Pharmacogenetics of toxic epidermal necrolysis

Importance of the field: Toxic epidermal necrolysis (TEN) and StevensJohnson Syndrome (SJS) are two of the most severe drug-induced cutaneous reactions. Advances in genome technologies have allowed researchers to identify genetic markers associated with this drug-associated event and these have provided a potential tool for prevention. Areas covered in this review: Current updates of genetic biomarkers that have been identified as being associated with TEN/SJS induced by several drugs, and the associations of these markers in different populations, are discussed. What the reader will gain: The strong association of HLA-B*1502 and carbamazepine (CBZ)-induced TEN/SJS have been reported by several independent studies. This association was mostly observed in patients of Southeast Asian ancestry; it was not observed in populations with low HLA-B*1502 allele frequency. Studies also suggest that drugs with a similar chemical structure to CBZ might also induce TEN/SJS in patients with HLA-B*1502. In addition to CBZ, HLA-B*5801 was also found to associate with allopurinol-induced TEN/SJS. This strongly suggests that the associations of these markers with TEN/SJS are drug specific. Take home message: The strong association between CBZ and HLA-B*1502 has prompted the US Food and Drug Administration to update the label for CBZ to include genetic information and to recommend genetic testing before prescribing CBZ. Patients with Asian ancestry or who are from regions prevalent in HLA-B*1502 should be screened before CBZ treatment.