The development of molecular biological techniques has allowed to know the root of many genetic diseases , including diseases conditioned deletions and duplications of DNA genomic fragments - CNV ( Copy Number called Variants ) , representing approximately 5.5% of the previously described changes in the genome of pathogenic . One of the methods of examination of deletions and duplications of fragments of the genome is the MLPA ( Multiplex Ligation - called dependent Probe Amplification ) , first described in 2002. It is a technique based on molecular ligation, and PCR , which allows a relative quantitative assessment of different sequences simultaneously 40-45 nucleotide in one reaction . The specific MLPA probes are used which hybridize to complementary segments of DNA examined . These probes are constructed from two fragments which hybridized to the test area, are ligated and then used as a template for one DNA polymerase . After conducting PCR using labeled primers followed by evaluation of the amount of product depends directly on the amount of template , which is evident as a change in fluorescence intensity of the capillary electrophoresis separation with respect to the controls , which are a standard and a reference point for the tested samples . Numerous items of world literature are evidence of the usefulness and high effectiveness of the method in the diagnosis of microdeletion MLPA and mikroduplikacji , aneuploidy and cancer research both in the detection of deletions and duplications critical areas as well as in the study of the methylation status . Its low cost and short time of analysis , low hardware requirements and the ability to test multiple sequences in a single reaction make it a method with great potential and broad application.