Genetic predispositions, such as HLA-B15:02 (associated with carbamazepine-induced TEN, particularly in Southeast Asian populations), HLA-A31:01 (carbamazepine hypersensitivity in European, Japanese, and Latin American populations), and HLA-B*58:01 (allopurinol-induced TEN in Asian populations), are important risk factors that guide genetic screening recommendations before prescribing certain high-risk drugs. Here, HLA-B is linked to toxic epidermal necrolysis.