A new approach for the rapid detection of common and atypical aldehyde dehydrogenase alleles

A strong protection against the development of alcoholism is exerted by a point mutation in the gene coding for low Km aldehyde dehydrogenase (ALDH), i.e. ALDH2. We report a non-radioactive method for determining the common and atypical human mitochondrial aldehyde dehydrogenase (ALDH2) genotypes. This method is based on the fact that the base change (G-->A) in Exon 12 of the ALDH2 gene abolishes an Eco57 I restriction site (CTGAAG-->CTAAAG). A GC-clamp attached oligonucleotide was designed to yield a 176 base pair product by the polymerase chain reaction. After amplification, the resulting fragment containing the normal nucleotide sequence is cut by Eco57 I into two segments (131 base pairs + 45 base pairs) while the fragment containing the mutated sequence remains intact (176 base pairs). These are visualized by staining with ethidium bromide on agarose gels without blotting, hybridization or autoradiography.