THE FREQUENCY OF THE MITOCHONDRIAL ALDEHYDE DEHYDROGENASE I-2 (ATYPICAL) ALLELE IN CAUCASIAN, ORIENTAL AND AFRICAN BLACK POPULATIONS DETERMINED BY THE RESTRICTION PROFILE OF PCR-AMPLIFIED DNA

The aldehyde dehydrogenase I (ALDH I) gene codes for a mitochondrial e nzyme which plays a major role in hepatic alcohol detoxication. It has been related to alcohol flushing in Orientals bearing the atypical AL DH I-2 gene. The variant protein results from a lysine for glutamate s ubstitution at position 487 (G --> A change in exon 12). A procedure f or ALDH I-2 detection consisting in a differentiation between the 'aty pical' allele and the 'wild' allele has been improved through PCR and subsequent MboII digestion. Blood samples collected on anticoagulant o r directly absorbed on blotting paper were used for DNA amplification in the presence of two specific oligonucleotidic primers, each one abl e to incorporate a restriction site in the amplimer. After MboII diges tion, PCR products were separated by polyacrylamide gel electrophoresi s and then visualized with ethidium bromide. This technique permits a rapid and non-radioactive detection of atypical ALDH I-2 on a PCR prod uct without the use of allele specific oligonucleotides. It was applie d to the study of ALDH I-2 allele frequency in random population sampl es of three ethnic groups: Caucasians, Orientals and African blacks.