[Nature of diverse molecular diseases in man].

The article comprises the literature data on a new group of enzymopathies in man associated with the defect of the cell reparative mechanisms, which in the norm restore damages of DNA induced by factors of a different character. Special attention is paid to molecular processes observed in the hereditary disease in man--xeroderma characterized by a high sensitivity of the patient to ultraviolet irradiation and by a high incidence of cancer of the skin. Experimental evidences are presented testifying to an elevated sensitivity of cells of such patients to carcinogens, some viruses, and illustrating peculiar features of formation of structural mutations of chromosomes induced by physical, chemical and biological agents. Defects of individual enzymes of reparation in progeria, Fanconi's anemia and some other human diseases are described. The author recommends to simulate defects of reparative enzymes on diploid human cells infected with the virus of leukemia.