Study on Genotyping Polymorphism and Sequencing of N‐Acetyltransferase 2 (NAT2) among Al‐Ahsa Population

Abstract

One of the well-studied phase II drug metabolizing enzymes is N-acetyltransferase 2 (<i>NAT2</i>) which has an essential role in the detoxification and metabolism of several environmental toxicants and many therapeutic drugs like isoniazid (antituberculosis, TB) and antimicrobial sulfonamides. According to the variability in the acetylation rate among different ethnic groups, individuals could be classified into slow, intermediate, and fast acetylators; these variabilities in the acetylation rate are a result of single nucleotide polymorphisms (SNPs) in the coding sequence of <i>NAT2</i>. The variety of <i>NAT2</i> acetylation status is associated with some diseases such as bladder cancer, colorectal cancer, rheumatoid arthritis, and diabetes mellitus. The main objectives of this research are to describe the genetic profile of <i>NAT2</i> gene among the people of the Al-Ahsa region, to detect the significant SNPs of this gene, to determine the frequency of major <i>NAT2</i> alleles and genotypes, and then categorize them into fast, intermediate, and slow acetylators. Blood samples were randomly collected from 96 unrelated people from Al-Ahsa population, followed by DNA extraction then amplifying the <i>NAT2</i> gene by polymerase chain reaction (PCR); finally, functional <i>NAT2</i> gene (exon 2) was sequenced using the Sanger sequencing method. The well-known seven genetic variants of <i>NAT2</i> gene are 191G>A, 282C>T, 341T>C, 481C>T, 590G>A, 803A>G, and 857G>A were detected with allele frequencies 1%, 35.4%, 42.7%, 41.1%, 29.2%, 51%, and 5.7%, respectively. The most common <i>NAT2</i> genetic variant among Al-Ahsa population was 803A>G with a high frequency 0.510 (95% confidence interval 0.44-0.581) followed by 341T>C 0.427 (95% confidence interval 0.357-0.497). The most frequent two haplotypes of <i>NAT2</i> were <i>NAT2</i>∗<i>6C</i> (25.00%) and <i>NAT2</i>∗<i>5A</i> (22.92%) which were classified as a slow acetylators. According to trimodal distribution of acetylation activity, the predicted phenotype of Al-Ahsa population was found to be 5.21% rapid acetylators, 34.38% intermediate acetylators, and 60.42% were slow acetylators. In addition, this study found four novel haplotypes <i>NAT2</i>∗<i>5</i>TB, <i>NAT2</i>∗<i>5AB</i>, <i>NAT2</i>∗<i>5ZA</i>, and <i>NAT2</i>∗<i>6</i>W which were slow acetylators. This study revealed a high frequency of the <i>NAT2</i> gene with slow acetylators (60.42%) in Al-Ahsa population, which might alter the drug's efficacy and vulnerability to some diseases.