Haplotype-specific PCR for diplotyping.

N-acetyltransferase 2 (NAT2) is an enzyme that acetylates many kinds of drugs, including the antituberculosis drug isoniazid. The gene is highly diverse across populations. An individual can be classified as having a slow acetylator (SA), an intermediate acetylator (IA), or a rapid acetylator (RA) phenotype based on its two haplotypes (diplotype) of .