In drug-triggered eruptions involving HLA polymorphisms, ERAP1 mutations are correlated with AHS in HLA-B*57:01 carriers, and ERAP2 mutations have been associated with nevirapine-induced SJS/TEN in HLA-C*04:01 carriers (26, 54). This evidence concerns the gene ERAP1 and mitochondrial DNA depletion syndrome 4a.