If a patient who has tolerated allopurinol for a prolonged period of time is subsequently found to be positive for the HLA-B*58:01 gene, how would you manage urate-lowering therapy thereafter?  

There is a strong association between the presence of the HLA-B*58:01 allele and allopurinol-related severe cutaneous adverse reactions (SCAR* - Stevens-Johnson Syndrome, Toxic Epidermal Necrolysis or Severe Hypersensitivity Syndrome). This association was demonstrated in a Taiwanese study by Hung e...