cultured with 10% APS patient serum), and the qRT‐PCR and western blot found that the expression of SAMD1 in the APS group was lower than that in the health group and control group (Figure 1D,E, p < .05), but no obvious difference was seen between the health group and the control group.