POLYMORPHIC N-ACETYLTRANSFERASE (NAT2) GENOTYPING OF EMIRATIS

Polymorphic N-acetyltransferase (NAT2) genotypes were determined in 10 6 unrelated Emiratis by PCR-RFLP analysis to obtain estimates of allel e frequencies. Thirteen different genotypes were found, four associate d with the rapid acetylator phenotype and nine with the slow acetylato r phenotype. Among 67 phenotypically slow acetylators, there was 100% concordance between phenotype and genotype. Among 39 phenotypically ra pid acetylators, 37 possessed at least one wild type allele; a 95% con cordance with genotype. Seven different NAT2 alleles associated with s low acetylation were found. The commonest was a NAT25 type ((CT)-T-48 1) allele which occurred with a frequency of 0.53, a significantly hig her frequency than has been reported for other ethnic groups. A second slow allele, a NAT26 type (G(590)A), occurred with a frequency of 0. 21. The most common genotypes found were NAT25/*5 homozygotes, NAT2*5 /6 heterozygotes and NAT2*4/*5 heterozygotes with frequencies of 0.25 , 0.25 and 0.22 respectively. The high overall prevalence of alleles a ssociated with slow acetylation (173/212; 81.6%) among Emiratis is con sistent with previously reported high frequency of the slow acetylator phenotype in Arabs. Two apparently new slow alleles were identified b ut have not yet been hilly characterized. One appears to be a NAT25 v ariant allele. The other uncharacterized allele appears likely to cont ain an entirely new mutation associated with slow acetylation.