Detection of Novel ALAD Gene Polymorphisms Using Denaturing High-Performance Liquid Chromatography

Denaturing high-performance liquid chromatography (DH-PLC), which is based on the separation of mismatched DNA heteroduplexes, is one of the most promising techniques for detecting nucleotide polymorphisms. Lead is an important environmental toxicant that can impair the cardiovascular, central nervous, renal, reproductive, and hematologic systems. Here we compare the sensitivity and efficiency of DNA polymorphism detection in the delta-aminolevulinate dehydratase (ALAD) gene encoding the principal lead-binding protein in humans by means of DHPLC and direct DNA sequencing of polymerase chain reaction amplicons. In a sample of 48 unrelated Chinese women, five novel mutations were discovered in intron 6 (G13298C). exon 7 (C13348T), intron 8 (C13847T), intron 12 (C15096T), and the 3' untranslated region of exon 13 (A15762C). The allele frequencies of C13298, T13348, T13847, T15096, and C15762 alleles were 21.3%, 2.3%. 82.1%, 62.5%, and 1.1%, respectively. All five mutations were detected by both DHPLC and direct DNA sequencing. No previously reported missense ALAD mutations were found in this Chinese population. Our study confirms that DHPLC provides an accurate method for the rapid identification of single nucleotide polymorphisms.