NAT2 Genotyping Analysis and Inferred Phenotype.

Buccal cell DNA was isolated using QIAGEN DNeasy Blood & Tissue Kit (Hilden, Germany) according to manufacturer’s instructions. Single nucleotide polymorphisms (SNP) in the NAT2 coding region and their corresponding haplotypes were determined using four-SNP assays, i.e., rs181280, c.341T>C; rs1799930, c.590G>A; rs1799931, c.857G>A; rs1801279, c.191G>A, with TaqMan Assays from Thermo Fisher Scientific (Waltham, MA). Subjects were classified as slow acetylators (SA) if they had 2 reduced-activity NAT2 alleles (*5, *6, *7, or *14), or rapid acetylators (RA) if they carried 1 reduced-activity allele and 1 fully functional allele (*4), or 2 fully functional alleles⁴².