Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to Stevens-Johnson syndrome/toxic epidermal necrolysis ?
    ### Response:
    Several genetic changes have been found to increase the risk of SJS/TEN in response to triggering factors such as medications. Most of these changes occur in genes that are involved in the normal function of the immune system.  The genetic variations most strongly associated with SJS/TEN occur in the HLA-B gene.
    