**12. Future directions using pharmacogenetic tools to identify genetic predisposition to SCARs**

The occurrence of SCAR is unpredictable but this uncertainty can be minimized to some extent by performing a pharmacogenetic assessment. If done before initiating patients on potential drugs, the occurrence of SCAR can be prevented as well. Human Leukocyte Antigens (HLA) genes have been evaluated in detail that has been found to have an association with SCAR variations observed in some patients on specific drugs (listed in **Table 6**). Having knowledge about genetic predisposition will help to detect patients at higher risk of developing SCAR. A study by Esmaeilzadeh H. *et al* study from Iran has shown Steven Johnson Syndrome (SJS)/Toxic Epidermal Necrolysis (TEN) as the most common drug-induced SCAR presentation and the most common culprit drug as beta-lactam antibiotics followed by carbamazepine. The presence of HLA-A\*02:01 and A\*51:01 was also shown to increase the risk of SCAR while A\*11:01 had a protective role against SCAR. Those with HLA-A\*02:01, HLA-A\*24:02, and HLA-B\*51:01 were an increased SJS as observed in the same study [55].


*Abbreviations: AIDS- Acquired immune deficiency syndrome, LGV- Lymphogranuloma venereum, NRTI- Nucleoside reverse transcriptase inhibitors, NNRTIs- Non-nucleoside reverse transcriptase inhibitors, NSAIDs- Non-steroidal antiinflammatory drugs, TNF alpha- Tumor Necrosis Factor-alpha, HLA- Human leukocyte antigens.*

#### **Table 6.**

*Predisposing factors for Steven Johnson syndrome/toxic epidermal necrolysis.*
