Genotype and allele frequencies of <i>TPMT</i>, <i>NAT2</i>, <i>GST</i>, <i>SULT1A1</i> and <i>MDR‐1</i> in the Egyptian population

<jats:p><jats:bold>Aims </jats:bold> The goal of this study was to determine the frequencies of important allelic variants in the <jats:italic>TPMT</jats:italic>, <jats:italic>NAT2</jats:italic>, <jats:italic>GST, SULT1A1</jats:italic> and <jats:italic>MDR‐1</jats:italic> genes in the Egyptian population and compare them with the frequencies in other ethnic populations.</jats:p><jats:p><jats:bold>Methods </jats:bold> Genotyping was carried out in a total of 200 unrelated Egyptian subjects. <jats:italic>TPMT</jats:italic>*<jats:italic>2</jats:italic> was detected using an allele‐specific polymerase chain reaction (PCR) assay. <jats:italic>TPMT</jats:italic>*<jats:italic>3C</jats:italic> and <jats:italic>NAT2</jats:italic> variants (*<jats:italic>5,</jats:italic>*<jats:italic>6</jats:italic> and *<jats:italic>7</jats:italic>) were detected using an allele‐specific real‐time PCR assay. Detection of <jats:italic>GSTM1</jats:italic> and <jats:italic>GSTT1</jats:italic> null alleles was performed simultaneously using a multiplex PCR assay. Finally, a PCR‐restriction fragment length polymorphism assay was applied for the determination of <jats:italic>TPMT</jats:italic>*<jats:italic>3A</jats:italic> (*<jats:italic>3B</jats:italic>)<jats:italic>, SULT1A1</jats:italic>*<jats:italic>2</jats:italic> and <jats:italic>MDR‐1</jats:italic> (<jats:italic>3435T</jats:italic>) variants.</jats:p><jats:p><jats:bold>Results </jats:bold> Genotyping of <jats:italic>TPMT</jats:italic> revealed frequencies of 0.003 and 0.013 for <jats:italic>TPMT</jats:italic>*<jats:italic>3A</jats:italic> and <jats:italic>TPMT</jats:italic>*<jats:italic>3C</jats:italic>, respectively. No <jats:italic>TPMT</jats:italic>*<jats:italic>2</jats:italic> or *<jats:italic>3B</jats:italic> was detected in the analysed samples. The frequencies of specific <jats:italic>NAT2</jats:italic> alleles were 0.215, 0.497, 0.260 and 0.028 for *<jats:italic>4</jats:italic> (wild‐type), *<jats:italic>5</jats:italic> (341C), *<jats:italic>6</jats:italic> (590A) and *<jats:italic>7</jats:italic> (857A), respectively. <jats:italic>GSTM1</jats:italic> and <jats:italic>GSTT1</jats:italic> null alleles were detected in 55.5% and 29.5% of the subjects, respectively. <jats:italic>SULT1A1</jats:italic>*<jats:italic>2</jats:italic> was detected at a frequency of 0.135. Finally, the frequencies of the wild‐type allele (<jats:italic>3435C</jats:italic>) and the <jats:italic>3435T</jats:italic> variant in the <jats:italic>MDR‐1</jats:italic> gene were found to be 0.6 and 0.4, respectively.</jats:p><jats:p><jats:bold>Conclusions </jats:bold> We found that Egyptians resemble other Caucasians with regard to allelic frequencies of the tested variants of <jats:italic>NAT2</jats:italic>, <jats:italic>GST</jats:italic> and <jats:italic>MDR‐1</jats:italic>. By contrast, this Egyptian population more closely resemble Africans with respect to the <jats:italic>TPMT</jats:italic>*<jats:italic>3C</jats:italic> allele, and shows a distinctly different frequency with regard to the <jats:italic>SULT1A1</jats:italic>*<jats:italic>2</jats:italic> variant. The predominance of the slow acetylator genotype in the present study (60.50%) could not confirm a previously reported higher frequency of the slow acetylator phenotype in Egyptians (92.00%), indicating the possibility of the presence of other mutations not detectable as T341C, G590A and G857A. The purpose of our future studies is to investigate for new polymorphisms, which could be relatively unique to the Egyptian population.</jats:p>