In order to identify the mutations of genes responsible for genetic diseases, our Laboratory uses an analysis of DNA fragments created after treating of the tested genes with restriction enzymes - RFLP (Restriction Fragment Length Polymorphism). Even a change of a single nucleotide in the sequence recognized by the enzyme causes that it will not cut DNA. This means that e.g. in two different persons whose DNA is analysed, a different number of DNA fragments will be created which are the products of decomposition of the primary DNA particle (reproduced in the PCR reaction). These fragments will also differ in their size. The electrophorese conducted after treatment enables differentiation of these fragments. Based on the analysis of the image after electrophorese, the conclusions can be made about the presence of mutations causing occurrence of a given genetic disease.