DETECTION OF A POINT MUTATION USING SHORT OLIGONUCLEOTIDE PROBES IN ALLELE-SPECIFIC HYBRIDIZATION

Two nonradioactive and simple procedures were developed to detect the A985G point mutation that causes medium-chain acyl-CoA deficiency. In both of these assays, short oligonucleotide probes were used in allele -specific hybridization combined with DNA amplification. The lower lim it for a useful probe was found to be between 9 and 12 base pairs. Tim e-resolved fluorometry was utilized as the label technology and microt itration plates as the solid support. In one of the assay formats, pro bes labeled with europium and samarium chelates were used to simultane ously detect the mutant and normal alleles from the same hybridization reaction. In addition, the discrimination efficiency of different pro bes was characterized by cross-reactivity determinations and by measur ing affinities of the probes towards fully, complementary as well as c owards mismatch-forming target oligonucleotides. All of the 80 coded p atient samples analyzed were correctly typed in both of the assay form ats used.