Recent genetic studies have identified the close genetic susceptibility of ATD‐induced agranulocytosis, namely, thionamide‐induced agranulocytosis (TIA), in various ethnic groups, especially those genes that encode the major HLAs with alleles HLA‐B*38:02, HLA‐B*27:05, and HLA‐DRB1*08:03.4, 5, 6, 7, 8. Here, HLA-DRB1 is linked to transient ischemic attack.