After propensity score matching and adjusting for OAC use, no MHC group was associated with increased IS risk (adjusted SHRs (95% CI): depression 0.961 (0.857–1.077), bipolar disorder 1.398 (0.947–2.006), anxiety disorder 0.878 (0.718–1.034), schizophrenia 0.803 (0.594–1.085) and any MHC 1.033 (0.985–1.085)). The gene discussed is HLA-C; the disease is schizophrenia.