Target conditions[edit]

It has been widely used for the detection of single base mutations, as in genetic diseases.^[2]


LCR and PCR may be used to detect gonorrhea and chlamydia, and may be performed on first-catch urine samples, providing easy collection and a large yield of organisms. Endogenous inhibitors limit the sensitivity, but if this effect could be eliminated, LCR and PCR would have clinical advantages over any other methods of diagnosing gonorrhea and chlamydia.^[3] Among these methods, LCR is emerging as the most sensitive method with high specificity for known single-nucleotide polymorphism (SNP) detection (20). LCR was first developed by Barany, who used thermostable DNA ligase to discriminate between normal and mutant DNA and to amplify the allele-specific product. A mismatch at the 3′ end of the discriminating primer prevents the DNA ligase from joining the two fragments together. By using both strands of genomic DNA as targets for oligonucleotide hybridization, the products generated from two sets of adjacent oligonucleotide primers, complementary to each target strand in one round of ligation, can become the targets for the next round. The amount of the products can thus be increased exponentially by repeated thermal cycling.