title: Graves' disease in monozygotic twins - a case report.
abstract: BACKGROUND
  Autoimmune thyroid diseases including Graves' disease and Hashimoto's thyroiditis are caused by immune response to self-thyroid antigens. The rare situation of hyperthyroidism with Graves' disease in twins has been reported in a very few case reports in literature.
  
  
  METHODS
  We present monozygotic female twins developing consecutively Graves' disease within five years. One year before the diagnosis of Graves' disease was established in the first twin, the mother developed a toxic thyroid nodule with hyperthyroidism leading to hemi thyroidectomy. Both the mother and the twins were cigarette smokers. The twins were treated with carbamizole and this therapy led to normalization of thyroid stimulating hormone and thyroxine.
  
  
  CONCLUSIONS
  This case report supports the hypothesis that a genetic factor as well as an environmental factor (cigarette smoking) might be of great importance in the aetiology of Graves' disease.
authors.affiliation: Institute of General Practice and Health Services Research, University of Zurich, Zurich, Switzerland. beat.knechtle@hispeed.ch.
authors.forename: Christoph A
authors.initials: CA
authors.lastname: Rüst
authors.forename: Beat
authors.initials: B
authors.lastname: Knechtle
authors.forename: Thomas
authors.initials: T
authors.lastname: Rosemann