DNA repair and related diseases]

DNA-repair is a complex enzymatic process which enables all living cells to withstand the deleterious and mutagenic effects of most genotoxic agents. Defective DNA-repair is caused by mutations involving genes which encode the enzymes responsible for recognition and excision of DNA lesions. Some of these genes have been identified in humans. Several severe human diseases are caused by defective DNA repair affecting the entire genome (e.g. xeroderma pigmentosum and trichotiodystrophy) or only actively transcribed genes (Cockayne's syndrome). Some of these conditions are associated with extremely high rate of cancer.