[Hereditary diseases with primary and secondary DNA repair defects]

Two basic ways of DNA repair are discussed. The first one is nucleotide excision repair after exposure to UV light regarded on using examples of various eukaryotic cells, detailed description of human diseases related to genetic defects of this process (xeroderma pigmentosum, Cockayne's syndrome, and trychotiodystrophy). Contemporary ideas on genetics of excision repair are presented. Relevant genes and their mutations are shown. The second one is a process of double strand breaks repair regarded as the basic type of lethal damage, provoked by ionizing radiation. This process was first described for eukaryotes, and then it was considered in relation to some diseases, such as ataxia-telangiectasia (Louis-Bar's syndrome), Nijmegen chromosome breakage syndrome, Bloom's syndrome, Fancomi's anemia, and progerias, for which hypersensitivity to gamma-rays and different chemicals are typical. Contemporary views concerning the involvement of repair processes in the aforementioned diseases are presented and discussed.