[Genetic and environmental factors in Graves disease. A review]

The aetiology of Graves' disease fits a multifactorial pattern of inheritance, where an interplay of genetic and environmental factors is necessary for the development of autoimmune hyperthyroidism. Family studies, twin studies and studies of genetic markers all confirm the existence of one or more genetic factors in the aetiology of Graves' disease. Since the familial occurrence of Graves' disease cannot be fully explained by the distribution of genetic markers, there may also exist one or more environmental factors in the aetiology of Graves' disease. Environmental factors such as iodine intake, exposure to certain drugs, smoking habits, stressful life events and a number of infectious agents have all been found associated with Graves' disease. There is no evidence of an environmental factor as a causative factor in Graves' disease. Future studies should be carried out prospectively involving both patients with Graves' disease and genetically predisposed persons, e.g. the families of patients with Graves' disease. Prospective population-based studies among monozygotic twins discordant for Graves' disease offer unique opportunities to clarify the role of environmental factors in the aetiology of Graves' disease.