HLA-B and toxic epidermal necrolysis: As dermatological reactions comprised the largest category of ADRs received by HSA and local data were deemed necessary to assess the applicability of the HLA-B*1502 association to CBZ-induced SJS/TEN in Singapore, HSA embarked on a program in 2009 to develop infrastructure for collection, storage, and analysis of DNA samples from patients who had experienced serious skin rash, and to capture phenotypic data associated with those samples.