A DNA PROBE TEST FOR DEBRISOQUINE HYDROXYLASE PHENOTYPE

THE LONG-TERM OBJECTIVE IS TO DEVELOP A RELIABLE DNA PROBE TEST FOR THE PREDICTION OF THE DEBRISOQUINE METABOLISM PHENOTYPE. THE SPECIFIC AIMS ARE TO: (1) DEVELOP METHODS FOR PROBING THE CYP2D6 LOCUS ENCODING DEBRISOQUINE HYDROXYLASE INDEPENDENTLY OF THE HIGHLY HOMOLOGOUS BUT UNEXPRESSED CYP2D7 AND CYP2D8P LOCI; (2) DEVELOP A MAMMALIANCELL EXPRESSION SYSTEM FOR GENOMIC COPIES OF THE CYP2D6 LOCUS TO EVALUATE THE EFFECT OF MUTATIONS; (3) DETERMINE IF THE MISSING "C" RESIDUE IN INTRON 5 OF CYP2D6 VARIANT "A" RESULTS IN RETENTION OF INTRON 5 IN MRNA AND, IF SO, DEVELOPA DNA PROBE TEST TO DETECT THE VARIANT "A" SEQUENCE; (4) CLONE AND SEQUENCE THE OTHER MUTANT ALLELES OF CYP2D6 TO DETERMINE THE MUTATIONS RESPONSIBLE FOR LOSS OF ENZYME ACTIVITY; AND (5) DEVELOP A MULTIPLEX DNA PROBE TEST PERMITTING DETECTION OF ALL MUTANT ALLELES IN A SINGLE HYBRIDIZATION. THE FIRST THREE AIMS SHOULD BE COMPLETED IN PHASE I. IN PHASE II, THE CAUSATIVE MUTATIONS FOR THE OTHER MUTANT ALLELES WILL BE DETERMINED, AND DNA PROBE TESTS WILL BE DEVELOPED BY USING THE TOOLS DEVELOPED IN PHASE I. A DNA TEST FOR DEBRISOQUINE METABOLISM WILL PERMIT PREDICTION OF AN INDIVIDUAL'S METABOLISM RATE FOR MORE THAN 20 COMMONLY USED DRUGS. A DNA PROBE TEST FOR SUCH A COMMON GENETIC DEFECT WITH MANY MUTANT ALLELES WILL BE AN EXCELLENT MODEL SYSTEM FOR DEVELOPMENT OF NEW MULTIPLEXING METHODS.