In summary, HLA-B*44:03 seems to be a cross-ethnic susceptible gene with a strong association in Japanese, Brazilian, Indian, and Thai, whereas HLA-A*02:06, HLA-B*44:03, toll-like receptor 3 (TLR3), prostaglandin-E receptor 3 (PTGER3), and IKZF1, by using GWAS approach, were identified as primary association to cold medicine-induced SJS/TEN with severe ocular involvement in Japanese (55, 60, 61, 78) (Table 1). The gene discussed is PTGER3; the disease is toxic epidermal necrolysis.