DIVERSE POLYMORPHISM WITHIN A SHORT CODING REGION OF THE HUMAN ALDEHYDE DEHYDROGENASE-5 (ALDH5) GENE

Human aldehyde dehydrogenase-5 gene (originally named as ALDHX) is exp ressed in liver and testis. The ALDH5 does not contain introns in the coding sequence for 517 amino acid residues. Within a short nucleotide region of the gene, the following three nucleotide changes were found in high frequencies, i.e., a silent C<->T at nucleotide (nt) 183, C<- >T at nt 257 associated with a Val<->Ala substitution, and T<->G at nt 320 associated with a Arg<->Leu substitution. The frequency of C at n t 183 is 81% in Caucasians and 65% in Japanese, and the difference is statistically not significant. The frequency of C at nt 257 is 76% in Caucasians and 55% in Japanese, and the difference is statistically si gnificant (P = 0.02). The frequency of T at nt 320 is 71% in Caucasian s, while it is only 27% in Japanese. The racial difference at nt 320 i s highly significant (P < 0.001). No significant difference was found in the genotypes of the three nucleotide positions between alcoholic a nd nonalcoholic Caucasians within the limited numbers of subjects exam ined.