In the 1960s, Evans and colleagues described differences in response to isoniazid therapy for tuberculosis between a group of patients, this observation led to the description of NAT2 rapid and slow acetylation phenotypes6.Rapid, intermediate and slow acetylation phenotypes have been identified1,16 based on the presence of specific single nucleotide polymorphisms (SNPs) in NAT2. The gene discussed is NAT2; the disease is tuberculosis.