In this study, we therefore characterised HLA class I genes (HLA-A [Gene ID: 3105], HLA-B [Gene ID: 3106], and HLA-C [Gene ID: 3107]) in 33 SJS/TEN patients of diverse ethnic backgrounds residing in the UK presenting at three of the largest dedicated eye centres in the UK, to determine whether any associations exist between these patients’ genotype, phenotype and precipitant for our patients compared with published data from patients in Far East Asia. This evidence concerns the gene HLA-C and toxic epidermal necrolysis.