Molecular genotyping of N-acetylation polymorphism to predict phenotype.

N-acetylation polymorphism is one of the representative pharmacogenetic traits that underlie interindividual and interethnic differences in response to xenobiotics. To develop a practical genotyping method to predict acetylator phenotype, we studied the conditions for accurate phenotyping, and identified the phenotype in 51 Japanese. Then we performed Southern blot analysis of genomic DNA from these subjects using 32P-labeled cDNA for polymorphic N-acetyltransferase in the liver, and found that four N-acetyltransferase alleles generated six genotypes. The present genotyping method predicted the rapid, intermediate, and slow acetylators correctly in 48 of 51 overall subjects (96%) and in all of 4 slow acetylators.