HCP5 and toxic epidermal necrolysis: Another GWAS conducted on Japanese patients showed that a total of 21 SNPs located on 6p21 were significantly associated with allopurinol-induced SJS/TEN after analyzing a total of 890,321 SNPs, and the strongest associations were found for the BAT1 (rs2734583) and HCP5 (rs3094011) genes (OR 66.8; 95% CI 19.8–225.0; P = 2.44 × 10− 8).