Identification of single-nucleotide polymorphisms (SNPs) of human N-acetyltransferase genes NAT1, NAT2, AANAT, ARD1 and L1CAM in the Japanese population.

By direct sequencing of regions of the human genome containing five genes belonging to the acetyltransferase family, arylamine N-acetyltransferase (NAT1), arylamine N-acetyltransferase (NAT2), arylalkylamine N-acetyltransferase (AANAT), L1 cell adhesion molecule (L1CAM), and the human homolog of Saccharomyces cerevisiae N-acetyltransferase ARD1, we identified 53 single-nucleotide polymorphisms (SNPs) and two insertion/ deletion polymorphisms in 48 healthy Japanese volunteers. NAT1 and NAT2 are so-called drug-metabolizing enzymes. In the NAT1 gene we found two SNPs and a 3-bp insertion/ deletion polymorphism that corresponded to the NAT1*3, *10, and *18A/*18B alleles reported in other populations. The frequencies of NAT1* alleles in our Japanese subjects were 52.6% for NAT1*4, 1.0% for NAT1*3, 40.6% for NAT1*10, 2.6% for NAT1*18A and 3.1% for NAT1*18B. In the NAT2 gene we found 32 SNPs and a 1-bp insertion/ deletion polymorphism; 6 SNPs within the coding region were reported previously and belonged to the slow acetylator group (NAT2*5, NAT2*6 and NAT2*7), and 2 of the 8 SNPs in the 5' flanking region were reported in the dbSNP of GenBank, but the remaining 24 SNPs and the insertion/deletion polymorphism were novel. The frequencies of NAT2* alleles in Japanese (51.3% for NAT2*4, 1.6% for *5B, 26.1% for *6A, 2.2% for *6B, 1.2% for *7A, 10.1% for *7B, 7.4% for *12A, and 1.1% for *13) were significantly different from those reported in Caucasian populations. In the AANAT gene we found 4 novel SNPs: 2 in the 5' flanking region, 1 in exon 4, and 1 in intron 3. In the two genes belonging to the N-terminal N-acetyltransferase family, we identified 9 SNPs, 7 of them novel, for ARD1, and six novel SNPs for L1CAM. Variations at these loci may contribute to an understanding of the way in which different genotypes may affect the activities of human N-acetyltransferases, especially as regards the therapeutic efficacy of certain drugs and antibiotics.