Simultaneous occurrence of type 1 diabetes mellitus and Graves' disease: a report of two cases and a review of the literature.

Two unrelated Japanese women, 41 and 27 years of age, were admitted with histories of thirst, weight loss and palpitations of a few weeks' duration. Both were diagnosed to have diabetic ketosis or ketoacidosis with acute-onset type 1 diabetes (T1D) and Graves' disease (GD) (autoimmune polyglandular syndrome type 3 variant; APS3v), and were treated with intensive insulin therapy and anti-thyroid drugs. Human leukocyte antigen examinations showed that both cases had the HLA-A2, A24, B54, and DRB1*04:05-DQA1*03:03-DQB1*04:01 haplotype, which made them susceptible not only to APS3v, but also to both acute-onset T1D and GD. The genetic background of patients strongly contributes to the simultaneous occurrence of T1D and GD.